Battery Tenders; Winter Storage
 

Hello all!

I'll start by saying that I've lived in MN my whole life and have stored cars in the past without any major issues. This year I am looking to get a battery tender for a couple cars, one being my recently purchased 370Z. Rather than pull the batteries and lug them inside I'd like to use a dual tender. I've never used one of these before and would like to know if the amps provided are enough to keep the cells from freezing. I had a brand new battery freeze and blow out on me last year and I'm not looking to have that happen again as they don't warranty batteries if they freeze unfortunately (not to mention the mess of acid all over the floor in the spring).

Any other tips I should be aware of? Jackstands? Blocks? Leave car on the ground?

Location:
Central MN

Temps:
< -20 Degrees F at times.

Car in question:
2010 40th Anniversary
51k miles
6MT

Why would you live in Minnesota?

I've asked my parents that very question a multitude of times. :shakes head:

And no, I do not live with my parents. But I didn't choose to be born here, and after college, I went where the job was, and that was..... here.

As an Iowa Z owner, I will also be storing my Z for the winter. I was planning on getting this battery tender off of Amazon, and leaving it connected in my garage.

I'm also interested in some winter storage tips (I just bought the car back in April)!

Im in NJ, im drivin this bad mofo alllll winter.
There might be RIP thread for me, please, only post the good things about me.




P.S. Knock on wood.

Go with the Battery Tender Plus, not the JRs. I have used them for decades on bikes cars & trucks all with fantastic results, although I have never had the freezing issue you have. I would give them a call @ 877-456-7901 & express your concerns. They may recommend a different model or another solution.

HTH

that's the same one i used for my porsche. i recommend it. also, cut some 3/4" thick plywood into 4 pieces approx 1x2 feet and space them out and when you store your car park it so the wheels are on the boards, off the cold concrete. i also put a pan filled with charcoal under and even ibsaide the car to absorb the moisture, good luck.

They make dual battery tenders. Only issue I foresee would be whether or not the cords will be long enough to reach both batteries without removing them from the cars. If you are not wanting to bring the batteries inside, I'd recommend buying a battery warmer for each one as well to prevent freezing.

Search hibernate

Never would have thought of the charcoal idea. Brilliant!

..or just get a hygrometer and confirm there's not much RH to begin with in the winter...

too early to think about the 'W' word

And I used one last winter. Car fired right up in the Spring.

Heated or insulated garage? Mines going to be out in a cold non-insulated garage, concrete floor.

As far as freezing goes, it's the concentration of acid that matters (indirectly measured by battery charge; full charge = greatest concentration = lowest freezing point) not the amps that the charger/tender puts out. As long as the tender will keep the battery fully charged (shouldn't be a problem unless your battery is in bad condition), chances of freezing will be minimized. I don't recall what the freezing point of battery electrolyte is but I've seen -30F with no freezing problems (it cranked real slow, but didn't freeze). If you think your storage area will get below that, use a heater.

Edit: looked it up and a fully charged battery (SpG = 1.265) is good down to about -75F. At 75% charge (SpG = 1.22; 12.4V for conventional Pb-acid battery, 12.8 for maint-free), you can get down to -35F before freezing.

Neither. Non-heated but insulated garage, concrete floor.

I think a battery exploding is really rare, and moreso a result of a defective battery than the cold. I've had my DD sit out in -20+ temps for a couple weeks with no issues.