Date: Tue, 25 Jun 2013 22:13:00 -0500 From: Lee Hart <[email protected]> To: Electric Vehicle Discussion List <[email protected]> Subject: Re: [EVDL] EV Digest, Vol 8, Issue 39 Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Mike Malmberg wrote: my responses below and thank you so much > coil has 14 volts The Tyco LEV200 data sheet says it has a 12vdc coil, and is rated for 9.6v minimum, 13.2v maximum. 14v is more than its rated voltage, so it would get hot. My suggestion would be to add a series resistor, with a capacitor in parallel (called a "slugger" circuit). Choose the resistor to drop the steady-state voltage a few volts. Oddly, the data sheet doesn't give the coil resistance, so you'll have to measure it or experiment to find the right resistor value. --So a series resistor on positve or negative side of coil. coil resistance measured with an ohm meter across the coil while the coil is off or energized? Is there some math I need to do to calculate the resistor value that I need? Then, the capacitor in parallel initially applies the full voltage, to make the contactor pull in quickly. Something like a 10,000uF electrolytic capacitor rated at 6vdc or more will do it. --And this capacitor goes across the coil of the contactor, yes? > I realize that the BMS should have control over that contactor, and so my > charger negative should go on the other side of the contactor (controller > side rather than battery side). Will that affect the contactor heating? No. You aren't running enough current for its contact to produce any significant amount of heat. > Also, nobody responded on the bms control question, I flipped the diode > the other way around and I have no throttle at all. I can't help you there. Sounds like you had the diode the right way to begin with. Was it in fact limiting the throttle when the BMS sensed a low cell voltage? --no that was why I started asking questions, it had no effect on the current output at all. when checking it the original way I had it hooked up, I believe I had 5 volts on bms side of the diode and 1.2 volts after the diode. Does that sound right? I have gone through the check that Orion recommended which was to pull the current sensor to see if the BMS responded and it did drop to zero volts. so full pack 5 volts and no pack 0 volts (.03v ) -- For every complex problem, there is a solution that is simple, obvious, and wrong. -- H.L. Mencken -- Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.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)
