When I am charging my GEM car, all metal is electrified and will shock me it I touch it. Its not a full wall outlet shock, Kida like half an electric fence shock. Everything from the brake lines to the steel baker in back is electrified. Ideas?
The frame will not be “hot” if ground in outlet and cord is good. It should trip GFI in any case.
If that checks out then you need to see if it’s an ac leak or dc. A meter or neon tester will show.
If ac, turn off circuits one at a time to see when voltage goes away. Test from frame to true ground. Water pipe, metal drain, etc.
I get the same when charging my lithium cells with a bench power supply and iCharger. As a precaution I have the PS and iCharger sitting on a thick rubber mat on the short bed of my E6s with the charging leads running to the batteries. I’m in the process of replacing my Delta-Q so I can’t say if it also occurs with the onboard charger. I thought I was imagining things at first but it’s definitely there and I was measuring voltage from the battery negative to the frame. I spent a few hours trying to find the source by disconnecting lots of things but wasn’t able to. I think I got to the point that the battery pack was fully disconnected from the car and it was still occurring. It seems to go away some time after I stop charging. I was leaning towards it being an inductive charge that builds up from all the charging leads laying on the metal short bed and running across the aluminum frame rails. I’d feel a lot better if I was certain of the cause.
There would be stray voltage between frame and B-. Treat it as high voltage, same as B+. No difference coming in contact with B- or B+. Very dangerous.
How dangerous is 78V DC? I’ve worked on 240V / 120V AC and have gotten the occasional shock. Of course it doesn’t feel great but not instant death if you get shocked.
I’m starting to dig around in my cart and just trying to understand the true danger of 78V. Are we talking a slight shock or instant death?
Most cases slight shock. My post was explaining that the full potential may be between frame and B- and/or frame and B+.
In theory, no current will flow to frame in an isolated system. The danger is that a path to the frame of either + or - can go undetected. So you don’t know, without testing, if one or the other is “hot”.
From NEC, " A grounded system is for the purpose of controlling the voltage to earth, or ground, within predictable limits".
In other words a 120v to ground system could in theory have 1,000s of volts to ground, by incidental leakage from high voltage sources. Distribution system primary voltage for example.
I’ve lost count of how many times I’ve been shocked working on this car. Fortunately it’s not too strong but definitely gets your attention. I’ve since been better about checking things with a voltmeter before sticking my hands in there.
Strange - I have started dismantling the whole gem to basically restore it. I have taken the hood and rear fenders off with the headlights and taillights disconnected. I just started charging it from dead and no current in the frame at all. I will check again after its fully charged. Yes Im the kind of guy that will tay up at night thinking about this lol.