Alan B wrote:I would use Leaf battery components, or similar available from other existing automotive designs that are available on the used market.
That is my plan also. Like also the chevy volt and the larger ford c-max cells. The C-max have built in fuses so all I would need to setup is a balance charging setup. I can get a big pack for around 1K on the salvage market. I need to make charging and battery monitoring idiot proof as the spouse will be the main user. Just a work cart so It should be good with 12s, but thinking 14s may be good also. The stock batteries are still healty so I have the time to think it through. Know very little about the subsystems so far. Need to get a shop manual to learn all the subsystems and relay connections. The winch setup is powered by two separate six volt batteries up front. Not sure if anything else needs them. Looking at a 48V Ware winch or swapping out the motor for a small BLDC and reversible trike controller if I can find the right shaft setup. I am wondering the need for a separate Lead battery setup at all. Charging a separate Li 12v pack setup (automatically from the main pack) if need be would be the main concern if I try to keep the 12v winch setup.
Update: What a great UTV! Spouse loves it also. Battery box can fit a boat load of Li capacity. Stock batteries are still acting near new. Will see how it winters over in use. At a closer look it measures out to easily be able to fit 6 (or possibly 8 if you want killer range) chevy volt 2kwh sections. Will be a interesting project swapping over to a Li pack on it.
Looking for some sort of battery charge / voltage display that can show individual series cell strings adapto style. Simple led voltage indication strips for each string would be good. Hate to go with just a gross idiot light setup showing low battery or a simple but effective pack voltage indicator.