lithium batteries

I also use three 24AH LiFePO batteries to power the trolling motor on my canoe.  Very light weight and yet there is lots of power right up to the point where they are almost completely discharged.  I use a 100 watt solar panel and a charge controller designed for LiFePO charging to keep the three batteries charged up while I cruise around in the canoe.  When I put these away for the winter, I disconnect them from everything, and when I come back to them the next summer they still have a full charge. I've never been able to do that with any deep cycle lead-acid battery that I've used.  I've always had to either put them on a trickle charger or hit them every other month with a regular charger. 

The 24AH batteries have built in battery management systems (BMS).  I really like having them.  That helps to protect the cells inside the battery.  I also have a NOCO charger that does a great job with the lithium batteries.