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post #1 of (permalink) Old 07-31-2003, 09:55 AM Thread Starter
 
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Battery help

Can anyone explain what has happened inside a battery when it won't charge? Tuesday I was going to drive the jeep for the first time in several days and the battery was dead. I connected a charger to it for about 30 minutes and then used the cranking position on the charger to start the jeep. I drove it for about 30 minutes running some errands, shutting it off and cranking it 4 or 5 times. Yesterday, I decided to rewire the alternator since charging depended too much on RPMs and not load. I didn't try to start the jeep, just disconnected the battery. When I was finished, I tried to start it and the battery was dead again. I tried charging it and it wouldn't charge. I trickle charged it overnight and it still won't start the jeep. I disconnected everything again and checked it with a voltmeter and got a reading of 10.4 volts with a Fluke. I realize the battery is bad, just not how it went bad so sudden.
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post #2 of (permalink) Old 07-31-2003, 10:28 AM
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Re: Battery help

1. The electrolytic is toast...
2. Or the plates are sulfated.
3. Closer plates in the same size case mean more CCA's
4. That sells batteries,
5. And puts plates closer so they bang together under vibration,
6. And the junk falls to the bottom of the case,
7. Providing a nice good little path of resistance,
8. Between positive and negative,
9. Causing the battery to die...
10. As in all things, it can happen:[*]Quickly [*]Slowly, this is a shallow charge.
11. In any case, the battery drains itself.
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post #3 of (permalink) Old 07-31-2003, 10:39 AM
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Re: Battery help

80% of all battery failure is related to sulfation build-up. This build up occurs when the sulfur molecules in the electrolyte (battery acid) become so deeply discharged that they begin to coat the battery's lead plates. Before long the plates become so coated that the battery dies. The causes of sulfation are numerous.
Batteries sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.
Batteries are stored without some type of energy input.
"Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.
Undercharging of a battery, to charge a battery (let''s say) to 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by the incomplete charging cycle.
Heat of 100 plus F., increases internal discharge. As temperatures increase so does internal discharge. A new fully charged battery left sitting 24 hours a day at 110 degrees F for 30 days would most likely not start an engine.
Low electrolyte level -*battery plates exposed to air will immediately sulfate.
Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good. See the section on battery charging.
Cold weather is also hard on the battery. the chemistry does not make the same amount of energy as a warm battery. A deeply discharged battery can freeze solid in sub zero weather.
Parasitic drain is a load put on a battery with the key off. More info on parasitic drain will follow in this document.

It has to be here somewhere.

Scott
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post #4 of (permalink) Old 07-31-2003, 11:03 AM Thread Starter
 
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Re: Battery help

Thanks for the replies. I now have a much greater understanding of why batteries go bad. I always charge the batteries in my bass boat after fishing. I also connect an automatic trickle charger to keep them charged. The charger maintains all 3 batteries at 12.8 volts.
Now my next question. Would it be a good idea to trickle charge an automotive battery when the vehicle isn't driven very often?
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post #5 of (permalink) Old 07-31-2003, 07:49 PM
 
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Re: Battery help

I've never trickle-charged any of my batteries and my vehicles don't get driven very often, especially my '71 Ford which is only driven once every 3 weeks on average. The battery in the '71 is 11 years old and has not given me any trouble although I can tell that it is gradually getting weaker.
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post #6 of (permalink) Old 07-31-2003, 08:54 PM
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Re: Battery help

Have any of you had any experience with the SOLARGIZER chargers and maintainers? The only things I have heard are good, but anyone who spent the money on one may be a little biased, since they cost so much.
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post #7 of (permalink) Old 08-03-2003, 07:02 AM
 
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Re: Battery help

</font><blockquote><font class="small">In reply to:</font><hr />
I disconnected everything again and checked it with a voltmeter and got a reading of 10.4 volts with a Fluke.

[/ QUOTE ]
Its more likely that one cell shorted out then the battery sulfated. (each cell has 2.1 volts)

</font><blockquote><font class="small">In reply to:</font><hr />
Would it be a good idea to trickle charge an automotive battery when the vehicle isn't driven very often?


[/ QUOTE ]
I would keep an eye on the battery voltage with your VOM.
A fully charged battery will have 12.6V. The voltage should never go below 12.1V
Put a charger on it when the voltage goes below 12.3. A goud battery should hold a charge for about 5 weeks. If it doesn't. Perform a load test on a fully charged battery to check for sulfation. If the battery is OK, then check the eletrical system for a parasitic draw.

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