Transitioning to LiFePO4 batteries and XM1000 Pro

[BobC]

Originally Posted by Tgbyrne716

Aren't the 2 x 110Ah = 220Ah functionally limited to 110Ah? I've read that repeated full discharge damages the batteries quickly severely limiting the life of the batteries.

Yes and no. Routinely discharging below 50% will, in fact, reduce your lifetime cycles and routinely discharging below 50%, will give you a fewer number of cycles. Going below 50% will not "damage" your battery. Most battery manufacturers will state that discharging to 20% of below will cause real "damage". This may seem to be a semantic issue but it's not if you consider that routinely discharging less than 50% will give you longer life. 50% is a number that's been chosen as a happy medium in terms of maximizing life cycles vs. the inconvenience of having to charge too frequently. Many battery manufacturers publish graphs of this. Here's one site that compares the effect of discharging by 30% to discharging by 50% in terms of lifetime cycles for various brands:

https://medium.com/@gridfree/how-to-...e-4c3aad4f6035

You'll see that, if you discharge by 30% (70% state of charge) a battery will last about twice as long as it would if you charge it to 50%. That doesn't mean that charging to 50% damages the battery.

There's an interesting discussion of this in this IRV2.com thread starting in post #23:

https://www.irv2.com/forums/f56/firs...-535245-2.html

[BobC]

I found this chart regarding Trojan T-105 batteries:

https://ressupply.com/documents/troj...E_Brochure.pdf

Keep in mind that this is based on routinely discharging to the level in question, not occasionally doing so. Let's say you boondock once a month for two or three days and discharge to 30% state of charge. I doubt that you'd even notice the reduction in life.

It's all a matter of balance.

[Fanrgs]

Originally Posted by Tgbyrne716

Aren't the 2 x 110Ah = 220Ah functionally limited to 110Ah? I've read that repeated full discharge damages the batteries quickly severely limiting the life of the batteries.

Yes, if you are talking about 12v FLA, Gel, or AGM batteries. No, if you are talking about lithium batteries. Lithium batteries can be discharged 100% and are half the weight of FLA batteries. So you get twice the usable amp-hours at half the weight with lithium. Check out the 12v 105Ah LIon Energy Safari UT 1300 LiPO4 batteries sold by Costco. That's what we have in our motorhome and they work very well.