Automotive

Car Batteries - FAQ, General Information, Tips & Tricks

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  • Dec 8th, 2018 9:15 pm
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craftsman wrote:
Feb 12th, 2018 1:41 pm
Battery performance will depend on the temperature of the battery. In theory, CCA is supposed to compensate for that but realistically, I've found that testing CCA in cold weather will drop the CCA performance in regards to warmer weather (usually about 10 to 15%). The other issue is if you recently charged or ran the car within the last few hours. If you did, the battery has a surface charge of some degree which will need to be dissipated before a reliable test can be done.

Questions -
* Are you seeing any issues in starting your car?
* How old is the battery?
3yr old Kirkland battery, but I have dashcam in park mode. Could that be ageing the battery sooner?

When cranking, the RPM seemed to choke a bit, starts low and crawl back up, or need recrank once in a while. Also light dims when cranking. But it cranks, never got stranded unless I overdraw.
Last edited by LongLiveRFD on Feb 12th, 2018 3:29 pm, edited 1 time in total.
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macnut wrote:
Feb 12th, 2018 2:49 pm
Battery testing is not an exact science - as evidenced by your contrasting results minutes apart.

That is the sort of tester Walmart uses, though their's is probably better quality.
Assuming yours is broadly accurate, the fact that you only got 22% SOH on the 2nd. run suggests to me that your battery is on borrowed time.
SOC will of course vary quite a bit depending on when you test it, but SOH should be relatively constant.
So if battery bad, both battery test and cranking test would be iffy, correct?

Battery Test Both Run:
1st run: SOH=67%, SOC=0%, 12.00V, 355A/795CCA, R=9.22mOhm, Good-Recharge
2nd run:SOH=22%, SOC=73%,12.44V, 405A/795CCA, R=7.96mOhm, Replace

What should I do from now, as it cranks ok.

Keep testing and expect results to settle? test when car cool down or when still hot?
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LongLiveRFD wrote:
Feb 12th, 2018 3:29 pm
3yr old Kirkland battery, but I have dashcam in park mode. Could that be ageing the battery sooner?

When cranking, the RPM seemed to choke a bit, starts low and crawl back up, or need recrank once in a while. Also light dims when cranking. But it cranks, never got stranded unless I overdraw.
There are issues with your battery's current state as verified by your observations and tester. I think you already knew even before you got the tester.

Here's what I would suggest that you:
1. Service the battery terminals! It's been 3 years since it was installed and things happen in those 3 years! Remove and clean off the terminals. Battery terminals take a lot of abuse due to the environment that they live in and often, things work their way loose so make sure they are tight and while you are there, make use that they are clean. Put some dielectric grease (just a thin coat) on terminals once clean and re-attach to the battery.
2. Check the battery's fluid level. If low add distilled water until the plates are covered. Don't over fill as the battery electrolyte level will rise when charging and you don't want any acid coming out.
3. Charge the battery. At 73% state of charge, that battery is nowhere close to full and is the typical condition a 'car charged' battery is as most cars will only charge a battery to about 80% at the best of times. Get an outboard charger.

A dashcam that is always on won't do much harm AS LONG AS you don't leave the car parked for days or weeks as the battery will be drawn down constantly without a chance of charging.
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LongLiveRFD wrote:
Feb 12th, 2018 3:37 pm
So if battery bad, both battery test and cranking test would be iffy, correct?

Battery Test Both Run:
1st run: SOH=67%, SOC=0%, 12.00V, 355A/795CCA, R=9.22mOhm, Good-Recharge
2nd run:SOH=22%, SOC=73%,12.44V, 405A/795CCA, R=7.96mOhm, Replace

What should I do from now, as it cranks ok.

Keep testing and expect results to settle? test when car cool down or when still hot?
How are you testing the battery? Yes, I know with the tester but are you connecting it right to the terminals? After you have just driven the car? Overnight?

The reason why I'm asking is that those results should NOT change from one minute to the next. Seeing the wide variation in results from one run to the next is telling me that something is wrong. So, I follow the three steps I outlined above first and then test the battery again.
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Along with the suggestions Craftsman provided, I would do the following:

disconnect battery from the car to remove any draws or variables.
plug in a charger to fully charge the battery
after charging, remove the charger and let the battery sit disconnect for about 30 to 60 minutes
run your test tool to measure battery voltage. Take a reading
run a test again and compare this reading to the previous. They should be relatively the same.


I have one of these inexpensive units and repeated testing only changes my CCA marginally as well as my voltage and state of charge: https://www.amazon.ca/eOUTIL-Digital-Ba ... cca+tester
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Forgot to say, I did first run when engine cold, second run after I drove somewhere nearby.

But distance is so short, SOC should not jump from 0% to 70%.
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hightech wrote:
Feb 13th, 2018 9:30 pm
LongLiveRFD,

A few more questions:

What is the make/model/year of the vehicle?
How many KM do you have on it?
Did you do a test to see what the alternator voltage is at?
07 Buick Allure CXL, 80K
Charging: Both runs normal, Loaded=14.04V, Unloaded=14.50V
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LongLiveRFD wrote:
Feb 13th, 2018 8:50 pm
Forgot to say, I did first run when engine cold, second run after I drove somewhere nearby.

But distance is so short, SOC should not jump from 0% to 70%.
What you are seeing is the surface charge and the two readings should not be used for comparison.

And having a SOC of 0% means that the battery for all purposes is dead as a door knob. Since you started the car, that's obviously not the case so something is wrong.
Last edited by craftsman on Feb 14th, 2018 12:41 am, edited 1 time in total.
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hightech wrote:
Feb 13th, 2018 7:30 pm
Along with the suggestions Craftsman provided, I would do the following:

disconnect battery from the car to remove any draws or variables.
plug in a charger to fully charge the battery
after charging, remove the charger and let the battery sit disconnect for about 30 to 60 minutes
run your test tool to measure battery voltage. Take a reading
run a test again and compare this reading to the previous. They should be relatively the same.


I have one of these inexpensive units and repeated testing only changes my CCA marginally as well as my voltage and state of charge: https://www.amazon.ca/eOUTIL-Digital-Ba ... cca+tester
For an accurate measurement of the condition of the battery, you dissipate the surface charge and 30 to 60 minutes won't do it... you need hours. Ideally, overnight. Or you could turn on your headlights with the engine off for about 5 minutes, turn the lights off and wait for 5 minutes before testing. The quick method is not as accurate as overnight but it will get you in the ballpark.
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In the market looking to buy a Battery Booster Pack, anyone got any good suggestions.
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Is there reference here that can determine the proper car battery one should purchase?

I drive a 2013 Subaru Impreza, 2.0L
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speedyforme wrote:
Feb 22nd, 2018 9:14 am
Is there reference here that can determine the proper car battery one should purchase?

I drive a 2013 Subaru Impreza, 2.0L
The proper on is one that fits the car and the measure of that is generally the group number for the battery. In your case, you are looking for a Group 35 battery regardless of brand and type.

Is there an issue you are trying to address?
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craftsman wrote:
Feb 22nd, 2018 1:39 pm
The proper on is one that fits the car and the measure of that is generally the group number for the battery. In your case, you are looking for a Group 35 battery regardless of brand and type.

Is there an issue you are trying to address?
Thank you. No but I am pretty certain my battery needs to be replaced as it is weaker and has not been replaced once since 2013.
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speedyforme wrote:
Feb 22nd, 2018 1:43 pm
Thank you. No but I am pretty certain my battery needs to be replaced as it is weaker and has not been replaced once since 2013.
Time is not necessarily an indication of battery health; although, many people mistakenly do think that way. You should service your battery first, then charge your battery with an outboard charger, and then get it tested before replacement.

Since it's the factory battery, it's a Panasonic battery which requires maintenance especially after 5 years - have you checked the connections and topped off the cells (you can remove those 6 caps on the top but unscrewing them)? Chances are your fluid levels are low.

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