Winterizing

[Brownhouse]

Planning ahead, I know I can't charge Lifepo4 batteries below 32 degrees but for winter storage can I disconnect and leave them on board in freezing temps without doing damage?
They are in a tight space and it's a pain to get them out.

 

[upnorthandpersonal]

In principle, and from everything I've read (and done) it should be fine.
A source: https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/

Quote: "Storing batteries below freezing is fine, even at very low temperatures such as -40 Centigrade (that is the same in Fahrenheit), or even less! The electrolyte in LiFePO4 cells does not contain any water, so even when it freezes (which happens around -40 Centigrade, depending on the particular formulation) it does not expand, and does not damage the cells."

Also: " Storing them at low temperatures is certainly much better than storage at high temperatures: Calendar aging slows down dramatically at low temperatures. " --> so it might even be a good thing!

 

[Brownhouse]

In principle, and from everything I've read (and done) it should be fine.
A source: https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/

Quote: "Storing batteries below freezing is fine, even at very low temperatures such as -40 Centigrade (that is the same in Fahrenheit), or even less! The electrolyte in LiFePO4 cells does not contain any water, so even when it freezes (which happens around -40 Centigrade, depending on the particular formulation) it does not expand, and does not damage the cells."

Also: " Storing them at low temperatures is certainly much better than storage at high temperatures: Calendar aging slows down dramatically at low temperatures. " --> so it might even be a good thing!

Thanks, much appreciated

 

[Wibla]

Make sure you disconnect them from any loads. The best way to do this is to physically disconnect the battery from the rest of the system.

 

[jlangri]

My concern is more with charging them cold. I installed Gyll LifePO4's in my bassboat which is stored in an unheated garage. I recharge using an onboard Noco GEN3 30A 3 bank charger. Regardless of season, I usually recharge immediately upon returning from the lake, but in Winter the temperature during the drive home can drop drastically below freezing.

Getting closer to Fall and Winter, I'm beginning to get concerned. I've looked at battery heating pads and blankets, but the specs always state that they are not to be used for Lithium batteries. My initial plan is to use a thermostatically controlled power strip along with a 60w or 100w flood light in a clamp-on fixture in the battery compartment to hopefully warm it to somewhere around 60°~70° degrees before charging.

Am I overreacting?

 

[JoeHam]

Not overreacting.

Be certain to have the battery core temp above freezing before charging.

60-70 degrees is completely unnecessary.

 

[chrisski]

For those that have stored these batteries for long periods of time in the cold, have they discharged? The spec sheets I look at want batteries recharged every so often, which that interval is shorter than the winter,

 

[jlangri]

Not overreacting.

Be certain to have the battery core temp above freezing before charging.

60-70 degrees is completely unnecessary.

Thank you!

 

[Horsefly]

Getting closer to Fall and Winter, I'm beginning to get concerned. I've looked at battery heating pads and blankets, but the specs always state that they are not to be used for Lithium batteries.

This will come as shocking news to many of us that have built or are building insulated, heated installs for our LFP batteries. Can you cite some specific places you've seen this warning?

Several people on the forum have used variations of the tank heating pads intended to keep holding tanks on RVs above freezing. Others (including me) are putting silicone heating pads attached to aluminum plates to keep our cells above freezing.

My system will be installed in the basement of our cabin at 9,000 ft elevation in the mountains of Colorado. It stays below freezing in that room for several months during the winter. I will be posting details of my system at some point, but I think any of these approaches are probably better than using incandescent light bulbs.

 

[jlangri]

This will come as shocking news to many of us that have built or are building insulated, heated installs for our LFP batteries. Can you cite some specific places you've seen this warning?

Several people on the forum have used variations of the tank heating pads intended to keep holding tanks on RVs above freezing. Others (including me) are putting silicone heating pads attached to aluminum plates to keep our cells above freezing.

My system will be installed in the basement of our cabin at 9,000 ft elevation in the mountains of Colorado. It stays below freezing in that room for several months during the winter. I will be posting details of my system at some point, but I think any of these approaches are probably better than using incandescent light bulbs.

Most of the heating pads and blankets I've found have been on Amazon. Every one I've pulled up has had something similar to this one.

Amazon.com: Zerostart 2800055 Electric Battery Blanket Battery Heater Wrap, 28-Inch | CSA Approved | 120 Volts | 50 Watts: Automotive

Buy Zerostart 2800055 Electric Battery Blanket Battery Heater Wrap, 28-Inch | CSA Approved | 120 Volts | 50 Watts: Power Inverters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

In the description you'll find this: Notice: This product is NOT recommended for use with lithium ion batteries, nickel cadmium batteries or with battery case material ABS

https://www.amazon.com/dp/B07H2ZZ3NY/ref=cm_sw_em_r_mt_dp_2W36ENDKTGA6QNEMY8K8

Once again, in the description: Notice: This product is NOT recommended for use with lithium ion batteries, nickel cadmium batteries, with battery case material ABS or for use in an insulated battery box

I'm a bit of a newbie with working with batteries as expensive as these and prefer to extra cautious. Since they don't spell out the dangers, I may call a couple of manufacturers if I have time and have them explain why they warn against using these products for Lithium batteries. Perhaps used in conjunction with thermostats, they may be acceptable.

 

[Horsefly]

I don't doubt that there are some products with that warning. But it sounds almost like you are looking for that warning. There are lots, and lots, and lots of stories here in this forum of people having implemented methods to keep their cells warm.

Take a look at this thread: https://diysolarforum.com/threads/lifepo4-heating-pad-for-cold-temperatures.5/

22+ pages. Certainly there are some ideas there you can use.