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Questions tagged [battery-testing]

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Can I estimate the health of an old lead-acid battery by its rest open-circuit voltage at full charge?

Cars today use lead-acid batteries for the starting/lighting/ignition system. Hybrid vehicles that start the engine by a high-voltage battery do the same except for starting. Similarly, many electric ...
juhist's user avatar
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3 votes
2 answers
95 views

Battery Voltage drop

I want to install a new stereo for my car which requires 12V. I tested the battery first it and shows 12.29V but when I started the car the battery became 6V. Is this normal? What am i doing wrong?
walter's user avatar
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2 votes
1 answer
207 views

very old battery but healthy - replace?

the battery in my vehicle was manufactured in the 41st week of 2017. I've never had any issues with it. In my online research, many sources say batteries last from 3-5 years, which would make my ...
machump's user avatar
  • 123
1 vote
2 answers
459 views

Understanding the battery report on my vehicle

Had two questions about a battery report I received on my vehicle. The technician suggested I drive my vehicle more. I was hoping to understand why the report made him think that. The battery is ...
pmagunia's user avatar
  • 173
-1 votes
2 answers
124 views

Battery level indicators in dashboard of four wheeler vehicles

Dashboard Symbols Lead acid batteries v/s Lithium ion batteries Lithium ion batteries used in electric vehicles Are there Battery level indicators on the dashboard of four wheeler vehicles? Can ...
Prashant Akerkar's user avatar
3 votes
3 answers
5k views

New AGM 12V battery at 10.8V - charger says it is full

Yesterday I bought a new Varta Powersports 508 012 008 AGM 12V battery. Assuming it was mostly charged I immediately hooked it up to my generators starter motor and it started it without problem. ...
Yanick Salzmann's user avatar
4 votes
4 answers
2k views

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 ...
David's user avatar
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0 votes
0 answers
503 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 ...
cosmarchy's user avatar
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0 votes
1 answer
89 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 ...
user257566's user avatar
0 votes
3 answers
2k 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
887 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 ...
KIWIPOP's user avatar
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1 vote
2 answers
107 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 ...
Sam Carleton's user avatar
1 vote
3 answers
7k 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 ...
TheBlackRazorGT's user avatar
2 votes
1 answer
179 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 ...
james246's user avatar
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1 vote
2 answers
7k 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 ...
Hell.Bent's user avatar
  • 161
0 votes
2 answers
52 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 ...
Sajid Mehmood's user avatar
-1 votes
1 answer
109 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 ...
cnst's user avatar
  • 1,515
6 votes
1 answer
32k views

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 ...
Robert S. Barnes's user avatar
4 votes
0 answers
177 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 ...
Robert S. Barnes's user avatar