On 9/25/2021 7:06 AM, tb wrote:
David, What are ballpark costs for that Li conversion? Thanks. Thon
The 5s batteries were about $220.00 each, so to start, that's $440.00. [I forget what the hipping was] The BMS - I spent a load of time searching for one that would work. It's easy to find super expensive ones more meant for off grid homes. Like over $1000 expensive. It's also easy to find cheap crap ones that are too low cost to believe, or just plain old too small for this project.
I ended up with a Chargery one, and their Solid State Relay disconnect that is rated for 200Amps. I didn't like that it's a made in chine thing, but the only ones I could find that weren't were the crazy expensive home ones. Anyway, As I expected, I did some re work and minor improvements to the Chargery system, and it has been working so far. The changes were to check and add some insulation between the circuitry and the cases, since some clearances just were not great. Also had to shave off a little bit of a heat sink with my milling machine to get a proper gap between it and the case. The cases are all metal, and their instructions say to keep them electrically isolated, which is nuts, thus the insulation check and improvements. The Chargery system was about $350.00. It is programmable for the type of lithium batteries you get, and you can set all the parameters for over / under charge, temp, current, etc. It also has a passive balancer built in. So far, it has been doing ok also.
One thing to be very aware of is that some of the BMS ratings get played with - The SSR I have is rated for 200 Amps - but only for 10 minutes. 100A continuous. Since I typically see 40-60 A mowing, It's ok. The times I remember seeing around 100A [about full scale on the ET Ammeter] was heavy wet snow blowing, but I use my Dynahoe for snow removal these days.
Total cost was around 1300 +/ - 15%. Not including what ever you do for the lift motors, lights. A Cheap set of golf cart batteries I could get at BJ's were about $110 each, so $660. But I *might* get 5 year out of those. I haven't had great luck with LA the last couple sets.
Dave