Automotive

Car Batteries - FAQ, General Information, Tips & Tricks

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  • Mar 22nd, 2024 2:24 pm
Sr. Member
Jan 24, 2009
538 posts
166 upvotes
Regina
Should check state of charge before adding water to the cells. A discharged battery will appear to have a lower level of electrolyte. If you top up a discharged battery and charge, you can potentially have it leak out.
Deal Expert
Jan 27, 2006
21844 posts
15620 upvotes
Vancouver, BC
nmiller8787 wrote: Should check state of charge before adding water to the cells. A discharged battery will appear to have a lower level of electrolyte. If you top up a discharged battery and charge, you can potentially have it leak out.
You could but realistically if you just add enough distilled water so that the plates are covered, you'll be fine. I believe the reason why people always suggest charging the battery first is that some old fast chargers (ie those that charge at 20A or 40A) may cause the battery to start to off-gas causing large air bubbles to form between the plates and dislodging the fluid and thus raising the level of electrolyte. Most home chargers won't even get to 10A...
Sr. Member
Jan 24, 2009
538 posts
166 upvotes
Regina
craftsman wrote: You could but realistically if you just add enough distilled water so that the plates are covered, you'll be fine. I believe the reason why people always suggest charging the battery first is that some old fast chargers (ie those that charge at 20A or 40A) may cause the battery to start to off-gas causing large air bubbles to form between the plates and dislodging the fluid and thus raising the level of electrolyte. Most home chargers won't even get to 10A...
You’re correct with home chargers being too weak to cause electrolytes to leak out. I did it a few times in my early days of working in the battery industry and it was always with a high amp charge.
Deal Addict
Nov 21, 2014
3580 posts
6290 upvotes
Atlantic
Just wanted to share my recent battery story.

Have a with 4.5 year old stock Panasonic battery (390 CCA, quite low to start with). Noticed more recently in these winter months it took a lot more cranks to get the car started.

Ended up getting a charger and a battery tester. Charged the battery overnight and then used the battery tester the following day.

Under the load test, the battery tester showed CCAs in the 250s. Not horrible but not that great either. Ran the test a few times, roughly the same CCAs, battery health was 35% on first test (battery tester actually said to replace battery that time) and then 40% on subsequent tests (battery tester said "good battery" on subsequent tests).

Fast forward to today when it was -7 degrees. I tried the load test again - 225 CCAs. Battery tester says to replace. I also realized that there was a cranking test. This is where the battery failed big time, voltage dropped to 6.9V while cranking.

Looks like a new battery is in store this weekend. Thinking of upsizing to a larger battery. Stock is a 35, but looks like there's adequate room for a 34.
Deal Expert
Jan 27, 2006
21844 posts
15620 upvotes
Vancouver, BC
EasyCompany251 wrote: Just wanted to share my recent battery story.

Have a with 4.5 year old stock Panasonic battery (390 CCA, quite low to start with). Noticed more recently in these winter months it took a lot more cranks to get the car started.

Ended up getting a charger and a battery tester. Charged the battery overnight and then used the battery tester the following day.

Under the load test, the battery tester showed CCAs in the 250s. Not horrible but not that great either. Ran the test a few times, roughly the same CCAs, battery health was 35% on first test (battery tester actually said to replace battery that time) and then 40% on subsequent tests (battery tester said "good battery" on subsequent tests).

Fast forward to today when it was -7 degrees. I tried the load test again - 225 CCAs. Battery tester says to replace. I also realized that there was a cranking test. This is where the battery failed big time, voltage dropped to 6.9V while cranking.

Looks like a new battery is in store this weekend. Thinking of upsizing to a larger battery. Stock is a 35, but looks like there's adequate room for a 34.
Remember that those numbers are relative to cold - ie the colder the weather the lower the CCAs are reported by standard testers and most testers won't do any adjustments for temperature. As the weather warms back up, the CCAs will also go back up.

Also, the measurements recorded only have a loose relationship with the ability to start any particular car - ie car A might crank fine with 250 CCA while car B won't crank at all - so take those general readings of GOOD Battery and replace with a grain of salt relative to current temperatures AND past history of how well your car starts with a particular amount of CCA.

As for upsizing it, I wouldn't for the following: The factory battery (since it's a Panasonic battery, I'm assuming it an OE battery) is only rated for 390 CCA (is it a Subaru by any chance?). Even the lowest priced 3rd party after market Group 35 battery is rated for 500 CCA and up so you are basically increasing the starting capacity by at least 25% over the OE one when new and double what will crank your car now (ie 250CCA x 2 = 500CCA).... If you get a Kirkland one, they are rated for 640 CCA (and will probably measure higher than rated when new) which is 50+% more CCA than OE. Upsizing may buy you a bit more reserve capacity than a standard Group 35 however.

One thing of note when changing batteries - DON'T throw out that plastic battery liner cover the sides of the battery as supplied by the OEM. That's there to insulate the battery from the heat of the engine. Removing that liner will reduce the overall lifespan of the battery as the heat from the engine WILL cause the water in the electrolyte to evaporate in the cells closest to the engine resulting in possible stratification of the electrolyte and excessive sulphation. A bit earlier, I posted about my brother's car battery and how a load tester was used to recover some of the cranking capacity. The previous owner of that car removed that liner from the battery and I found, upon inspection, that the cell closest to the engine was actually heavily sulphated - ie you can see the sulphate crystals covering all of the plates as if someone poured a pile of salt into the battery's cell. All of the other cells looked fine. I was luckily enough to find it in time before the battery completely failed and was able to address the issue.
Deal Expert
Jan 27, 2006
21844 posts
15620 upvotes
Vancouver, BC
EasyCompany251 wrote: Yup an Impreza.
I have a 2013 Crosstrek with a battery in a similar condition (almost exactly the same numbers by the way). While I still have the OE Pansonic battery, I recently purchased an used Kirkland battery that was 6 months old when I got it. I basically refurb'd the Kirkland and used it during the cold spell here in Vancouver. While the Kirkland was in the Crosstrek, I tried a few things with the OE Panasonic battery and was basically able to improve the battery's condition somewhat. The battery would drain a bit even after charging (read 12.42 V the day after charging and go down into the 12.2Vs after a few more days). After doing a few hard discharges of the battery by starting it 4 or 5 times in a row and then recharging it with an equalization charge as well, I was able to fix the drain issue - the battery now will read 12.5+V the day after charging and hold that voltage for a week before dropping a bit.
Deal Expert
User avatar
Dec 23, 2003
18021 posts
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Toronto
Walmart sells an Everstart Maxx Group 35 with 640 CCA. Canadian Tire also sells a few Group 35 models. The one with the 4-year warranty is the one with more CCA.

Most batteries these days are from East Penn. You can find out the battery options for your vehicle here: http://dekacatalog.com/

Going from a 350 CCA to a 640CCA is a big improvement. You don't need to look at the Group 34 as it may be overkill for your needs. Just make sure you get a FRESH battery (should have 1/20, 2/20, A20, or B20 stickers for Jan or Feb 2020.)
Deal Addict
Nov 21, 2014
3580 posts
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Atlantic
Yeah so I ended up getting an OEPlus from Canadian Tire. Group Size 35, 650 CCA. 4 year warranty.
Deal Expert
Jan 27, 2006
21844 posts
15620 upvotes
Vancouver, BC
hightech wrote: Walmart sells an Everstart Maxx Group 35 with 640 CCA. Canadian Tire also sells a few Group 35 models. The one with the 4-year warranty is the one with more CCA.

Most batteries these days are from East Penn. You can find out the battery options for your vehicle here: http://dekacatalog.com/

Going from a 350 CCA to a 640CCA is a big improvement. You don't need to look at the Group 34 as it may be overkill for your needs. Just make sure you get a FRESH battery (should have 1/20, 2/20, A20, or B20 stickers for Jan or Feb 2020.)
I would say that since @EasyCompany251 has a battery tester, they don't necessarily need to find the FRESHEST battery as the tester can test for the relative markings of 'FRESH' - ie Internal Resistance, CCA, and voltage. Now, if there wasn't a tester available, then absolutely go for the FRESHEST battery as the battery is literally a black box otherwise!

As to what to look for in regards to internal resistance, CCA, and voltage, voltage is probably the easiest as you want a battery that is FULL in relation to the state of charge so anything above 12.7V for a new battery. The higher that voltage is, the newer the battery assuming no-one has come around to top off the charge (the self discharge rate for a lead acid battery may range from 4% a week to 5% a month depending on the source of information so the closer it is to the initial charge, the higher the voltage should be). The next two, CCA and Internal Resistance, are basically interconnected - the lower the internal resistance, the higher the CCA. For example, a 640 CCA battery will have an IR reading of approx 4.3 mOhm or so while a 300 CCA battery will be about 9 mOhm. Since the batteries have the rated CCA written right on the battery itself, look for one that will test ABOVE the rated number - ie if it's rated for 600 CCA, the tester should read above 600 CCA for a fresh battery. If the readings are off (ie CCA lower than rated but the voltage shows that the battery is full), pass on that battery regardless of how fresh it is.
Deal Expert
Jan 27, 2006
21844 posts
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Vancouver, BC
EasyCompany251 wrote: Yeah so I ended up getting an OEPlus from Canadian Tire. Group Size 35, 650 CCA. 4 year warranty.
I would do two things with a new battery -> Fully charge that battery and then test it after sitting overnight fully charged. By fully charging the battery, you basically make the battery as fresh as it can be as the sulfates that may have built up while it's been sitting on the shelf (as long as its recent sulfate) will be dissolved. Testing the day after will verify that you got a good battery in the first place and gives you the numbers of what a new battery should look like.
Deal Addict
Nov 21, 2014
3580 posts
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Atlantic
I tested the new battery before installing into the car.

Voltage was 12.8x, so fully charged already.

The CCA also tested @ 795. Spec says 650.

Crank test voltage drop to 9.4V. Edit: Might seem a bit low....but I think it might have to do with temperatures as well. Roughly -7. Guess we'll monitor moving forward.
Last edited by EasyCompany251 on Feb 9th, 2020 11:12 am, edited 2 times in total.
Deal Expert
User avatar
Dec 23, 2003
18021 posts
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Toronto
EasyCompany251 wrote: I tested the new battery before installing into the car.

Voltage was 12.8x, so fully charged already.

The CCA also tested @ 795. Spec says 650.

Crank test voltage drop to 9.4V
Crank voltage to 9.4 volts on a NEW battery? that does not sound right. I know they mention 9.6 volts as a base number and most new batteries crank voltage should never be below 10.3 volts.

Do you have a volt meter? If so, plug it in and then try to start the battery. What make/model of battery tester do you have?
Jr. Member
Sep 25, 2017
165 posts
157 upvotes
GTA
EasyCompany251 wrote: Just wanted to share my recent battery story.

Have a with 4.5 year old stock Panasonic battery (390 CCA, quite low to start with). Noticed more recently in these winter months it took a lot more cranks to get the car started.

Ended up getting a charger and a battery tester. Charged the battery overnight and then used the battery tester the following day.

Under the load test, the battery tester showed CCAs in the 250s. Not horrible but not that great either. Ran the test a few times, roughly the same CCAs, battery health was 35% on first test (battery tester actually said to replace battery that time) and then 40% on subsequent tests (battery tester said "good battery" on subsequent tests).

Fast forward to today when it was -7 degrees. I tried the load test again - 225 CCAs. Battery tester says to replace. I also realized that there was a cranking test. This is where the battery failed big time, voltage dropped to 6.9V while cranking.

Looks like a new battery is in store this weekend. Thinking of upsizing to a larger battery. Stock is a 35, but looks like there's adequate room for a 34.


Subaru OEM battery is not suitable for winter condition. Mine just died less than 2 years from new, I got it replaced under warranty and now it is working fine and strong. No longer the liquid one, they replaced with a solid AGM one by Subaru but smaller.

... I know it's a Subaru because 390 CCA.. too weak under cold condition.
Deal Expert
Jan 27, 2006
21844 posts
15620 upvotes
Vancouver, BC
DJRMITO wrote: Subaru OEM battery is not suitable for winter condition. Mine just died less than 2 years from new, I got it replaced under warranty and now it is working fine and strong. No longer the liquid one, they replaced with a solid AGM one by Subaru but smaller.

... I know it's a Subaru because 390 CCA.. too weak under cold condition.
It's fine under cold conditions as the @EasyCompany251 demonstrated during the past 4.5 YEARS. And if you go by the folklore that had been in this forum before this FAQ thread started, most people would have said that 5 years is a really old battery and it should be replaced anyways. Since this OE Panasonic battery lasted 4.5 years and has yet to fail, it was working to most people's expectations.

As for your battery dying under 2 years, it just might be that you received a defective battery from the start, the dealer let the battery sit on the lot for a while never charged it or as shown in this thread, you might not drive the car enough or too many short trips which resulted in premature battery failure.... Just because the battery is 'new' doesn't mean that the battery was in an ideal/perfect condition when you received it.
Deal Addict
Nov 21, 2014
3580 posts
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Atlantic
Since you guys seem so interested in my results, here's some pics.

Today was -11.

My tester is this one from Amazon: TopDiag Battery Tester

Pictures below: CCA load test, Crank/Start Test, Charging Test (just realized I had my headlights on.....pretty sure you're supposed to test with no accessories on)
IMG_20200209_125755.jpg
IMG_20200209_125530.jpg
IMG_20200209_125356.jpg
IMG_20200209_125321.jpg
IMG_20200209_125025.jpg
Pictures of old battery and stats:
IMG_20200211_190856.jpg
IMG_20200211_190935.jpg
Last edited by EasyCompany251 on Feb 11th, 2020 9:40 pm, edited 1 time in total.
Jr. Member
Sep 25, 2017
165 posts
157 upvotes
GTA
craftsman wrote: It's fine under cold conditions as the @EasyCompany251 demonstrated during the past 4.5 YEARS. And if you go by the folklore that had been in this forum before this FAQ thread started, most people would have said that 5 years is a really old battery and it should be replaced anyways. Since this OE Panasonic battery lasted 4.5 years and has yet to fail, it was working to most people's expectations.

As for your battery dying under 2 years, it just might be that you received a defective battery from the start, the dealer let the battery sit on the lot for a while never charged it or as shown in this thread, you might not drive the car enough or too many short trips which resulted in premature battery failure.... Just because the battery is 'new' doesn't mean that the battery was in an ideal/perfect condition when you received it.
You are right, in the past I made too many short trip daily. Not enough to keep it charged up. Like 10min drive on highway one way. Car not even warm up by the time I get to destination.

I should have gone for EV but I don't have charger nearby any sites.
Deal Expert
Jan 27, 2006
21844 posts
15620 upvotes
Vancouver, BC
DJRMITO wrote: You are right, in the past I made too many short trip daily. Not enough to keep it charged up. Like 10min drive on highway one way. Car not even warm up by the time I get to destination.

I should have gone for EV but I don't have charger nearby any sites.
If that's how you are currently driving as well, you should charge your current battery with an external charger once in a while (ie once every 2 to 3 months) in order to get the most life out of the battery as your new battery will suffer the same fate (may last a year or two longer) as your OE battery.
Deal Addict
Nov 21, 2014
3580 posts
6290 upvotes
Atlantic
Speaking of short trips, that is almost all I do. Daily work commute roughly 3 km one way.

Once or twice a week, I will go on the highway for 15-20 mins one way.

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