Battery question at low temps. (1 Viewer)

[JCruse]

When the outside temps drop to around freezing or below the resting voltage on my car batteries drops quite a bit from it's normal 12.8v or more, landing around 12.62 and staying there until it gets warmer. Now if I recall correctly this is normal (?) but when I went searching for a chart or something I found nothing. So if someone could school me on this I'd be much obliged. Thanks.

 

[george_tlc]

google foo power ->

http://www.crypton.co.za/Tto know/Basics/Batteries/State of Charge.pdf


cheers,
george.

 

[JCruse]

google foo power ->

http://www.crypton.co.za/Tto know/Basics/Batteries/State of Charge.pdf


cheers,
george.

I don't know about this. It says at 20 degrees subtract 0.144v. That would make my charged battery 12.65v (12.80 - .144 = 12.656) but I'm getting 12.35v after a very cold night or two. Admittedly the battery is connected but only to the HU and amp, everything else is disconnected this time of year.

It's a sweltering 33 today so I've got it back on the charger.

 

[george_tlc]

Do not assume that 12.80V is your standing 100% fully charged battery voltage. You need to find out what the manufacturer states the 100% state of charge voltage is for the particular battery model you have at nominal 80F. This is voltage with NO load.

cheers,
george.

 

[JCruse]

Lifeline says 13V for this house battery. But that's disconnected.

I always new that batterys give less juice in the cold (duh) but I didn't know that they just didn't have anything to give. They actually lose the voltage somewhere. I charge it to 13.2 say, and that night it's down to 12.3 if it's in the 20's or teens. Where'd it go? ?

 

[george_tlc]

Battery voltage is a chemical reaction. The voltage didn't go 'anywhere', it is what the chemical reaction provides at that temperature...

cheers,
george.

 

[half k cruiser]

Are you having a starting issue ? More so then what's to be expected given the temperature in your area ?

 

[JCruse]

Battery voltage is a chemical reaction. The voltage didn't go 'anywhere', it is what the chemical reaction provides at that temperature...

cheers,
george.

That's about as good an explanation as any on this subject, thanks.

So what about sulfation then? Normally a 12.2V battery would be growing crystals at that level of discharge. Given a whole winter to do this I would think a lot of damage gets done this way. But I guess maybe crystals form more slowly in the frigid cold..?

No Half-K Cruiser, no real issues with starting. Just slower cranking. My main concern is sulfation, and I'd like to know a bit more about how best to deal with this for battery longevity.

 

[Hiace4wd]

You could measure the CCA with one of those meters that a garage usually has, and then measure difference at freezing temperatures and on warmer days (when it cranks better)