"BJohnson11" (brettjohnson01)
09/16/2013 at 12:10 • Filed to: None
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"BJohnson11" (brettjohnson01)
09/16/2013 at 12:10 • Filed to: None | 0
| 8 |
So my truck has seemed to develop quite the battery drain. I had to jump it on Thursday, and once it was running, I let the battery charge up. Using a voltmeter, I was able to determine that the alternator was in fact charging the battery. When I tried to start it Friday morning though, it didn't have enough juice to start. Fast forward to Saturday night, and the battery was at 2 volts! 2 volts! I'm borrowing a battery charger from a friend and once it's charged up, I'll get it load tested at NAPA, but in the mean time, what can I do to try to diagnose the problem?
And no, the lights, radio, etc aren't on. And this is somehow a recent development. Also to note, but I find it strange that the cable running from the negative end of the battery only grounds to the block—there is no ground to the chassis. Is that strange? I'd think that it would ground to the chassis too no?
TheLOUDMUSIC- Put it in H!
> BJohnson11
09/16/2013 at 12:16 |
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Check your alternator. My dad's van had a problem with the coil shorting out or something. IDK anything other than its was fixed with a new alternator, but it charged the battery normally. Or, you could just put a main cutoff switch in it, hide it, maybe in a toolbox to fool thieves.
McMike
> BJohnson11
09/16/2013 at 12:23 |
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TEST #1: How "full" does the battery get? Charge it overnight with a good (not trickle) charger, disconnect for 20 min, then check the voltage. Is it 12.8? Is is 12.1? This will tell you if your battery needs replacement.
TEST #2: What were the volts when your alternator was charging the battery at a fast idle (1500-2000rpm)? If it's not 13.0 or higher, you may have a charging issue.
TEST #3: If the battery and charging system check out, then you need to start looking for a parasitic drain. You'll need to use an ammeter to measure the draw from your battery. With all the lights/radio off, measure the draw and then start pulling fuses one-by-one to see the draw drops with a particular fuse if you can identify the guilty circuit. 0.05 amps is about normal.
Also, a 2 volt battery? it's probably dead, but perform #1 to be sure.
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BJohnson11
> McMike
09/16/2013 at 12:38 |
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Thanks! Yea when running, it would get up to 13.5-13.8 with the engine revving around 2-3 grand. So I don't think it's an alternator.
Thanks for the advice. For Test #3, does the battery need to be fully charged to do the test? I have another battery laying around that isn't fully charged (maybe 10 volts) but also doesn't fit the terminals on my truck perfectly, but I'm thinking I could hook it up and still pull fuses?
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BJohnson11
> TheLOUDMUSIC- Put it in H!
09/16/2013 at 12:39 |
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I was considering a main cut off switch as an act of desparation, but I'd rather not do that.
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McMike
> BJohnson11
09/16/2013 at 12:56 |
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I suppose you could use an older battery for test #3, but a good one is better.
Check out how full your battery gets first before jumping to #3. You didn't throw out a voltage reading when you said "I let the battery charge up."
Cleaning terminals is always a good thing to start with before tackling these tests.
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BJohnson11
> McMike
09/16/2013 at 12:59 |
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Well on Thursday the battery charged up to over 12v after I turned the truck off. But then it sat until Saturday night, and when I checked the voltage, it was down to 2 volts. It's on the charger now though so we'll see if it can get back up. I do know that a small parasitic drain will have exaggerated effects on a bad battery, so I'm not ruling the battery out by any means.
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McMike
> BJohnson11
09/16/2013 at 13:42 |
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You could also disconnect the negative terminal, check voltage after a charge, then check again in the morning. If the battery holds steady at whatever you get (12.0, 12.5, 12.8, etc...) then you can be sure it's not the battery.
Keep in mind that "12 volts" means your battery is over half dead.
Hopefully, it's cheap & easy, and some clean terminals on a new battery will be all you need.
ivnic8
> BJohnson11
09/16/2013 at 16:06 |
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You might consider removing unnecessary light bulbs: glove box, under the hood, etc. I recently purchased a vehicle that had a loose glove box latch that would leave the light on - this would drain the battery, and it would also cause the Check Engine light to come on.