BMW lithium batteries??

[josh843]

Been looking at going lithium for a little while as my T1275’s are just about shot. Came across these today and was wondering if anyone had any opinions on them? Obviously would need a BMS and a charger, but other than that look to be a decent deal if they can be hooked up in series. Also have a higher amp discharge rating than the leaf batteries. Cart is a 2016 rxv with tuned 235 Curtis.

[dronning]

One issue might be the Maximum Current discharge is only 180A. I've read discussions on only having a max 200A discharge may cause issues. Which would have impact on hills and acceleration.
- Dave

[josh843]

Originally Posted by dronning

One issue might be the Maximum Current discharge is only 180A. I've read discussions on only having a max 200A discharge may cause issues. Which would have impact on hills and acceleration.
- Dave

Yes, however there are several people running the leaf packs that only have 130 dischagre with no issues, vs the 180 of these. I figured if anything these would be an “upgrade” at least on that front, over the leaf packs.

[Sergio]

The Leaf lithium cells have considerably more discharge than 130 amps, not sure where you got that value.

The "continuous" discharge is not a big deal as even upgraded carts use less than 150 amps during cruise speed.

The important number is the peak discharge and duration time as even stock motors can use upwards of 300 amps for several seconds during acceleration.

Most of the issues experience by folks with integrated packs is related to the BMS inability to sustain peak discharge current.

Having a good programable Controller like Alltrax that allows you to set Motor and Battery current independently help mitigate some of the issue with those packs.

[josh843]

Originally Posted by Sergio

The Leaf lithium cells have considerably more discharge than 130 amps, not sure where you got that value.

The "continuous" discharge is not a big deal as even upgraded carts use less than 150 amps during cruise speed.

The important number is the peak discharge and duration time as even stock motors can use upwards of 300 amps for several seconds during acceleration.

Most of the issues experience by folks with integrated packs is related to the BMS inability to sustain peak discharge current.

Having a good programable Controller like Alltrax that allows you to set Motor and Battery current independently help mitigate some of the issue with those packs.

Thanks for clearing that up for me Sergio, I saw somewhere on some website that it had the maximum discharge for the leafs at 130, may not have been “peak” discharge and I’m not even sure what generation leaf it was that I was looking at. Is there anyway to easily find what the “peak” discharge would be on these BMW batteries? I would imagine it’s a fair amount higher than the maximum discharge, and also how do you think these would work with the zeva BMS?

[Sergio]

This site say they are good for 600 Amps for 10 seconds, that is more than enough for a good acceleration.

https://batteryhookup.com/products/b...35161014894754

Zeva is a nice BMS but the complete setup is on the upper range of prices typically used for golf carts.

You need to make sure they include balancing cables to make the connection to the cells easier.

You need to find a good central location to place the BMS in order to keep the balancing leads somewhat even.

You need to be very careful not to disconnect the batteries from each other if the BMS leads are still connected to the BMS or it could cause an issue with the small gauge wire used for balancing.

It will not be the easiest setup to implement, I prefer individual cell/modules like the Leaf or just buy new LifePO4 cells like many users are doing now and You will have a better system that those pre-fabricated units with unknown components inside.

[morvolts2]

I have nothing to add,other than make sure you sandblast the entire battery compartment.
I used 1/8 inch aluminum plate cut the same size as the battery rack to fill the holes and allow for some wiggle room.

[jhornbr225]

Yes, I agree.

I don't know about the sandblasting. I suppose since all the wires and components will be out of the cart, that would be the time. However, I am not looking to do a body off frame restoration. I was actually surprised how solid everything was in there, just surface rust.

At minimum, I want to hit it with a wire wheel and some paint. Maybe some of that POR-15 stuff, I've heard good things.

Obviously, all of that after any metal mods that need done are completed.