I have a Mini BMS system also. I suspect the contractor might be for charging circuitry. I have the same issues with an SSR in my system.
The Mini BMS is set up to terminate charging if necessary when a cell is over voltage and the ignition system is off. It does this by turning off the SSR or contactor on the AC line to the charger when it detects a cell alert with the ignition off. When you turn on the ignition system, it re-arms the contactor back to on, to prepare for the next charge cycle. The problem is that the contactor stays on all the time the vehicle is parked. On my car, it takes about 2 weeks to drain the auxiliary battery. I solve this by pulling the fuse to the EV control circuits which includes power to the SSR. I've wondered if there is a better way too. Mike On September 16, 2014 7:02:41 PM MDT, Lee Hart via EV <[email protected]> wrote: >Steve Clunn via EV wrote: >> I am working on some Golf Carts and portable 12V power packs that get >used >> sporadically and may sit for months without use. >> >> I have contactor on one 12V and 36V that draws about 1 amp. The >problem >> is, if everything is happy, the Mini BMS Circuit keeps the contactor >ON. >> Which draws enough current, that at some point, will drain the >battery down. >> >> I am trying to come up with a way that the owner can walk away from >this >> system, and come back to it and have it ready to go without having to >> switch switches OFF and ON. > >Steve, could you elaborate a bit more on exactly what you need to do? >My >impression is that you have a 36v pack, with a contactor to connect it >to its load. You don't want to have an on/off key switch; just hop in >and drive. But that would mean keeping the contactor on all the time, >which would run the pack dead? > >The best I can think of is something like a seat switch. When no one is > >sitting on it, the switch opens and turns the contactor off, which >removes all loads from the batteries. When someone sits on the seat, it > >turns on the switch, which turns on the main contactor, and away you >go. > >Another possibility is that Albright (and others) make latching >contactors. There is a magnet as well as the solenoid coil. The magnet >is sized to hold the contactor on (once it is already on), but not >strong enough to pull it in (if it is already off). You then pulse the >coil with a positive pulse of current to turn it on, or a negative >pulse >of current to turn it off. In both states, the continuous power >consumption is zero. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
