I might have over est how much power I will need

[saltydawg]

Saltydawg,

"just turn on the mat, sure you burn 3 ahs but you can at least charge it"

That is great to know. Charging a lifepo4 in cold weather has been a stumbling block for me. ... but no longer.

I always learn good stuff from your posts!

Thank you

Edit and putting it front of the post, hopefully people would know to put the warming mat under the battery, in direct contact. just adding this because........

Yes basically you buy a 12 volt mat, linked one below, if your on shore power its not really a loss of power, you would just use the charger to power it. Now if your on solar or charging while towing you turn it on an hour or two before the sun rises or before you drive to warm the battery. Yes it could take longer is its really cold, but the one below is 12 watts, if you used 2 ( I would use 2 they are cheap ) you would use about 2 amps in an hour to warm the battery for an hour. Hopefully in this situation when the sun comes up you still have 2 ah left in your battery, but if your killing it 100% overnight you have more issues than the cold, ie need more battery. Now if your battery in say in a battery or tool box upfront you would want to insulate the battery so it warms faster. Easy way is just build a box out of foam that fits the battery, if its inside not really an issue.

https://www.amazon.com/GAOHOU-Electric- ... olt&sr=8-2

[saltydawg]

Okay I talked my self into it, I just bought 2 of those heating mats, one for each battery. Sense my batteries are inside, and sitting a foam panel floor I figure 1 for each battery will do nicely.

[saltydawg]

God I need to stop re reading the posts because every time I do I come up with something else that needs to be in here, but dont want to edit because people wont see it.

The thing with lithium batteries life is capacity, same as lead acid. When people talk about life span, it deals with capacity.

I have seen tests where people who live off solar and they stressed the heck out of their lifepo4 batteries. After 2 years of draining the battery 90% everyday still have 75 to 90% of the capacity. That would kill a lead acid in the 2 years, sure they are cheaper but you need twice the number of amp hours and the batteries would still be at 50% stated capacity ( or 25% useful ) . You will see a lot of end of life lifepo4 batteries on ebay from medical equipment, they are at 50% capacity ( you may not know it ) but they still have 1000 charge cycles, just at 50% capacity. Where as a lead acid battery at 50% capacity ( 25 useable ) is considered basically trash.