You're right ! I went experimental on this one today... Went skydiving this noon. Went for burgers and beer after. Then, I came back home, I hooked up my batteries and went riding from 8:45 to 10:20 PM. I did exactly 30 km.999zip999 wrote:Matador where's the 7s balance wire's for a cell checker ? Bms or not. You need to know.
Started at a 58.1 V charge (around 95+ % SOC)
Ended at a 52.1 V charge (around 50-60% SOC)
I didn't take the time to hook up my BMS or to hook up a cell log.
Note that it's at 52.1V now, I will not bulk charge it... I fear some imbalance might result in some P groups being overcharged.
Temps have reached 60-65°C... But feeling with my hands, I know it comes from the cells, as they are hot, while the connectors screw and bussbars felt barely warm if not just ambiant temp. BUT hey, that's to expect from 10 years old laptop cells ! Just the 14S8P cells inside the pack, togoether cause around 250 mOhm (calculated, from individual cells DC IR)...
I checked each cell with my mastercraft multimeter and cool them with a fan now. I read from 1S to 14S
Note that before starting (58.1V), some cells were at 4.17 while others where 4.12 V...
I will balance charge with an Imax B6 tomorrow when I can supervise... Then I could hook a BMS... Or just trash these old laptop cells and use my VTC4 (but they're good to up to 30A/cell !)
Anyways, in this experiment, using my 30A BBSHD (60% of time at PAS2/5 (600W) going 35 km/h, 25% at PAS 5/5 (1500W) going 50-52 km/h, 15% time Throttle mode only on the 5/5 setting 55-60 km/h), the Vruzend kit won the battle over the cells themselves... Love it !