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4dollarjoe
27 May 2015, 0918
So while working on my bike I decided to reconnect the wire to my contactor so I could cover that section of the bike with my hallowed out gastank.

While trying to put the motor plate in I felt what could be described as a really minute shock, like after pulling my hand back I was debating if I was actually shocked or had some fear reaction.

I had both motor leads dangling on the inside of the frame, I tried moving them and boom; ****ons of sparks that when up some of the battery brackets and looked to end at my ipod amp which has a metal housing. Not sure if that is still going to work, haven't touched it because I was afraid it had some charge left in it.

Afterwords, I disconnected the contactor part and forced one of the motor leads to contact the frame, more sparks but with me finagling with it for another 10 seconds didn't yield any sparks. Did the controller possibly hold charge after I disconnected it and discharged to the frame in that instance?

I think I'm just gonna reconnect my motor and leave it on a chair to the side with terminal covers to prevent this from happening when I try placing the motor in.


Honestly I feel a bit ignorant towards keeping myself safe, arcing is really unpredictable and scary to me. I was planning on working another two or three hours but after that incident I just felt like quitting for the day. It was probably my fault, I've heard to disconnect the batteries always when working but I was ignorant and figured that the free hanging motor leads wouldn't have any bite if the controller was off.

Is getting shocked working on this such a big deal? I really don't want to be a noob and harm myself, already enough bad EV press out there. I heard it takes around 40 amps to kill someone but the bike isn't drawing current (at least significant) while it isn't moving. Even if I get shocked from the 67v from my batteries, the current can't kill me unless I connect myself directly to the circuit during use, right?


Basically I'm wondering, were those arcs I saw really dangerous; or was that minute shock essentially me touching an arc and it isn't something to worry about?

Other than disconnecting the battery, what else can I do to keep myself safe? I usually only work with one hand to prevent any shock from going across my heart already, any other suggestions?

Lex
27 May 2015, 1045
Anything above .2 Amps (200mA) can kill you. Always check to make sure what you are working on isn't live with a multimeter. Maybe there is a capacitor somewhere that isn't discharged. I'm in school right now and some motors have smoothing capacitors or something to give them a better power factor (efficiency?) Do you have some kind of disconnect or way to isolated from the batteries?

Lex
27 May 2015, 1050
Actually I think the capacitor is for the start winding in a DC motor which phase shifts it with the run winding creating an opposite magnetic field to each other. I'm sure someone in here knows better than I do. But I will re-iterate don't work live.

podolefsky
27 May 2015, 1139
Disconnect the battery, let it sit for 30 minutes before working on the bike. The controller has capacitors in it that can stay charged even when you remove power.

The best way to disable the battery is to remove a cell-to-cell jumper mid pack, so that even if you happen to touch the main terminals you can't get a complete circuit.

If you can't do that, disconnect as close to one of the battery terminals as you can and wrap it in electrical tape. Also make sure the pack isn't grounded to the frame.