12 volts battery issue

C

C-Wolfe

Member
I have issue with a car battery, so I hope this is ok to ask here since I know there is some very knowledgeable folks on this site. At the end I would most likely replace the battery but I'm just curious about what might be happening. It is also very cold (below 0 F) and we just got over 4 ft of snow in the last week or so, which make it even more appealing to try to solve my problems with a computer :D

The car (Subaru 2013) had been sitting for about 48 hours since its last use, temperatures have been in the single digit above and below 0, we've been getting lots of snow recently, battery is 3 years old and never had any issues. My wife went to use the car and nothing worked, when I got home I tested the battery and it showed about 0.1V, I took the battery inside, cleaned the top and opened the vent, all cells are full and not frozen. I rechecked the battery, 5V now. I plugged it to my smart charger and it first showed a faulty battery but that went away and it is now fully charged. I will be putting it back in the car soon to see what happens and do more testing.

I never had a battery go to 0, I'm very curious as to what happened and if I should trust this battery even if it do fine today.
 
You should check the car for an unexpected load on the battery. Before you reinstall the battery use an ohm meter to check the impedance from the positive lead to chassis. For the battery to completely discharge in 48 hours you would need an impedance of less than 10 ohms.
 
Dealing with batteries in the cold on a ranch in Alberta is just part of winter for me. A three year old battery should not in itself be the problem unless it is faulty. Most batteries I buy are supposed to last 8 to 10 years, but rarely do in cold weather, 5 or 6 years is more likely. My feeling is that there must be something that is drawing down your battery in the car. In the summer this might be so low that it is not a problem, but in the winter when the normal capacity of a battery is perhaps 50% it becomes a problem. I would fully charge the battery indoors and load test it, a battery shop can do this for you. That is your starting point. If the battery fails this test then I would replace it, especially in winter. I would also start looking for anything that might drain your battery and this can be very difficult. In really cold weather I make a habit of turning off all electrical switches I can, including the radio and fan when I park my truck or tractor. I have had the dome light drain my battery in my tractor overnight because I left it on. The same thing has happened in a truck when I did't close a door properly. In one case I had a bare wire drain the battery on my tractor. This cost me over $3000 to fix, actually $2900 for the mechanic to find the bare wire and $100 to splice the wire. Good luck hope these help.
 
On my truck I had a similar problem but it was during spring. When I bought it, the battery would go flat in a day. I could jump the truck in the morning and it would work fine all day. But after parking overnight it would be dead the next morning. The battery was 1 year old when this happened. I had the battery tested at the auto parts store, they cycled it and load tested it and said it was fine. Put the battery back in the truck and it worked for one day and then was flat again. Replaced the battery and everything has been fine since (almost 4 years now).
 
Subaru has had a problem with battery drain in their cars. You can google info on it and there is a class action suit collecting names here - https://www.subarubatterysettlement.com/


Battery problems become more pronounced the colder the weather gets. Parasite drains are often very hard to pinpoint. Batteries can also have an internal short between plates that will drain them. This is one reason marine rated batteries should be used in a boat as opposed to auto - the plates are more robust as are the supports between them. This is also why I don't recommend using the 1,000 amp group 24 batteries in a boat - their plates are very thin and closely spaced.

I do like Subaru vehicles though and I would have had one by now if new ones were available - in the model I want.

Rob
 
Look like the battery is fine as far as I can tell for now. I didn't do a load test but...battery was fully charge by late morning and voltage look good-14.5 while charging and close to 13 after removing the charger. I did have about 4-5 ohm between + and - but as it turn out, the passenger seat electric switch was stuck in forward. So that's what must have killed the battery. It is an issue we had a couple year after we got the car but it went away for a long time, I guess it's back now and might have to fix this soon.

Thanks for all the help, I really appreciate it.
 
I have some radio gear in my truck and between the parasitic loads from that and other accessories, my battery would be unable to start the vehicle if I hadn't driven it for a week or so. Finally put one of these small solar panels on the dash to keep things topped up and have not had a problem since.
 
My son's subaru will drain the battery in a short time if the keys are left in the ignition and that is with the keys just inserted and not turning them at all.
 
If the battery stays charged out of the car then the problem is a drain from the car. It looks like you found the problem with the seat. Thankfully that is pretty easy to track down.
 
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