[fstop]

I’m interested in going with a lithium pack in my Onward. I’ve tried to absorb some basics from numerous build threads but am still fuzzy on much of it. Appears Leaf cells are a common way to DIY, and probably within my capability if I knew enough…
So, a few questions regarding the following:

1) 7 (or 14) Leaf 8v cells
2) BMS (Chargery BMS16T, Zeva unit…)
3) Output fuse, Protection Contactor / Solenoid x2 (is there a difference?)
4) Charger
5) Mounting frame for cells, brackets for additional parts like solenoids, BMS
6) Sources for 1-5?

1 – eBay availability is primarily “70% + life remaining” – obviously used batteries, but does this mean 70% of AH delivery per charge available, or 70% of # original charge cycles remaining? Is there a source for new Leaf cells? Most listings indicate maximum discharge of 120a I think – is this sufficient for high performance GC motors? Obviously 14 cells provides more range and potentially better performance – I think I’d need 14 as my stock pack has limited range when using speeds above 19mph or so… I guess for that matter you could use 16 cells? I think the BMS16T can do that many? (My controller / motor is good to 72v…)

2 – Lot’s of variables here I take it… BMS ideally should monitor each cell or cell group for over or under voltage, and monitor (and control via simple solenoid disconnect) total pack current delivery and total pack charge current. So if charger goes rogue and tries to charge to voltages that are too high, the “charge side” solenoid disconnects. If there is a short on the output, or controller or motor fails in some way, the “load side” solenoid disconnects pack from the situation. Or the output fuse blows – do you need both?
Does the BMS balance the cells in some way by bleeding off power from cells that are higher into cells that are lower, or reducing charge to cells that don’t need it and directing to those that do during charge? What happens if a cell voltage is too high or too low – can the BMS do anything about it besides alert you via beeper or screen? Then what do you do about it?
What about Regenerative braking? (I’ve got a CC Onward with a Navitas AC drive system in it) Doesn’t the regen current come in to the “output” side of the battery pack? How does the pack / BMS deal with that?
What is the consensus on powering the BMS? Power with the total pack voltage or via a DC converter (the one on my cart for lights etc…)? Power it with its own dedicated battery? What is a “sleep switch” for?
I wonder what the EZGO and Club Car factory Lithium pack approach is regarding BMS / charging, etc…

3 – What is the coil voltage needed for these – is it total pack voltage or some setting within the BMS (since I presume it is what is controlling the coils of these solenoids…)

4 – What kind of charger is preferred on these installs? Is it connected via the BMS, or just to the “output” side of the battery? Does it communicate to the BMS or does the BMS just somehow stop current flow to cells that are too high during charging and allow others to continue?

5 and 6 – I don’t have a machine shop handy, and don’t want to re-invent the wheel on all of these things – is there a source / sources for all of the “stuff” needed to cobble all this together so it doesn’t look like a science project gone wrong under the seat? I’d like to make the whole unit fairly easy to remove with only a few wire disconnects if that’s possible.

Thanks for any links or other advice - obviously I've still got some reading to do on all this.