Lock and Key

I have a 72v (20s1p) lipo system which powers a Cystalyte rear hub motor. To charge I unplug in two places. One is a grey single socket 75a Anderson connector. It's hefty. Then I unplug at the black and red 40a anderson plug which series 4 5s zippy lipo packs.
and plug in a parallel harness wired to a 206b icharger. The reason I keep the 75 amp Anderson connector is after charging I plug the black and red andersons back together first. I leave the big 75a Anderson unplugged until Im ready to ride so there is no current leaking off. If I replace the Grey anderson connector (which has one neg. and one positive wire going in and one neg. and one positive going to the controller) with a key switch will that prevent any current from being leaked?


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No, the switch cannot carry the current load. Your controller should have a smaller wire that you currently have wired in with your positive wire going to the battery. That wire is what supplies the controller itself, which draws less than .1 amp. Your keyswitch goes in that line between the controller and the positive battery supply coming from your main Anderson connector.

I never unplug my battery even if it sits for a month there is no problem, because the controller is turned off by the key, so it doesn't drain the battery. That key also works as an emergency cutoff, since a brushless motor (unlike a brushed motor) can't run without the controller turning the mosfets on and off to supply the correct order of pulses.

John

Thanks John,
I grok it now. One of the reasons I posted that question is because I couldn't understand how the wires in the key switch could carry the amps. So the key switch would replace the on-off button on the controller I have.

If I already had an on/off button, I'd put the switch in series with the button as a bit of extra protection. Just for piece of mind, before you hack into it check your the current with the switch on and with it off to be sure that circuit cuts the current to 0.

If you think at some point you may want to add a DC/DC converter for lights, fans, stereo etc., then you might want plan how you want to wire up the keyswitch. I use replacement switches from motorcycles, which have nice thick wires without the bulk of auto keyswitches. Pluse they're cheap, readily available and have decent keys. I run the supply for my DC/DC converter through the keyswitch in parallel with the power up line for the controller making it more difficult to forget to turn the lights off. If I also had a switch on the controller, then I could turn the bike off but still run lights or stereo which might be a nice feature I'd use occasionally. I don't have a switch other than the key, so I'd run the risk of someone accidentally hitting the throttle and the bike taking off if I wanted to use the accessories. The moto switches also have 2 sets of wires, though I don't use that option.

John

John, is that a 2 positon switch that stays on when turned? where did you get it? I just got one that is spring-loaded like a car ignition switch, only paid $ 6.00 on ebay but it's worthless to me. Thanks

geetarboy said:

John, is that a 2 positon switch that stays on when turned? where did you get it?

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I've gotten them from the local locksmith. It will depend if yours has a store and carries a variety of things, as this one does. Amazing the key related things he stocks.

geetarboy said:

John, is that a 2 positon switch that stays on when turned? where did you get it? I just got one that is spring-loaded like a car ignition switch, only paid $ 6.00 on ebay but it's worthless to me. Thanks

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Motorcycle parts stores. On my cargo bike I have one for a car, and yes it's spring loaded at the end of the rotation, but the intermediate stops also complete circuits too...1st position is accessories and 2nd position is ON with the final spring portion being to engage the starter. Those for cars are just more bulky with more metal, I guess to hold it in the steering column. The one you have is probably ok, and you just need to find the correct 2 wires.

Now I use keyswitches for motorcycles...a smaller assembly and no extra spring action, which is just wasted for our needs.

John