Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #41   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 558
Default Battery question

On Sun, 16 Mar 2008 19:05:47 -0700, Gunner Asch
wrote:

the only time Ive shorted a battery in any major way, was when Gloria
Maxwell decided to Cowboy Up! in the passenger side rear seat of a VW
bug. About the third really good bounce she made on the old joystick
and the bottom of the seat shorted out across the battery terms. Had
to peel her off during her Happy Moment(s) when I smelled smoke and my
ass started burning.

Ripped out the backseat and nearly caused a brush fire


Now if you could only track down the doof who figured that little
plastic positive terminal cover was worthless and threw it away,
instead of placing it on the battery as intended...

My car, there would have been a big sheet of Plexi or Lexan over the
whole battery, or it would have been moved - Inside the passenger
compartment is NOT a smart place to put a hydrogen gas generator with
a half gallon of HCL acid inside.

-- Bruce --

  #42   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 88
Default Battery question

Bruce L. Bergman wrote:
On Sun, 16 Mar 2008 19:05:47 -0700, Gunner Asch
wrote:

the only time Ive shorted a battery in any major way, was when Gloria
Maxwell decided to Cowboy Up! in the passenger side rear seat of a VW
bug. About the third really good bounce she made on the old joystick
and the bottom of the seat shorted out across the battery terms. Had
to peel her off during her Happy Moment(s) when I smelled smoke and my
ass started burning.

Ripped out the backseat and nearly caused a brush fire


Now if you could only track down the doof who figured that little
plastic positive terminal cover was worthless and threw it away,
instead of placing it on the battery as intended...

My car, there would have been a big sheet of Plexi or Lexan over the
whole battery, or it would have been moved - Inside the passenger
compartment is NOT a smart place to put a hydrogen gas generator with
a half gallon of HCL acid inside.

-- Bruce --
T'aint HCL----it's H2SO4---but you knew that--!!

  #43   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 1,224
Default Battery question

On Mon, 17 Mar 2008 19:24:17 -0700, Bruce L. Bergman
wrote:

On Sun, 16 Mar 2008 19:05:47 -0700, Gunner Asch
wrote:

the only time Ive shorted a battery in any major way, was when Gloria
Maxwell decided to Cowboy Up! in the passenger side rear seat of a VW
bug. About the third really good bounce she made on the old joystick
and the bottom of the seat shorted out across the battery terms. Had
to peel her off during her Happy Moment(s) when I smelled smoke and my
ass started burning.

Ripped out the backseat and nearly caused a brush fire


Now if you could only track down the doof who figured that little
plastic positive terminal cover was worthless and threw it away,
instead of placing it on the battery as intended...

My car, there would have been a big sheet of Plexi or Lexan over the
whole battery, or it would have been moved - Inside the passenger
compartment is NOT a smart place to put a hydrogen gas generator with
a half gallon of HCL acid inside.

-- Bruce --

No HCl in any car battery I ever owned.
Gerry :-)}
London, Canada
  #44   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 72
Default Battery question

On Mon, 17 Mar 2008 22:10:47 GMT, "Carl Byrns"
wrote:


"SteveB" wrote in message
...

"Vaughn Simon" wrote

As far as charging goes, most batteries will tolerate a 6 amp charge,
but if you have any doubts, go with 2 amps.


But even a 2 amp "dumb" charger will eventually overcharge and ruin
your battery if left connected and forgotten. The best way I have found
to store any lead acid battery is by leaving it connected to a special
"float" charger. In any case, the battery should always be stored fully
charged.

Vaughn



My charger is a Dayton. A pretty decent charger I think. It has settings
for starting, 10, 6, and 2 amps. But there's a needle to show how many
amps it is actually charging at. You can put it on ten, and the needle
might point to only six. Then as it charges up, the needle drops to zero.
Looks to me like it senses the charge, and tapers off.

Steve


Next time you charge a battery, hook up a voltmeter and watch the volts go
up as the amps go down. High voltages can damage the battery. A smart
charger controls both the charging current and voltage.

-Carl


While there is no question that high voltage will damage a battery, in
real life most battery chargers will be perfectly suitable since a
battery's internal resistance increases as the battery is charged
making the system is pretty much self limiting.

Try connecting a volt meter and an amp meter in parallel with the
battery charger. Turn the charger up to about a 10 amps charging
current and watch the volt meter. As voltage climbs the amperage
decreases. With about a 10 amp initial charging current by the time
the battery voltage reaches about 13.5 volts the current will have
decreased to about 1 or 2 amps. Hardly a battery killing combination.

To put the battery charging cycle in prospective, A "3 stage smart
charger" charges the battery to about 14.2 volts (depends on type of
battery) before dropping back to about 13.4 for the bulk charge.

Bruce-in-Bangkok
(correct email address for reply)
  #45   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 271
Default Battery question

On Tue, 18 Mar 2008 10:07:45 +0700, Bruce in Bangkok wrote:
....
While there is no question that high voltage will damage a battery, in
real life most battery chargers will be perfectly suitable since a
battery's internal resistance increases as the battery is charged making
the system is pretty much self limiting.


Internal resistance vs. charge depends a bit on battery type and
history. [1][2] For lead-acid batteries, internal resistance
decreases (not increases) as charge goes up. For typical car
battery chargers, current drops as charge approaches 100% because
the difference between charger voltage and battery voltage drops
toward zero. Open-circuit charger voltage and charger resistance
will be the main limiting factors.

Try connecting a volt meter and an amp meter in parallel with the
battery charger. Turn the charger up to about a 10 amps charging current
and watch the volt meter. As voltage climbs the amperage decreases. With
about a 10 amp initial charging current by the time the battery voltage
reaches about 13.5 volts the current will have decreased to about 1 or 2
amps. Hardly a battery killing combination.

....

[1] http://www.arttec.net/Solar_Mower/4_...20Charging.pdf
in section "Lead-acid Internal Resistance and SOC" at bottom of 4th page
says "A fully discharged lead-acid cell has virtually no sulfuric
acid in its almost pure water electrolyte" [so would have high resistance]

[2] Near end of http://www.batteryuniversity.com/partone-22.htm ,
the paragraph before Figure 6 (resistance vs. voltage) says
"The resistance of lead acid goes up with discharge", etc.
-jiw


  #46   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 12,924
Default Battery question


"Bruce L. Bergman" wrote:

On Sun, 16 Mar 2008 19:05:47 -0700, Gunner Asch
wrote:

the only time Ive shorted a battery in any major way, was when Gloria
Maxwell decided to Cowboy Up! in the passenger side rear seat of a VW
bug. About the third really good bounce she made on the old joystick
and the bottom of the seat shorted out across the battery terms. Had
to peel her off during her Happy Moment(s) when I smelled smoke and my
ass started burning.

Ripped out the backseat and nearly caused a brush fire


Now if you could only track down the doof who figured that little
plastic positive terminal cover was worthless and threw it away,
instead of placing it on the battery as intended...

My car, there would have been a big sheet of Plexi or Lexan over the
whole battery, or it would have been moved - Inside the passenger
compartment is NOT a smart place to put a hydrogen gas generator with
a half gallon of HCL acid inside.

-- Bruce --



Come on Bruce! I's well know that the Germans were still sore over
losing WW-II, and they were just trying to get even with cheap imported
rolling firebombs.

--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
* drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic.

http://improve-usenet.org/index.html
  #47   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 72
Default Battery question

On Mon, 17 Mar 2008 23:46:20 -0500, James Waldby wrote:

On Tue, 18 Mar 2008 10:07:45 +0700, Bruce in Bangkok wrote:
...
While there is no question that high voltage will damage a battery, in
real life most battery chargers will be perfectly suitable since a
battery's internal resistance increases as the battery is charged making
the system is pretty much self limiting.


Internal resistance vs. charge depends a bit on battery type and
history. [1][2] For lead-acid batteries, internal resistance
decreases (not increases) as charge goes up. For typical car
battery chargers, current drops as charge approaches 100% because
the difference between charger voltage and battery voltage drops
toward zero. Open-circuit charger voltage and charger resistance
will be the main limiting factors.

Try connecting a volt meter and an amp meter in parallel with the
battery charger. Turn the charger up to about a 10 amps charging current
and watch the volt meter. As voltage climbs the amperage decreases. With
about a 10 amp initial charging current by the time the battery voltage
reaches about 13.5 volts the current will have decreased to about 1 or 2
amps. Hardly a battery killing combination.

...

[1] http://www.arttec.net/Solar_Mower/4_...20Charging.pdf
in section "Lead-acid Internal Resistance and SOC" at bottom of 4th page
says "A fully discharged lead-acid cell has virtually no sulfuric
acid in its almost pure water electrolyte" [so would have high resistance]

[2] Near end of http://www.batteryuniversity.com/partone-22.htm ,
the paragraph before Figure 6 (resistance vs. voltage) says
"The resistance of lead acid goes up with discharge", etc.
-jiw



Of course you are correct and electricity flows from negative to
positive and transistors work because of "electronic holes".

But the average user has a bit of trouble visualizing that so the
explanation that the internal resistance increases and thus the
charging current decreases (which it does) is easily understood. It
may not be correct but it does explain the action of the usual
transformer battery charger in terms that the average user can relate
to.








Bruce-in-Bangkok
(correct email address for reply)
  #48   Report Post  
Posted to rec.crafts.metalworking
Joe Joe is offline
external usenet poster
 
Posts: 60
Default Battery question

On Tue, 18 Mar 2008 10:07:45 +0700, Bruce in Bangkok
wrote:

[snip]
Try connecting a volt meter and an amp meter in parallel with the
battery charger. Turn the charger up to about a 10 amps charging
current and watch the volt meter. As voltage climbs the amperage
decreases. With about a 10 amp initial charging current by the time
the battery voltage reaches about 13.5 volts the current will have
decreased to about 1 or 2 amps. Hardly a battery killing combination.

[snip]

I would be very careful about connecting an amp meter in parallel with
any battery charger. At the least, you will have to replace a fuse
right away. At worst, all of the magic smoke will escape from either
the meter or the charger (or both), or you may find yourself rushing
towards the nearest fire extinguisher.

Joe
  #49   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 3,444
Default Battery question

Bruce in Bangkok wrote:
(...)
But the average user has a bit of trouble visualizing that so the
explanation that the internal resistance increases and thus the
charging current decreases (which it does) is easily understood. It
may not be correct but it does explain the action of the usual
transformer battery charger in terms that the average user can relate
to.


It *is* Ohm's Law but you are changing the wrong variable.
Current equals voltage divided by resistance. The difference in voltage between charger
and battery drives current way more than does the change in the batterys internal
resistance.

A given SLA might have an internal resistance that halves when the battery is taken from
'discharged' to 'fully charged' state. However that same battery is likely to experience
a 15:1 decrease in current flow at the same time, because of the voltage difference
between the charger and battery.

I think it would be as easy for the average user to visualize (a 'decrease in voltage
difference' causing a charge current decrease) as it would be for them to visualize (a
'decrease in internal resistance' causing a decrease in charge current). That is fortunate
because the first cause really happens and the second cause is completely backwards from
reality.


--Winston
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Another Car Battery question Ivan Vegvary Metalworking 31 February 6th 08 04:26 AM
Battery Question Jim Thompson Electronic Schematics 12 May 12th 07 08:40 AM
12V dry battery question TimPerry Electronics Repair 2 March 14th 06 04:01 PM
battery question SteveB Metalworking 5 December 11th 05 05:09 PM
alarm system battery backup, battery replacement question Michael Baugh Home Repair 1 June 19th 04 04:35 PM


All times are GMT +1. The time now is 09:36 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"