A123 BMS Testing
I plugged one of my packs into my CC/CV 2A charger today and topped it up.
I have found the A123 BMS is active and it has started to bleed off current. I'll check the load switch on voltages etc as we go.
The pack must have been full when it arrived. It also means if your packs are very low you should probably disconnect the bms parasitic load.
The load for each channel is made up of 8 x 91R (910) marked smd resistors in parallel = 11.375R effective resistance.
At 3.65v that gives a balancing current of ~320ma at 1.1w which seems reasonable.
The BMS pcb has two active leds I can see. I will watch to see when they go on and off.
They are on at the moment but the cells had reached ~3.90v and the pcb is now quite hot as it is disipating ~15w from the 14 channels.
All the channels/cell groups seemed very well in balance in this first pack.
I'll try and identify the other black BMS connector as it may be possible is is now also active and sending data or warnings.
At a pinch it might be possible to use the led/s to drive an external circuit by connecting directly to the pcb or by hot gluing an opto transistor on top of it Edit. The leds on the bms pcb have turned off and the bleeding of current has stopped now cell groups are below 3.85v.
Honda Insight MK1 lmpg 131mpg Imp
Lifepo4 40ah HiPower IMA Pack & 20ah A123 IMA Pack
BCM Fooler, BCM Interceptor, BCM Gauge, Li-Ion BMS System, OBDIIC&C, IMAC&Chttp://www.150mpg.co.uk