Motor Vehicle Maintenance & Repair Stack Exchange
Motor Vehicle Maintenance & Repair Stack Exchange

Questions tagged [battery-testing]

23 questions
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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 recommendations for removing surface charge such as…
Robert S. Barnes
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Can a low battery cause airbag and brake system check lights to light up?

I have a 2010 Honda Insight. I think the battery is low because the car doesn't turn over when I turn the key. I also used a multimeter and found the battery is 10.6V. The car is also giving me warnings regarding: Check Brake System Check Airbag…
Classified
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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 current. There was no drain, so I assume it's the…
David
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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 lead acid car battery will not be able to hold a…
Robert S. Barnes
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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
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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. After using it for a couple of seconds in total…
Yanick Salzmann
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Why is there a difference between battery post voltage and battery terminal voltage?

Hope I’m using the correct terminology here. I believe the posts on the battery are the positive and negative posts to which the cars positive and negative terminals are to be connected. I’m currently investigating some battery/battery drain…
James Wilson
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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 battery archaic. When I tested it with a multimeter,…
machump
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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 starts fine, but I am concerned the alternator…
james246
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How accurate is a battery test?

My daughter's car recently failed to start, empty battery. Daddy's jump leads helped. But just a few days earlier she had driven several hundred kilometers so the battery should have been fully charged. I advised her to get the battery checked,…
NL_Derek
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Battery on my 2022 ford bronco sport

I was just wondering if a battery can go bad due to other problems in the car for instance the purge valve going bad the turbo charger going out or a catalytic converter could any of these be a reason why a battery would go bad or what is dtc code…
Jessica LaChappelle
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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 vehicles have a 12-volt lead-acid battery that's…
juhist
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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 rated 450, and there were 762 cold cranking…
pmagunia
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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 have a residual voltage of 12.8v ~ 13.2v. Car…
KIWIPOP
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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 am pretty sure a mid-size 12v lead acid battery…
Sam Carleton
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