BMS and Chargers for Lithium Batteries

tscott

I'm starting to do some homework for converting my cart to lithium. I'm leaning toward 2 Chevy Volt 48v packs in parallel because they can be had fairly cheaply. My questions concern chargers and BMS systems. How are these generally wired? Do the BMS systems and chargers have 2 leads for every cell or do them manage the pack as a whole? As I look at BMS systems it appears most max out around 15 cells. If I was to run 2 packs in parallel, I assume I would need 2 BMS systems to manage all the cells? Does that sound correct? If this is the case it might be cheaper to go with a pre assembled pack with BMS already built in from someone like EV Battery Center.

Tom


Sent from my iPhone using Tapatalk

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

Sixshooter44

Are you looking at the packs from the guy on eBay? The prices make them very attractive

FireFighterHill

Which BMS are you looking at? Web Links? Id love if someone made up a DIY from start to finish using both the chevy volt and Nissan Leaf modules.

Bop4

I will add to DIY kit suggestion how to test lithium batteries from a wrecked Volt or Leaf sold by a auto recycling center. I would prefer to buy locally so that I can test the batteries on site prior to purchase or possibly purchase with a warranty to allow time to test off site.

PingEye3

Bop4: Just how do you go about 'testing' the lithium cells / pack at the Auto Salvage before purchasing it?

Bop4

Pingeye3, that is what we are asking. How do you test the LI batteries? If the cases are physically undamaged, could the battery be damaged on the inside of the case from the wreck from a short in the electrical system or from the sudden impact? How do you test the battery to determine the remaining service life? The remaining service life will affect the value of the battery.

PingEye3

Nick @ EV Battery Center receives complete packs from the auto salvage industry. Once he has disassembled them, each cell is bench load tested. He also does this with each of the BMS that he sells. Each BMS is connected to a pre-wired test pack and put thru his tests. Once he tests and calculates the AH of the cells, he prices them accordingly. Less $$ for older cells that still test very good at high capacity, but not at 'new' cell capacity.

When you buy a 7 pack of cells from Nick, they will usually arrive at very near the same voltage of around 3.95V per cell. It is a good resting voltage for the cells and when you make the final connections for the first time the pack is nearly in balance from the start. There is just no way to test a pack at the auto salvage yard, other than checking for total pack voltage of around 385V.

Hope this helps.

Gregorio

If the prices appear to be really good, it is probably from a guy that is known in all the EV forums to be a scammer or at least very unreliable. He has been banned from most of them. Be careful out there.

FireFighterHill

I saw on ebay the entire battery pack from a chevy volt for about 1600 bucks, would be able to do at least 2 to maybe even 4 carts with one pack. I just need to figure out where to get a compatible BMS and how to wire it correctly. Ive already found compatible lithium chargers. I think I can figure it out, but id rather not be the Guinea pig.

Gregorio

Orion is the most popular but Elithion has some interesting custom solutions.