I've been running my LiPo system for the 24V Currie for a couple of weeks.
I'm using Hobby King 3s and 4s 5AH Turnigy packs configured 7s3p 15AH.
Fits in the Currie box.
BMS schematic and PCB attached.
Uses an Arduino Nano microcontroller.
Here are initial limits I've set:
High cell V charge cutoff: 4.25V
Low cell V charge disable: 3.0V
Low cell V discharge cutoff: 3.2V
Low pack V discharge cutoff: 24V (3.4V per cell)
Low pack V discharge warning light: 24.5V
Charge to 29V (4.15V per cell)
Schematic doesn't show 0.25A PTC polyswitches on the balance lines and 9A PTC on each string output.
Parasitic drain is 100uA. PWM Shunt balancing during charging to 20mV. Shunt current ~400mA max.
The PCB has 6 jacks for the balance connectors.
Pack weight 8.5lb.
Questions or suggestions welcome.
I would use a HVC of 4.15V instead
Motorcycles: 2011 ZEV Trail 7100, 84V, 60AH, 60+mph, Cycle Analyst, TNC throttle, modified charger. 2013 Kymco GT300i
Bicycles: 2017 Sondors Thin
Cars: 2016 Leaf SV, 30KWH pack. 2007 CR-V
Solar array: 5KW. Cost per lifetime KWH produced $0.073
Bi
Sorry, I did revise that to 4.2V.
The charger stops at 4.15V per cell average.
The 4.2V is for an individual cell, which would only happen if there's a problem with the balance circuit.
The cells never routinely go over 4.15V +/- 20mV