Can a 48V motor controller work with 36V?

My Maine deep cycle batteries are delivering to much current thru thinner guaged wires...i have dc-dc step downs and a circuit breaker between batteries and motor controller however when i turn on... thinner wires are catching fire...i would upload pics but every time on a mobile device it rejects three pic...(can only be 15 kb)....can this 48V 750W vevor bldc brushless motor work with 36V ? Id use the other 12V battery separately )

First of all don't run a controller off a DC DC converter use a proper voltage battery bank. Hopefully you're not doing that and those are separate devices on the same bank.

Second, if the issue still exists after rectifying the above, run a proper gage cable. Easy.

Third, the controller will probably draw the same current on 36v if it runs.

years ago i ran a 24v controller on a 12v sla by hooking 8 aa cells in series with the key switch, so the logic circuit saw 24v, so the low voltage cut off would not kick in. worked fine.