FEVT ltd used latching contactors from Albright. http://www.albrightinternational.com/files/downloads/catalogues/SW80%20ETC%20TELECOM%20LEAFLET.pdf
You need to add a latching circuit when operating with low level BMS systems. When BMS keeps the contactor ON/pulled there is very little energy consumed. A simple trigger which is powered by few supercaps creates OFF burst when the signal from BMS is lost. Contactor controller can be programmed to sniff standard I/O's. We did the previously mentioned to cancel the current drawn from several contactors in a battery system. We used separate unit with PIC18F2480 SW/HW watchdogs. The distributed design allowed cross supervision over several CPUs with some redundancy. This topology allowed us to make systems which worked 10 years with next to none service (some SW updates were made to add redundancy). Winston's (aka TS) LFP-350AHA cells worked just as well that 10 years. By default there is build-in hand shake protocol over CAN bus between the main CPU and contactor controller. So if the CPU's SW (called Core SW) for some reason loses it's mind next controller CPU takes over the system control and initiates the preprogrammed CPU reboot sequence. Depending on the setup user does no even know there was a reboot done. So adding this to low level BMS you can achieve more stable and robust system. One neat feature was a timer code which basically allowed CORE to determine how many seconds the system may be on what ever is happening. Temperatures or voltages are not going haywire in few minutes. Say some of the electronics go broken. A divine touch or what ever is the reason. Contactor controller allows to operate the system over the set timer according the parameters. Naturally this controller may sniff all components on the CAN bus to determine if the timer was set right. I could make a patch of these contactor controllers if needed. I sold the company away in 2010 but I still know the technology inside out. Company wen't belly up over a year ago so I dare to use the system design now (?) I must say I'm stunned how long term technology investors did not know Moore's law. :) There was a lot of critics how expensive touch screens and multiple CPUs are and they will never be mainstream in vehicles. User interface development was scrapped because: "no one will use touch screens in cars. They distract the driver and are going to be forbidden by law". :D -Jukka http://www.google.com/profiles/jarviju#about 2014-09-17 7:26 GMT+03:00 Adrian DeLeon via EV <[email protected]>: > OK, it sounds like Steve is having a "phantom" current issue - the phantom > being a contactor that is always on. > > Are these packs plugged into the AC mains while sitting unused? I had a > similar issue with the 12V auxiliary battery in my EV. After about 4 days, > the 12V battery would go dead from the small but constant currents drawn by > the motor controller and mini-BMS board. I solved the problem with one of > these: > > http://batterytender.com/products/motorcycle/waterproof-800-usa-western- > hemisphere.html > > It's an 800mA trickle charger used to keep the batteries in ATVs and > snowmobiles from going dead while in storage. It's a smart charger, > weatherproof, isolated, and runs from 120/240 VAC. It came with both > alligator clips and a set of ring terminals. Mine is wired to the charging > plug of my EV, so as long as I'm plugged in, my 12V battery stays fully > charged. > > After retiring one of my EVs, I put the trickle charger to use on a 7AHr > gel battery that runs an automatic chicken coop door. The battery stays > charged and the door will still operate for days during a power outage. > > If keeping your packs connected to AC power while in storage isn't > possible AND this is a "run" contactor, you could wire the contactor coil > through a connector adjacent to the main pack connector. When connecting a > pack there would be the big connector (main pack) and the small connector > (a small shorting plug that would activate the contactor coil). > > If this is a charging contactor, find a way to power it via AC mains. That > way when the pack gets disconnected from the mains, the contactor will turn > off at the same time. > > -Adrian > > > On 09/16/2014 07:24 PM, Mike Nickerson via EV wrote: > >> 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) >> >> > _______________________________________________ > 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) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140918/82524df0/attachment.htm> _______________________________________________ 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)
