Car batteries freeze??

Status
Not open for further replies.
Joined
Dec 4, 2004
Messages
2,183
Location
Lexington, KY
Anyone heard of a car battery freezing? My daughter lives in Wasausa(sp), WI and the temp was about -19 and with a wind chill of about -40 or so and one of her friends had a battery freeze and crack. How does this happen and what should be done to prevent it?
 
Last edited:
Considering the freezing points of sulfuric acid (283 Kelvin) and water (273 Kelvin), I would expect that the ions are the only things keeping the battery from freezing. I cannot say for certain, but it is possible that lead acid batteries could freeze when the temperature drops to 254 Kelvin.

A possible solution could be to use a different battery chemistry. Lithium Ion batteries freeze at 233 Kelvin, but they lose their capacity as a function of time and the ambient temperature. Given how hot it can be in the hood of a car, Lithium Ion batteries are probably not a good choice. There are other chemistries that are avaliable, which you can read about on wikipedia.

Another possible solution would be to insulate the battery, although a potential problem with that would be that the maximum temperature that it would encounter during the summer would be increased, so partially insulating it might be preferable.
 
Yep, discharged batteries will freeze. A friend of mine left something on in his truck at the park-and-fly last week and needed two new batteries for his truck when he got back.
 
Keep the battery charged. If it's not possible to drive the car on a regular basis or to connect an AC powered charger, you can get a solar charger from Harbor Freight:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=44768

This will do a fine job of keeping the battery charged.

This is assuming that something wasn't left on to cause the battery to discharge. The above solar charger will compensate for the vehicle's parasitic draw and for the battery's self discharge. It can't compensate, for example, if someone leaves a cellphone charger plugged in.

At 100% charge, a battery will freeze at -77F. At 75%, -35F. At 50%, 10F. At 25%, 5F. At 0% (totally discharged), 20F.
 
Last edited:
Originally Posted By: ShiningArcanine

Another possible solution would be to insulate the battery, although a potential problem with that would be that the maximum temperature that it would encounter during the summer would be increased, so partially insulating it might be preferable.


As a matter of fact, many manufacturers install battery insulators to protect them from engine heat. It's not going to do anything to keep a battery from freezing though--the battery which is sitting idle isn't producing any heat at all. Which is why the wind chill doesn't matter here.
 
Originally Posted By: ShiningArcanine
Considering the freezing points of sulfuric acid (283 Kelvin) and water (273 Kelvin), I would expect that the ions are the only things keeping the battery from freezing. I cannot say for certain, but it is possible that lead acid batteries could freeze when the temperature drops to 254 Kelvin.


For those of us who don't think in Kelvin, those temps are:

283 kelvin = 49.73 degrees Fahrenheit

273 kelvin = 31.73 degrees Fahrenheit

254 kelvin = -2.47 degrees Fahrenheit

How did you determine that 254 K was the potential freezing point?
 
Originally Posted By: brianl703
It's not going to do anything to keep a battery from freezing though--the battery which is sitting idle isn't producing any heat at all. Which is why the wind chill doesn't matter here.


In a marginal case, it can. Insulation slows the flow of heat both ways, so it depends on the R value of the insulation, the time and temperature. If the car is sitting for a month, it won't make a difference. But it might be enough to prevent freezing overnight.
 
Yea, but if the charge on that battery is dropping overnight to the point where freezing is a problem, there are problems that a battery insulator still isn't going to help--either a faulty battery or a parasitic load or a faulty alternator.
 
Last edited:
brianl703 - I knew that a discharged battery could freeze, but I am curious about where you got the data of the %charge vs FP?
 
Originally Posted By: swalve
Originally Posted By: ShiningArcanine
Considering the freezing points of sulfuric acid (283 Kelvin) and water (273 Kelvin), I would expect that the ions are the only things keeping the battery from freezing. I cannot say for certain, but it is possible that lead acid batteries could freeze when the temperature drops to 254 Kelvin.


For those of us who don't think in Kelvin, those temps are:

283 kelvin = 49.73 degrees Fahrenheit

273 kelvin = 31.73 degrees Fahrenheit

254 kelvin = -2.47 degrees Fahrenheit

How did you determine that 254 K was the potential freezing point?


The original poster said that the ambient temperature was 19 degrees below zero when the battery had broken, although in hindsight, it would have been better to say 250 kelvin to take into account significant figures.
 
Thanks Brian. That is an interesting web site! If you go to the home portion (jgdarden.com) it is a photographer's site. Confusing to me (the site), but very interesting. Lots of info on batteries.
 
Years ago, I was a mechanic at a big boat yard. In the winter, we removed the batteries from all the boats and placed them on shelves in a well ventilated shed all paralled to a few automatic chargers. My boss told me that as long as we kept them charged, they would not freeze. I guess he was right because for two years I worked there, we never lost a battery.
 
When it's discharged ..it's mostly water ..as everyone sorta said. That's why you typically can't recover a battery that's been idle for too long in a freezing environment, even if it was new when idled. The freezing, even if it doesn't break the case, screws up the plates and connections.
 
Originally Posted By: swalve
Originally Posted By: ShiningArcanine
Considering the freezing points of sulfuric acid (283 Kelvin) and water (273 Kelvin), I would expect that the ions are the only things keeping the battery from freezing. I cannot say for certain, but it is possible that lead acid batteries could freeze when the temperature drops to 254 Kelvin.


For those of us who don't think in Kelvin, those temps are:

283 kelvin = 49.73 degrees Fahrenheit

273 kelvin = 31.73 degrees Fahrenheit

254 kelvin = -2.47 degrees Fahrenheit

How did you determine that 254 K was the potential freezing point?


I did not determine that 254 K was the potential freezing point. The original poster reported that the battery cracked at 19 degrees below 0.
 
Status
Not open for further replies.
Back
Top