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Big system upgrade - Diagram check

Block

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Mar 11, 2023
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Canada
Hi everyone,

Longtime lurker - finally doing a system upgrade. Hoping for a math/brain check.

I have a 32s winston260ah pack that I am replacing. 102v nominal.

I’m looking at purchasing 66pcs 280ah EVE cells and running them in 33s2p configuration, with a BMS capable of handling paralleled cells. Let me know if you’d recommend something besides an OrionBMS2

My load (traction motor mainly) pulls 170amps average, but can spike up to 400amps for 10-20 seconds. These EVE cells don’t have great discharge alone, but in the 33s2p config I’d have ~106v nominal at 560Ah capacity:

vanBATTERY-Layout2.jpg

This system is charged with an ElconPFC5000. Not entirely a solar setup, but these forums are the best EVE/CATL Lifepo4 updates. Will likely be Docan or Qishou cells.

Thanks for looking, let me know if cell connections/clamping, cell discharge, fuse placement, suppliers, bms look alright. Cheers
 
OK I have never gone to this level and still a few random thoughts.

The midpoint fuses are interesting. As long as that would not be an issue with the BMS, seems good.

Is the charging really at 120 volts? Puts the cells near the max of 3.650 and potentially induce an over volt unless perfectly balanced. Maybe the charging is a bit less or consider one or two more cell pairs.

The cell pairs could be a bit much for the passive balancing. Consider an active balancer. Also will save a ton of effort vs topping 66 cells.

I built two batteries with paired cells and used a single copper bar across the four cells to avoid the additional connections.

If buying cells today I would have the EVE with the factory aluminum block terminal. https://www.18650batterystore.com/products/eve-lf280k

Best of luck.
 
Thanks for the info, I will lower the Elcon charging curve to ~115v.

I just got the basically the same offer from Doncan and Qishou. They both offered the aluminum block terminals. The same double-lug that time2roll posted above. Anyone have any last minute words of wisdom?
 

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