Great point. I had forgotten that some of the pre-builts do not handle being wired in series. I'm also in complete agreement with the rest of what you said.If you need 48v, then get or build an actual 48v battery. Some manufacturers are OK with series connecting their 12v LiFePO4 batteries, some aren't.
I doubt that the 280 Ah cells will fit your compartment, but just for comparison, I bought eight 280 Ah cells (including shipping, taxes, fees) for just over $900. That's 2.8 times the capacity of a 100 Ah cell for about the same money you're looking at in an off-the-shelf battery.
If it was me, I would max out the available space in the compartment with the largest cells I could buy.
Yes, it's allowed up to 48V by the manufacturer. I won't be bogging down if I have full voltage. That couple second 100A draw was when I was reading 40-44V. I'm expecting these batteries to average around 50A and peak at around 80A worst case. There really is no point in going past 100AH. I'm cutting 1.25 acres of grass and that will likely get me cutting 4 acres with 100AH Lithium. I also can't wait until mid-summer to get the batteries. I briefly looked at 120AH cells from AliExpress (recommended by Will on his site) that could ship from US but I'd be at $1700 just for the cells. And then I'm not sure what to build the box out of. Is it OK to use Wood? Really, capacity above 100AH does nothing for me. $900 for cells sounds good for cells but how long would that take to receive?
Fine. Your onboard mower charger might be becoming flaky, or in many cases inadequate to start.Thanks. I'll do that. I need to take it apart to get the true measurement of the compartment anyway. They always sit on the charger as recommended.
NO, do NOT run them all the way down. Simply charge each one up *individually* with an external charger once. Use a decent one, not a wall-wart. Set for agm (I'm assuming they are agm and not gel) That will bring them and their internal cells into balance. Now operate as usual, and use the mower charger for regular storage and charging, because individually charging every time you want to mow is not practical!I measured voltage and they were all even at full and at "dead" using the regular charger but I assume that it will balance on draw anyway. How do you recommend I do a proper balancing? Should I run them down and then fully charge using an external charger?
I just don't want your grass growing too tall while you are shopping for LFP!
Thanks for everyone's help on this! I ended up getting in on a group buy discount with Michael and went with Ganfeng 100AH cells and an Overkill 48V 100A BMS. I'm currently searching for an ABS flight case that I might be able to use to house everything. Excited to get everything!
Are you by chance the guy who hit me up on craigslist for the blue 90ah cells I have a few months back? Someone was doing the EXACT same project you are, and lives close by..... I live in Ohio....
Believe it or not... usually it's way cheaper.Nice picture. Yep. That's exactly it. But 280ah! Damn... I'd be able to cut the whole neighborhood with that. That would seem to be expensive no? Any suggestions/links on a low cost 100ah+ cell and a a good housing that I can strap these together in?
When I was looking into an electric mower I kept balking at the lead acid batteries in the ryobi.No, that wasn't me. That's pretty funny though. I'm still waiting on the cells unfortunately. I ended up going with an overkill solar 16S 100A BMS. It will be plenty. It's 100A continuous and peaks much higher than that for up to 30s. I have the BMS and a Pelican case that I'm using to house everything. All I have is a shipping label thus far.