Questions tagged [battery-testing]

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I shorted the alternator for a second with a multimeter set to measure current

I was debugging a battery. The resting voltage was 10.8, which means either the battery is bad or there is something draining it. So to check the drain I had my multimeter connected to measure ...
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0 answers
42 views

What is the difference between a top and side post battery?

I'm looking in to getting a battery analyzer and whilst looking through the manuals, I came across an entry where you have to tell it whether the battery is side or top posts. What difference does ...
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1 answer
49 views

Left car battery "tipped" for a few months--is it safe to use?

A few months ago, I bought a new car battery and stored it sideways (silly me!) There's been a fair amount of leakage, which I've cleaned up. Is the car battery safe to use in a car? Is there some way ...
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0 votes
2 answers
288 views

Lithium car battery won't jump van's battery but regular jumper cables work

Twice over the past year my wife has left something on in our Honda Odyssey. Both times I've not been able to jump start the van using a NOCO 1000Amp 12-Volt lithium battery. But, both times I've been ...
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1 vote
1 answer
199 views

AGM Battery - Residual Voltage?

Wife's 2018 Mercedes GLA250. Car is 3 Years and 4 months old. Just turned over 12k miles. The AGM battery is at 12.25Volts after sitting unused for a week. Everything I read says an AGM battery should ...
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1 vote
2 answers
50 views

basics of charging a Lead Acid battery?

I want to build a poor man's portable power station. There are only two things I need to run off of it: a 240watt fan to blow up my mattress and a CPAP machine all night that is rated at 12v 3 amp. I ...
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1 vote
2 answers
2k views

Brand new lead acid car battery reads only 12.33v. Is it faulty?

Yesterday I purchased a brand new, maintenance-free, 12 volt lead acid car battery. Specs: 47Ah and 450CCA. Before I install it in my car, I measured the voltage with a catIII digital multimeter. It ...
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2 votes
1 answer
95 views

Alternator health check

My car (Fiat Grande Punto MY2008) has been having an occassional battery light and failure of the power steering. Perhaps once in every 10-15 startups, and is resolved by restarting the car. The car ...
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  • 215
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2 answers
4k views

Car battery at 11.8v in the morning and 12.5v after 20 minute drive bad?

If my group 48/H6 70AH 120RC Led Acid car battery is at 11.8v in the morning and 12.5v after a 20 minute drive is it bad? My van and battery are only 10 months old but I do frequently use the battery ...
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  • 161
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2 answers
39 views

Flat Battery, heath is down but charge is fine

yesterday, suddenly my car battery got flat, i was driving since one hour, i just stop on a shop and it didnt start again, i called the breakdown AA, they came and started my car, he said that the ...
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-1 votes
1 answer
92 views

Is there a way to reliably test voltage of a 12V battery when it's not disconnected (i.e., partly loaded)?

I'm having an issue where a fully charged battery doesn't necessarily report the proper voltage when checked from the socket within the car, because in order to have the socket activated, the car has ...
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5 votes
1 answer
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What is surface charge and how does it affect battery testing?

I've read in numerous places that "surface charge" can give false positives when testing a battery, and you need to remove the said surface charge to get an accurate result. I've also read various ...
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4 votes
0 answers
154 views

Can a Battery Conductance Test tell the difference between damaged plates and sulfation?

I'm just going to lay out my assumptions, or what I think I know, so that there's a better context for the question. I understand that there are basically four main situations in which a standard ...
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