"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.