- Joined
- Jul 31, 2012
- Messages
- 61
Hi ; after putting this bms (https://bmsbattery.com/bmspcm/330-smart-bms-513-cells-in-series-bms-pcm.html#/212-discharge_current-20_40a) on a 12s battery from a chevy volt pack, I want to make a 18s setup so putting two in series. The bike has a 500w controller.
On the charge side, I have 3x meanwell hrp-300-24v in series (each charging 6s) and I can supply both bms independently (I know the bms cuts at >5A and comes back on, it's ok for me for now).
I'm more worried about the discharge side ; I read on different threads that flyback diodes are required at each discharge fet (https://endless-sphere.com/forums/viewtopic.php?f=14&t=90476&p=1319696&hilit=relay+contactor#p1319696), also read that people create an and-gate by powering a relay coil from each bms and when both n/o contacts are made (https://endless-sphere.com/forums/viewtopic.php?f=14&t=48461&hilit=and+gate+relay), that turns on a contactor with a resistor in parallel for pre-charge.
Would that schematic be safe and functionnal?
Also, about coil voltages, my 6s would be 24v, my 12s 48v, but for the contactor should I go for 60v or 72v? Are those (https://www.aliexpress.com/item/SAYOON-SZ10-150-150A-contactor-DC-72V-contactor-used-for-electric-vehicles-engineering-machin/32792798156.html) any good?
I dont intend (yet) to push it at more than 10A... is the contactor really necessary in this case or some 40A car relays can do the job?
On the charge side, I have 3x meanwell hrp-300-24v in series (each charging 6s) and I can supply both bms independently (I know the bms cuts at >5A and comes back on, it's ok for me for now).
I'm more worried about the discharge side ; I read on different threads that flyback diodes are required at each discharge fet (https://endless-sphere.com/forums/viewtopic.php?f=14&t=90476&p=1319696&hilit=relay+contactor#p1319696), also read that people create an and-gate by powering a relay coil from each bms and when both n/o contacts are made (https://endless-sphere.com/forums/viewtopic.php?f=14&t=48461&hilit=and+gate+relay), that turns on a contactor with a resistor in parallel for pre-charge.
Would that schematic be safe and functionnal?
Also, about coil voltages, my 6s would be 24v, my 12s 48v, but for the contactor should I go for 60v or 72v? Are those (https://www.aliexpress.com/item/SAYOON-SZ10-150-150A-contactor-DC-72V-contactor-used-for-electric-vehicles-engineering-machin/32792798156.html) any good?
I dont intend (yet) to push it at more than 10A... is the contactor really necessary in this case or some 40A car relays can do the job?