Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?
2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?
3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?

I would really appreciate your feedback.
Thank you,

On 9 Apr, 04:54, "okbran" wrote:

Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery?

current draw depends almost entirely on the load

How come they don't label the
current output on these car batteries?
2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?

then 13A flows thru the cables, presumably. Nothing else happens,
cables have a fair amount of margin in their ratings. If you ran 130A
through it it'd melt.

3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?
I would really appreciate your feedback.
Thank you,


NT

In article om,
okbran wrote:
Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?

There is no 'average' output current - the current depends on the load
which will vary according to what electrics are in use. But of course with
the engine running the alternator supplies all the current needed for
pretty well all the time.

However, the other figure given with batteries is the capacity in
amp/hours. Since this is measured over a constant time regardless of
actual capacity means the current drawn during measurement will vary.

2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?

Same as with any other power source - if the cable is too small it will
allow too much voltage drop at best and at worse burn out.

3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?

Yes. See above. You need to use cable rated at the maximum current you're
going to draw.

--
*Is there another word for synonym?

Dave Plowman London SW
To e-mail, change noise into sound.

"okbran" wrote in message
ps.com...
Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?
2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?
3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?

I would really appreciate your feedback.
Thank you,


Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H battery
will take 14 hours to charge at one amp. Starter motor current is ~50amp.
Obviously they can put out much greater current than their A/H rating.
They're rated this way mostly to keep them from being over charged. A car
battery is used for starting only so cranking current is all that's really
needed. Theirs no good reason to short either type battery. A 10A rated
cable means it's rated to carry 10A, not that 10A will flow when shorting
across a battery.

If you want to now what happens, hold the ends of paper clip on to a fresh
D-cell battery with your fingers.;0)

Captain Midnight wrote:

"okbran" wrote in message
ps.com...
Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?
2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?
3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?

I would really appreciate your feedback.
Thank you,


Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H battery
will take 14 hours to charge at one amp.


No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the stored
energy is lost as heat.


Starter motor current is ~50amp.


For a motorcycle? Some cars don't use that much current to turn the
engine over.


Obviously they can put out much greater current than their A/H rating.


Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to explode,
or to melt the internal lead connections between the individual cells.


They're rated this way mostly to keep them from being over charged. A car
battery is used for starting only so cranking current is all that's really
needed. Theirs no good reason to short either type battery. A 10A rated
cable means it's rated to carry 10A, not that 10A will flow when shorting
across a battery.

If you want to now what happens, hold the ends of paper clip on to a fresh
D-cell battery with your fingers.;0)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

okbran wrote:

Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?
2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?


Rated at 10 amps for what application? it depends on if its wound on
a transformer, in a bundle or conduit, the type of insulation,
acceptable voltage drop and duty cycle, along with the temperature.


3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?


Worst case is when the insulation has a flash fire and hot copper is
spattered everywhere. For that kind of current I would use #1 welding
cable. The whole idea of jumper cables is to start the engine quickly.
The battery is discharged, and you still need the full current the
starter demands. That means that you need as low of a resistance
connection between the two batteries. It also helps to let the dead
battery be charged for a couple minutes before you try to start the
engine. That allows the dead battery's terminal voltage to rise a bit,
and reduce its demand while cranking.


I would really appreciate your feedback.
Thank you,


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

On 9 Apr, 12:25, "Michael A. Terrell"
wrote:
Captain Midnight wrote:

Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H battery
will take 14 hours to charge at one amp.

No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage.

Ah rating is only correct for a 20hr discharge. Faster discharge will
give lower than proportional capacity.

It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy.

Charge time depends entirely on charge rate.


Starter motor current is ~50amp.

For a motorcycle? Some cars don't use that much current to turn the
engine over.

Fiat 500? Trabant?


NT

1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?

They are rated with current output. Current is described in Amps. CCA is
cold-cranking Amps. There is no "average" current. If you want to light a
small 12v bulb with a battery, you'll get a few tenths of an amp output. If
you want to crank an engine's starting motor, you'll get a few tens or
hundred of amps, depending on the motor. The battery will supply a trickle or
a flood of current depending on what you connect to it. That's true of all
batteries and why you have to be careful what you connect to one.

2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?

If the cable is too small for the current you need to supply, it will
probably get warm (or hot!) and the voltage will drop below 12 volts. It's
always best to use a cable that's bigger than required for the job.

3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?

See answer #2.

Thank you,

You're welcome.
--
DaveC

This is an invalid return address
Please reply in the news group

Starter motor current is ~50amp.



For a motorcycle? Some cars don't use that much current to turn the
engine over.



Well my car with a relatively small 2.3L 4 cylinder engine has a starter
motor rated at 1.4KW, so well over 100A. I'm not sure if this is typical
but the starter is powerful enough to move the car if I put it in gear
and turn the key. I suspect larger engines typically have even more
powerful starters.

"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:

"okbran" wrote in message
ps.com...
Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?
2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?
3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?

I would really appreciate your feedback.
Thank you,


Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H
battery
will take 14 hours to charge at one amp.


No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the stored
energy is lost as heat.


Starter motor current is ~50amp.


For a motorcycle? Some cars don't use that much current to turn the
engine over.


Obviously they can put out much greater current than their A/H rating.


Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to explode,
or to melt the internal lead connections between the individual cells.


No. A typical car battery is 50A/H. Even a small car battery will be rated
300CCA. It's not the same rating. Problems can happen to the battery from
it's over use but the biggest reason to not use it for long is to keep from
burning up the starter.

In article tqvSh.13654$Rg2.5267@trndny02,
James Sweet wrote:
Well my car with a relatively small 2.3L 4 cylinder engine has a starter
motor rated at 1.4KW, so well over 100A. I'm not sure if this is typical
but the starter is powerful enough to move the car if I put it in gear
and turn the key. I suspect larger engines typically have even more
powerful starters.

The current needed depends on several things - notably how much friction
in the engine which varies between cold and hot.

--
*Plagiarism saves time *

Dave Plowman London SW
To e-mail, change noise into sound.

Captain Midnight wrote:

"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:

Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H
battery
will take 14 hours to charge at one amp.


No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the stored
energy is lost as heat.


Starter motor current is ~50amp.


For a motorcycle? Some cars don't use that much current to turn the
engine over.


Obviously they can put out much greater current than their A/H rating.


Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to explode,
or to melt the internal lead connections between the individual cells.


No. A typical car battery is 50A/H. Even a small car battery will be rated
300CCA. It's not the same rating. Problems can happen to the battery from
it's over use but the biggest reason to not use it for long is to keep from
burning up the starter.


I state that the CA/CCA is higher than the A/H rating, and you say
that's not true. Interesting.

BTW, have you ever seen the damage done to a vehicle when a car
battery explodes and sprays acid all over the engine compartment? I've
seen several, here in Central Florida. One exploded while parked in the
hot sun, and hadn't been used in over 8 hours.


A starter will be damaged faster by low voltage, or excessive voltage
drop in the solenoid and all of the cables. I had to install #1 welding
cable on the customized 389 8 cylinder engine in my '66 GTO that had
over 220 pounds compression. When the engine was warm, it drew over 400
amps from the battery, but only for a second or so. If it didn't start
you waited ten seconds to let everything cool. That rarely ever
happened.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Dave Plowman (News)" wrote:

In article tqvSh.13654$Rg2.5267@trndny02,
James Sweet wrote:
Well my car with a relatively small 2.3L 4 cylinder engine has a starter
motor rated at 1.4KW, so well over 100A. I'm not sure if this is typical
but the starter is powerful enough to move the car if I put it in gear
and turn the key. I suspect larger engines typically have even more
powerful starters.

The current needed depends on several things - notably how much friction
in the engine which varies between cold and hot.


I have never looked at the specs on the electrical system on a bike.
Years ago any car starter that drew over 70 amps, no load was considered
defective. That's why I asked.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Michael A. Terrell wrote:
BTW, have you ever seen the damage done to a vehicle when a car
battery explodes and sprays acid all over the engine compartment? I've
seen several, here in Central Florida. One exploded while parked in the
hot sun, and hadn't been used in over 8 hours.

My car obviously had a battery explosion, or at least a severe boil-over
at some point in its life. The paint is gone off the front bumper cover
in a spatter pattern in front of the battery area, and the battery tray
itself is nearly rusted out in spite of the rest of the car being rust-free.

Had one explode on a travel trailer once, too. The battery was in a
plastic battery box on the front A-frame and had been on trickle charge
for about three months. This was in the middle of winter. It threw
shrapnel a foot or two on either side.

Michael A. Terrell wrote:
Captain Midnight wrote:
"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:
Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H
battery
will take 14 hours to charge at one amp.

No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the stored
energy is lost as heat.


Starter motor current is ~50amp.

For a motorcycle? Some cars don't use that much current to turn the
engine over.


Obviously they can put out much greater current than their A/H rating.

Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to explode,
or to melt the internal lead connections between the individual cells.

No. A typical car battery is 50A/H. Even a small car battery will be rated
300CCA. It's not the same rating. Problems can happen to the battery from
it's over use but the biggest reason to not use it for long is to keep from
burning up the starter.


I state that the CA/CCA is higher than the A/H rating, and you say
that's not true. Interesting.

BTW, have you ever seen the damage done to a vehicle when a car
battery explodes and sprays acid all over the engine compartment? I've
seen several, here in Central Florida. One exploded while parked in the
hot sun, and hadn't been used in over 8 hours.


A starter will be damaged faster by low voltage, or excessive voltage
drop in the solenoid and all of the cables. I had to install #1 welding
cable on the customized 389 8 cylinder engine in my '66 GTO that had
over 220 pounds compression. When the engine was warm, it drew over 400
amps from the battery, but only for a second or so. If it didn't start
you waited ten seconds to let everything cool. That rarely ever
happened.

Hi...

I respectfully submit that CA/CCA have absolutely nothing in common with
A/H. Apples and oranges.

Take care.

Ken

"David Brodbeck" wrote in message
t...

Had one explode on a travel trailer once, too. The battery was in a
plastic battery box on the front A-frame and had been on trickle charge
for about three months. This was in the middle of winter. It threw
shrapnel a foot or two on either side.

Froze up?

Ken Weitzel wrote:

Michael A. Terrell wrote:
Captain Midnight wrote:
"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:
Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H
battery
will take 14 hours to charge at one amp.

No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the stored
energy is lost as heat.


Starter motor current is ~50amp.

For a motorcycle? Some cars don't use that much current to turn the
engine over.


Obviously they can put out much greater current than their A/H rating.

Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to explode,
or to melt the internal lead connections between the individual cells.

No. A typical car battery is 50A/H. Even a small car battery will be rated
300CCA. It's not the same rating. Problems can happen to the battery from
it's over use but the biggest reason to not use it for long is to keep from
burning up the starter.


I state that the CA/CCA is higher than the A/H rating, and you say
that's not true. Interesting.

BTW, have you ever seen the damage done to a vehicle when a car
battery explodes and sprays acid all over the engine compartment? I've
seen several, here in Central Florida. One exploded while parked in the
hot sun, and hadn't been used in over 8 hours.


A starter will be damaged faster by low voltage, or excessive voltage
drop in the solenoid and all of the cables. I had to install #1 welding
cable on the customized 389 8 cylinder engine in my '66 GTO that had
over 220 pounds compression. When the engine was warm, it drew over 400
amps from the battery, but only for a second or so. If it didn't start
you waited ten seconds to let everything cool. That rarely ever
happened.

Hi...

I respectfully submit that CA/CCA have absolutely nothing in common with
A/H. Apples and oranges.

Take care.

Ken


Please show me where I said that it did. I simply agreed that the
CA/CCA was a higher current than the battery was normally used at.


The A/H rating is simply a way to state the amount of stored
electrical energy that you can expect at a specified discharge current
and temperature for that battery, when it is in good condition.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Homer J Simpson wrote:
"David Brodbeck" wrote in message
t...

Had one explode on a travel trailer once, too. The battery was in a
plastic battery box on the front A-frame and had been on trickle charge
for about three months. This was in the middle of winter. It threw
shrapnel a foot or two on either side.

Froze up?

Probably. To say that the battery chargers in RV power converters are
often poorly designed would be, perhaps, too kind.

David Brodbeck wrote:

Michael A. Terrell wrote:
BTW, have you ever seen the damage done to a vehicle when a car
battery explodes and sprays acid all over the engine compartment? I've
seen several, here in Central Florida. One exploded while parked in the
hot sun, and hadn't been used in over 8 hours.

My car obviously had a battery explosion, or at least a severe boil-over
at some point in its life. The paint is gone off the front bumper cover
in a spatter pattern in front of the battery area, and the battery tray
itself is nearly rusted out in spite of the rest of the car being rust-free.


My last car had pinholes in that corner of the hood The battery
exploded when my Dad owned it. The '79 Dodge 1/2 Ton Limited Edition
pickup truck I want to restore has damage. The previous owner was a
hack mechanic and caused the battery to explode. The only real fix I've
found is to braze the holes shut, then grind down both surfaces, if
possible. In enclosed area there is rusty slag on the surface, but it
doesn't cause any problems, and can't be seen. The ford ranger I'm
driving now has damage, but i don't know what happened to it.


Had one explode on a travel trailer once, too. The battery was in a
plastic battery box on the front A-frame and had been on trickle charge
for about three months. This was in the middle of winter. It threw
shrapnel a foot or two on either side.



--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Michael A. Terrell wrote:
My last car had pinholes in that corner of the hood The battery
exploded when my Dad owned it.


Oddly, the hood on mine is OK. This suggests one of two things:

- The battery explosion was the result of a collision, and the hood was
replaced. I don't think it's that, because the cowl area near the
battery is rusty, and any collision damage would have affected it, too.

- The battery explosion happened with the hood up. Jump-starting
accident, maybe?


Another thing that puzzles me is the current battery has a tendency to
weep liquid out of the cell covers. Normally I'd assume this was
boilover due to overcharging, but the charging voltage is normal.

"James Sweet" wrote in message
news:tqvSh.13654$Rg2.5267@trndny02...


Starter motor current is ~50amp.



For a motorcycle? Some cars don't use that much current to turn the
engine over.



Well my car with a relatively small 2.3L 4 cylinder engine has a starter
motor rated at 1.4KW, so well over 100A. I'm not sure if this is typical
but the starter is powerful enough to move the car if I put it in gear
and turn the key. I suspect larger engines typically have even more
powerful starters.

That's for an average MC starter.

"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:

"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:

Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H
battery
will take 14 hours to charge at one amp.


No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the
stored
energy is lost as heat.


Starter motor current is ~50amp.


For a motorcycle? Some cars don't use that much current to turn
the
engine over.


Obviously they can put out much greater current than their A/H
rating.


Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to
explode,
or to melt the internal lead connections between the individual cells.


No. A typical car battery is 50A/H. Even a small car battery will be
rated
300CCA. It's not the same rating. Problems can happen to the battery
from
it's over use but the biggest reason to not use it for long is to keep
from
burning up the starter.


I state that the CA/CCA is higher than the A/H rating, and you say
that's not true. Interesting.

BTW, have you ever seen the damage done to a vehicle when a car
battery explodes and sprays acid all over the engine compartment? I've
seen several, here in Central Florida. One exploded while parked in the
hot sun, and hadn't been used in over 8 hours.


A starter will be damaged faster by low voltage, or excessive voltage
drop in the solenoid and all of the cables. I had to install #1 welding
cable on the customized 389 8 cylinder engine in my '66 GTO that had
over 220 pounds compression. When the engine was warm, it drew over 400
amps from the battery, but only for a second or so. If it didn't start
you waited ten seconds to let everything cool. That rarely ever
happened.


Obviously they can put out much greater current than their A/H
rating.

Yes, that is the CA/CCA rating, and it is for very short bursts
during starting.

I miss read this as you meant A/H and CA/CCA being the same thing. Sorry. It
was getting early.
I have always charged to the A/H and it comes out consistent with DMM and
hydrometer before that. Really not significant when posting to someone
wanting to short out batteries though.

Have never seen a battery explode or one that had exploded. I'm sure I came
very close, many decades ago, when jumping a 6 volt car with a 12 volt car.
Have only seen a few starters burnt up from over cranking either. Most
people know not to do it.

Voltage and current are not mutually exclusive If current draw is high
enough then it drops the voltage. Either from resistance or lack of battery
capacity. If ignition voltage is dropped enough the plugs don't fire.
However it happens it's the heat that kills. That certainly wouldn't be any
kind of an engine a person could use for a year round driver around here.

On 9 Apr, 20:16, "Michael A. Terrell"
wrote:
"Dave Plowman (News)" wrote:
In article tqvSh.13654$Rg2.5267@trndny02,
James Sweet wrote:

Well my car with a relatively small 2.3L 4 cylinder engine has a starter
motor rated at 1.4KW, so well over 100A. I'm not sure if this is typical
but the starter is powerful enough to move the car if I put it in gear
and turn the key. I suspect larger engines typically have even more
powerful starters.

The current needed depends on several things - notably how much friction
in the engine which varies between cold and hot.

I have never looked at the specs on the electrical system on a bike.
Years ago any car starter that drew over 70 amps, no load was considered
defective. That's why I asked.

on load current will be far higher though.


NT

Captain Midnight wrote:

"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:

"Michael A. Terrell" wrote in message
...
Captain Midnight wrote:

Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H
battery
will take 14 hours to charge at one amp.


No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the
stored
energy is lost as heat.


Starter motor current is ~50amp.


For a motorcycle? Some cars don't use that much current to turn
the
engine over.


Obviously they can put out much greater current than their A/H
rating.


Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to
explode,
or to melt the internal lead connections between the individual cells.


No. A typical car battery is 50A/H. Even a small car battery will be
rated
300CCA. It's not the same rating. Problems can happen to the battery
from
it's over use but the biggest reason to not use it for long is to keep
from
burning up the starter.


I state that the CA/CCA is higher than the A/H rating, and you say
that's not true. Interesting.

BTW, have you ever seen the damage done to a vehicle when a car
battery explodes and sprays acid all over the engine compartment? I've
seen several, here in Central Florida. One exploded while parked in the
hot sun, and hadn't been used in over 8 hours.


A starter will be damaged faster by low voltage, or excessive voltage
drop in the solenoid and all of the cables. I had to install #1 welding
cable on the customized 389 8 cylinder engine in my '66 GTO that had
over 220 pounds compression. When the engine was warm, it drew over 400
amps from the battery, but only for a second or so. If it didn't start
you waited ten seconds to let everything cool. That rarely ever
happened.


Obviously they can put out much greater current than their A/H
rating.

Yes, that is the CA/CCA rating, and it is for very short bursts
during starting.

I miss read this as you meant A/H and CA/CCA being the same thing. Sorry. It
was getting early.


Not a problem. It just didn't read the same to me


I have always charged to the A/H and it comes out consistent with DMM and
hydrometer before that. Really not significant when posting to someone
wanting to short out batteries though.


There is not a big difference between the charge and discharge
currents, but it does generate some waste heat.


Have never seen a battery explode or one that had exploded. I'm sure I came
very close, many decades ago, when jumping a 6 volt car with a 12 volt car.
Have only seen a few starters burnt up from over cranking either. Most
people know not to do it.


When I was a kid my dad had a Ford station wagon. It went through
starters like crazy, and was hard to start. He went to a junkyard and
bought a 6 volt starter and battery cables for a few bucks. He put them
in the 12 volt Ford station wagon. After that, it only took one try to
start it because it turned over much faster.


Voltage and current are not mutually exclusive If current draw is high
enough then it drops the voltage. Either from resistance or lack of battery
capacity. If ignition voltage is dropped enough the plugs don't fire.
However it happens it's the heat that kills. That certainly wouldn't be any
kind of an engine a person could use for a year round driver around here.


That's one bad thing about the sunny south. You rarely get any
warning that a car battery is getting old. You stick the key in and it
doesn't turn start. Sometimes the solenoid doesn't even click, even
though you had driven a while and shut it off minutes earlier.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

David Brodbeck wrote:

Homer J Simpson wrote:
"David Brodbeck" wrote in message
t...

Had one explode on a travel trailer once, too. The battery was in a
plastic battery box on the front A-frame and had been on trickle charge
for about three months. This was in the middle of winter. It threw
shrapnel a foot or two on either side.

Froze up?

Probably. To say that the battery chargers in RV power converters are
often poorly designed would be, perhaps, too kind.


All of the RV power converters I've had were nothing more than the
transformer, a pair of diodes and a power switch. The were intended to
run 12 VDC motors and lights, so they had no filter capacitors They
were not intended to charge a battery.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

David Brodbeck wrote:

Michael A. Terrell wrote:
My last car had pinholes in that corner of the hood The battery
exploded when my Dad owned it.

Oddly, the hood on mine is OK. This suggests one of two things:

- The battery explosion was the result of a collision, and the hood was
replaced. I don't think it's that, because the cowl area near the
battery is rusty, and any collision damage would have affected it, too.

- The battery explosion happened with the hood up. Jump-starting
accident, maybe?


Either that or it was hosed out immediately, before the acid could
start attacking the metal. The paint under a lot of hoods is poor,
because most car owners never look under the hood, and when they do,
they rarely look up. That paint has lots of tiny pinholes, and it
doesn't take long for the acid to attack the metal through the holes.


Another thing that puzzles me is the current battery has a tendency to
weep liquid out of the cell covers. Normally I'd assume this was
boil over due to overcharging, but the charging voltage is normal.


Maybe the emergency vent is plugged? Some batteries have a small
channel that runs across the top of the battery to vent pressure, to
prevent an explosion.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Michael A. Terrell wrote:
"Dave Plowman (News)" wrote:

In article tqvSh.13654$Rg2.5267@trndny02,
James Sweet wrote:

Well my car with a relatively small 2.3L 4 cylinder engine has a starter
motor rated at 1.4KW, so well over 100A. I'm not sure if this is typical
but the starter is powerful enough to move the car if I put it in gear
and turn the key. I suspect larger engines typically have even more
powerful starters.

The current needed depends on several things - notably how much friction
in the engine which varies between cold and hot.



I have never looked at the specs on the electrical system on a bike.
Years ago any car starter that drew over 70 amps, no load was considered
defective. That's why I asked.




Well yeah, 70 amps no-load is a huge draw. Hundreds of amps under load
is not uncommon though. Big difference.

Michael A. Terrell wrote:
When I was a kid my dad had a Ford station wagon. It went through
starters like crazy, and was hard to start. He went to a junkyard and
bought a 6 volt starter and battery cables for a few bucks. He put them
in the 12 volt Ford station wagon. After that, it only took one try to
start it because it turned over much faster.

I've heard this is a common hack for Wankel engine conversions on VW
Beetles. A stock VW starter won't crank a Wankel fast enough to fire.
But if you run a 6 volt starter off 12 volts, it will.

David Brodbeck wrote:

Michael A. Terrell wrote:
When I was a kid my dad had a Ford station wagon. It went through
starters like crazy, and was hard to start. He went to a junkyard and
bought a 6 volt starter and battery cables for a few bucks. He put them
in the 12 volt Ford station wagon. After that, it only took one try to
start it because it turned over much faster.

I've heard this is a common hack for Wankel engine conversions on VW
Beetles. A stock VW starter won't crank a Wankel fast enough to fire.
But if you run a 6 volt starter off 12 volts, it will.


I never worked on VWs, but I have a neighbor and a friend who are VW
fanatics. I preferred mid '60s Pontiacs, and I always kept the shop's
service trucks on the road. From a Corvair van, all the way to a Chevy
step van. There was even a 53 Ford panel truck at one shop.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

James Sweet wrote:

Michael A. Terrell wrote:

I have never looked at the specs on the electrical system on a bike.
Years ago any car starter that drew over 70 amps, no load was considered
defective. That's why I asked.

Well yeah, 70 amps no-load is a huge draw. Hundreds of amps under load
is not uncommon though. Big difference.


I could test a car starter on my electronics bench at one time. The
adjustable, regulated DC bench supply would put out over 75 amps
continuous, and 95 amps short term. I used to rebuild my starters and
alternators. Less than $10 in parts, and a half hour, and I was back in
business. Brushes or bearings were cheap and easy to replace. Open
windings meant that the unit was scrap.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Michael A. Terrell" wrote in message
...
David Brodbeck wrote:

Homer J Simpson wrote:
"David Brodbeck" wrote in message
t...

Had one explode on a travel trailer once, too. The battery was in a
plastic battery box on the front A-frame and had been on trickle
charge
for about three months. This was in the middle of winter. It threw
shrapnel a foot or two on either side.

Froze up?

Probably. To say that the battery chargers in RV power converters are
often poorly designed would be, perhaps, too kind.


All of the RV power converters I've had were nothing more than the
transformer, a pair of diodes and a power switch. The were intended to
run 12 VDC motors and lights, so they had no filter capacitors They
were not intended to charge a battery.


All of the 'off-vehicle' battery chargers that I've seen here in the UK, are
just a transformer, couple of diodes and a fuse and meter. I've never even
thought about them having filter caps. I don't actually see why they would
need them. The battery being charged represents a very low impedance cap
(electrically) anyway, doesn't it ? For this reason, all of the electronic
circuitry in modern cars, runs quite happily, with not a sign of a big cap
anywhere, including on the alternator output, to where the battery is glued
pretty much directly. I've also read somewhere I think, that charging with a
'pulsy' waveform is good for breaking down inter-plate sulphation. Could be
wrong on any of this - auto electrics not really my subject, but have owned
and maintained cars for more years than I care to remember.

Interesting about the exploding batteries. I'm sure that temperature must be
a big factor in this. I've been in Florida when there has been sustained
heat. The UK does get that hot, but only for a day or so at a time. I have
never had a car battery explode on me, and I can't think of ever having
heard of any friends or colleagues that have either. On the other hand, we
do get sustained periods of cold ( or at least we used to ) in the winter,
and I don't recall ever having heard of a battery freezing. Looking around
on the net, the freezing point of sulphuric acid, seems to be around
the -20C mark depending on concentration, so that might be why batteries
don't typically freeze here, but what happens when these things are in use
up in the north of Canada or wherever ? Do freeze inhibitors have to be
added ? Does a frozen battery cease to produce any current at all, and does
it recover if left to unfreeze ?

Arfa

On Mon, 09 Apr 2007 19:15:14 GMT "Michael A. Terrell"
wrote in Message id:
:

I had to install #1 welding
cable on the customized 389 8 cylinder engine in my '66 GTO that had
over 220 pounds compression. ^^^^^^

OK, I'm jealous.

In article ,
Arfa Daily wrote:
All of the 'off-vehicle' battery chargers that I've seen here in the UK,
are just a transformer, couple of diodes and a fuse and meter.

[Sucks breath through teeth]

Even my 10 year old Halfords one is a bit more sophisticated than that. ;-)

Most decent modern ones will also change to a float charge when the
battery is fully charged. So called 'sealed' - actually low maintenance
types - don't like being left to gas heavily as once was the norm.

[snip]

Interesting about the exploding batteries. I'm sure that temperature
must be a big factor in this. I've been in Florida when there has been
sustained heat. The UK does get that hot, but only for a day or so at a
time. I have never had a car battery explode on me, and I can't think
of ever having heard of any friends or colleagues that have either.

It used to be fairly common when garages had battery charging areas -
mechanics would plug or unplug one from the communal charger and a spark
would do the rest. But H&S regs would probably make sure any such area
these days was properly ventilated. But I'd agree with you - I've not
known one explode on a car.

On the other hand, we do get sustained periods of cold ( or at least we
used to ) in the winter, and I don't recall ever having heard of a
battery freezing. Looking around on the net, the freezing point of
sulphuric acid, seems to be around the -20C mark depending on
concentration, so that might be why batteries don't typically freeze
here, but what happens when these things are in use up in the north of
Canada or wherever ? Do freeze inhibitors have to be added ? Does a
frozen battery cease to produce any current at all, and does it recover
if left to unfreeze ?

I remember stories long time ago about those in Scandinavian countries etc
with severe winters taking the battery indoors at night. That would be a
pain these days with all the memories on a modern car.

--
*Honk if you love peace and quiet.

Dave Plowman London SW
To e-mail, change noise into sound.

Arfa Daily wrote:
On the other hand, we
do get sustained periods of cold (or at least we used to) in the winter,
and I don't recall ever having heard of a battery freezing. Looking around
on the net, the freezing point of sulphuric acid, seems to be around
the -20C mark depending on concentration, so that might be why batteries
don't typically freeze here, but what happens when these things are in use
up in the north of Canada or wherever ? Do freeze inhibitors have to be
added ? Does a frozen battery cease to produce any current at all, and does
it recover if left to unfreeze ?

Arfa

Actually, the freezing point of a fully charged battery is much lower
than that. According to the well-respected and independent site
www.batteryfaq.org, the electrolyte in a fully charged battery freezes
at -77F (-67C). A freezing point of -20C represents an almost fully
discharged battery. I'm also under the impression (though I haven't a
reference at the moment) that when it freezes, it first turns slushy,
and only at somewhat colder temps does it turn solid. However,
apparently when it gets cold enough to turn solid, it will crack the
case, ruining the battery.

Also pertinent to your question - when a battery gets cold, its terminal
voltage drops, so it won't crank a car engine as well. Unfortunately a
car engine is harder to crank when it is cold, so these two things are
moving in opposite directions, with the result that a car can be very
hard to start on a cold morning. When I lived in central Maine in the
late 60's, I had a Chevy Blazer with a sizable V-8 engine. I remember
that I wrapped an electric heat-tape around the battery, and wrapped the
whole thing in a thin insulation blanket. When the overnight temp was
expected to be -25F or lower, I would run an extension cord out to the
car and plug in the heat tape - it was the only way I could be sure it
would start. I was quite often the only one in the entire student
apartment complex who could start a car in the morning, so I would use
jumper cables to start two other cars, and then go off to school. In a
rare show of social co-operation, the drivers of each of those two cars
would usually jump start two others, and before long the entire
apartment complex was up and running.

In places like Fairbanks, there are electrical outlets on the parking
meters ...

Bill Jeffrey

Arfa Daily wrote:

"Michael A. Terrell" wrote in message
...
David Brodbeck wrote:

Homer J Simpson wrote:
"David Brodbeck" wrote in message
t...

Had one explode on a travel trailer once, too. The battery was in a
plastic battery box on the front A-frame and had been on trickle
charge
for about three months. This was in the middle of winter. It threw
shrapnel a foot or two on either side.

Froze up?

Probably. To say that the battery chargers in RV power converters are
often poorly designed would be, perhaps, too kind.


All of the RV power converters I've had were nothing more than the
transformer, a pair of diodes and a power switch. The were intended to
run 12 VDC motors and lights, so they had no filter capacitors They
were not intended to charge a battery.


All of the 'off-vehicle' battery chargers that I've seen here in the UK, are
just a transformer, couple of diodes and a fuse and meter. I've never even
thought about them having filter caps.


Some people try to use the "Power Converter" top power electronics,
then complain when the smoke pours out. The high ripple and high peak
voltages destroy cheap stuff.


I don't actually see why they would
need them. The battery being charged represents a very low impedance cap
(electrically) anyway, doesn't it ? For this reason, all of the electronic
circuitry in modern cars, runs quite happily, with not a sign of a big cap
anywhere, including on the alternator output, to where the battery is glued
pretty much directly.


These devices are used while parked, to keep the load off the
vehicles battery and electrical system.


I've also read somewhere I think, that charging with a
'pulsy' waveform is good for breaking down inter-plate sulphation. Could be
wrong on any of this - auto electrics not really my subject, but have owned
and maintained cars for more years than I care to remember.


I have seen a lot of conflicting views on the subject but a quality
car battery should last five years or more, with proper use and care.


Interesting about the exploding batteries. I'm sure that temperature must be
a big factor in this. I've been in Florida when there has been sustained
heat. The UK does get that hot, but only for a day or so at a time. I have
never had a car battery explode on me, and I can't think of ever having
heard of any friends or colleagues that have either. On the other hand, we
do get sustained periods of cold ( or at least we used to ) in the winter,
and I don't recall ever having heard of a battery freezing. Looking around
on the net, the freezing point of sulphuric acid, seems to be around
the -20C mark depending on concentration, so that might be why batteries
don't typically freeze here, but what happens when these things are in use
up in the north of Canada or wherever ? Do freeze inhibitors have to be
added ? Does a frozen battery cease to produce any current at all, and does
it recover if left to unfreeze ?


I spent a year in Alaska back in the '70s. We had small electric
heaters that wrapped around the battery to prevent freezing. We also had
dipstick heaters to keep the oil thin enough to start, and a lower
heater hose heater that kept the coolant above its freezing point. You
were limited to a single 20 amp, 120 volt circuit to protect your
vehicle, and you needed a permit to use the outdoor outlets on the Army
base. It dropped below -20 F quite often, and sometimes low enough that
the battery would still freeze.

If the electrolyte does a full, hard freeze the battery case cracks.
A little less than that can distort the plates and short them out, or
break the connections at the top where the connect between cells. I
have autopsied a number of damaged batteries before turning in the scrap
lead. Its amazing the damage a little frozen electrolyte can do to a
lead acid battery.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

JW wrote:

On Mon, 09 Apr 2007 19:15:14 GMT "Michael A. Terrell"
wrote in Message id:
:

I had to install #1 welding
cable on the customized 389 8 cylinder engine in my '66 GTO that had
over 220 pounds compression. ^^^^^^

OK, I'm jealous.


Don't be, I had to get rid of both of them about 20 years ago but
they were fun while I owned, and drove one of them. (the other was a
parts car)

There was a mistake on the engine number I took the crankshaft out
of. I had it acid cleaned and it measured less than .0005" wear so I
used it, only to find out the engine was an earlier version, and
wouldn't bolt to the torque converter. On top of that, it was from a 421
engine, not a 389. That thing would idle at about 300 RPM, according to
the factory tach.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Michael A. Terrell" wrote in message
...
Arfa Daily wrote:

"Michael A. Terrell" wrote in message
...
David Brodbeck wrote:

Homer J Simpson wrote:
"David Brodbeck" wrote in message
t...

Had one explode on a travel trailer once, too. The battery was in
a
plastic battery box on the front A-frame and had been on trickle
charge
for about three months. This was in the middle of winter. It
threw
shrapnel a foot or two on either side.

Froze up?

Probably. To say that the battery chargers in RV power converters are
often poorly designed would be, perhaps, too kind.


All of the RV power converters I've had were nothing more than the
transformer, a pair of diodes and a power switch. The were intended to
run 12 VDC motors and lights, so they had no filter capacitors They
were not intended to charge a battery.


All of the 'off-vehicle' battery chargers that I've seen here in the UK,
are
just a transformer, couple of diodes and a fuse and meter. I've never
even
thought about them having filter caps.


Some people try to use the "Power Converter" top power electronics,
then complain when the smoke pours out. The high ripple and high peak
voltages destroy cheap stuff.


I don't actually see why they would
need them. The battery being charged represents a very low impedance cap
(electrically) anyway, doesn't it ? For this reason, all of the
electronic
circuitry in modern cars, runs quite happily, with not a sign of a big
cap
anywhere, including on the alternator output, to where the battery is
glued
pretty much directly.


These devices are used while parked, to keep the load off the
vehicles battery and electrical system.


I've also read somewhere I think, that charging with a
'pulsy' waveform is good for breaking down inter-plate sulphation. Could
be
wrong on any of this - auto electrics not really my subject, but have
owned
and maintained cars for more years than I care to remember.


I have seen a lot of conflicting views on the subject but a quality
car battery should last five years or more, with proper use and care.


Interesting about the exploding batteries. I'm sure that temperature must
be
a big factor in this. I've been in Florida when there has been sustained
heat. The UK does get that hot, but only for a day or so at a time. I
have
never had a car battery explode on me, and I can't think of ever having
heard of any friends or colleagues that have either. On the other hand,
we
do get sustained periods of cold ( or at least we used to ) in the
winter,
and I don't recall ever having heard of a battery freezing. Looking
around
on the net, the freezing point of sulphuric acid, seems to be around
the -20C mark depending on concentration, so that might be why batteries
don't typically freeze here, but what happens when these things are in
use
up in the north of Canada or wherever ? Do freeze inhibitors have to be
added ? Does a frozen battery cease to produce any current at all, and
does
it recover if left to unfreeze ?


I spent a year in Alaska back in the '70s. We had small electric
heaters that wrapped around the battery to prevent freezing. We also had
dipstick heaters to keep the oil thin enough to start, and a lower
heater hose heater that kept the coolant above its freezing point. You
were limited to a single 20 amp, 120 volt circuit to protect your
vehicle, and you needed a permit to use the outdoor outlets on the Army
base. It dropped below -20 F quite often, and sometimes low enough that
the battery would still freeze.

If the electrolyte does a full, hard freeze the battery case cracks.
A little less than that can distort the plates and short them out, or
break the connections at the top where the connect between cells. I
have autopsied a number of damaged batteries before turning in the scrap
lead. Its amazing the damage a little frozen electrolyte can do to a
lead acid battery.



Thanks all. Very informative stuff. Sorry to cause the teeth sucking Dave
( don't do it too much - you might get mistaken for Gordon Brown and we
wouldn't want that ... ;~} ). I must admit that I've had my Halfords'
charger since I was a kid with my first Moggy Minor, and it's still going
strong. Haven't looked inside one for years, so I'll take your word for it
that we now have to charge brute force lead acid batteries with an
electronically controlled feather touch. But how does that stack up against
charging it on the vehicle with an alternator ? That hasn't got much more in
it than it ever had, has it ? Three phase bridge, pretty basic voltage
regulator, yes ?? Still fundamentally a brute force charging device, relying
on the battery to self smooth the charging voltage, without help from caps,
and to stop drawing charging current when it's had enough, much like in the
old days. There are plenty of 10 or more year old vehicles out there with
very conventional alternators on them. Is there supposedly an issue then,
when a new generation sealed maintenance free battery is fitted to one of
these cars ?

Arfa

Arfa Daily wrote:

Thanks all. Very informative stuff. Sorry to cause the teeth sucking Dave
( don't do it too much - you might get mistaken for Gordon Brown and we
wouldn't want that ... ;~} ). I must admit that I've had my Halfords'
charger since I was a kid with my first Moggy Minor, and it's still going
strong. Haven't looked inside one for years, so I'll take your word for it
that we now have to charge brute force lead acid batteries with an
electronically controlled feather touch. But how does that stack up against
charging it on the vehicle with an alternator ? That hasn't got much more in
it than it ever had, has it ? Three phase bridge, pretty basic voltage
regulator, yes ?? Still fundamentally a brute force charging device, relying
on the battery to self smooth the charging voltage, without help from caps,
and to stop drawing charging current when it's had enough, much like in the
old days. There are plenty of 10 or more year old vehicles out there with
very conventional alternators on them. Is there supposedly an issue then,
when a new generation sealed maintenance free battery is fitted to one of
these cars ?

Arfa


I'm waiting to see the new cars with a 42 volt electrical system, and
how they handle starting in less than ideal situations.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Arfa Daily" wrote in message
news
Interesting about the exploding batteries. I'm sure that temperature must
be a big factor in this.

In Alaska, battery heaters are normal, and engine heaters essential.

Michael A. Terrell wrote:
I'm waiting to see the new cars with a 42 volt electrical system, and
how they handle starting in less than ideal situations.

I suspect they'll start more easily, for the same reason 12 volt cars
start more easily than 6 volt ones. Higher voltage means lower current,
and lower current means lower resistive losses in the cables and
connections.