Hi Jim,
If you are going to use a DC/DC converter instead of a 12V battery you may want to fit a separate switch on the 72V battery supply to the DC/DC converter so that it doesn't draw current from the battery when the bike is not being used.
If you wired a 12V relay to the ignition switch output wire so that the relay contacts automatically closed when the ignition was turned On, the relay contacts could then be used
(instead of a separate e-lock switch) to activate or deactivate the contactor according to the ignition switch position.
You could probably repurpose the engine kill switch to turn the DC/DC converter On and Off, as switching it off would instantly stop the DC/DC 12V output, which would effectively turn off the ignition supply, causing the relay to open and deactivate the contactor as well.
You would need to use a 72V contactor to connect/disconnect the battery to/from the controller, which would be wired as shown on the left hand side of this diagram:
The obvious difference would be a 12v relay being used in place of the e-lock switch shown.
You could also use a 12V contactor fed directly from the 12V ignition switch
(instead of the 12V relay and a 72V contactor) but the orange e-lock wire going to the controller would need to be connected directly to the battery + terminal on the contactor for it to still work as per the above diagram.
I am still unsure as to whether this controller actually has a built in
precharge function, as the e-lock wire on the "WITH CONTACTOR" diagram is supplied with battery voltage
before the controller receives full battery power
(via the contactor) whereas the "WITHOUT CONTACTOR" diagram appears to be the exact opposite.
Alan
