Help needed. Please forward to who might. DC ebike electrical advice.

This email was sent to my friends in Vancouver Canada, grin Technologies, the supplier and go go to place for ebike electronics in the world. But they are very backed up and I wonder if you know anyone that might provide Insight on the following.

Extreme every-other-day climbing ahead for months. This is the forecast here in Lone Pine. As the Heat and bugs rise the three miles up to the portal, 5 miles of 9 and 13% grade will be usual.

I think I'm all set, but if this is crazy please let me know. So far this morning it was tested and seems to be okay.

Bottom-line question, if with only one or the other receiving power, one positive input wire disconnected, the other controller connected to the battery, can I leave in place the FaZe Runner, and the old 40 amp controller phase wires connected in parallel to my mid Drive crown?

The grin fine controller seems to have found its niche, driving the crown in the rear wheel which goes at such horribly low RPM. It provides nice substantial power, no torque of course, and it does not overheat.

On the really steep climbs the old 40 amp controller driving the mid vehicle motor and I have way more than enough power. And neither overheats. Not appreciably anyway. But that combination is insufficient for The Descent, it cannot keep me slow enough with regenerative braking Beyond about 6% grade.

But the FaZe runner on that mid vehicle motor with the grin fine controller in the rear wheel has no problem keeping me at about 6 miles an hour.

So I've got the equipment the problem is, not at the same time.

I would have preferred talking to you all first but it seemed to me that if a controller was not receiving power, the red battery lead disconnected, it would be as though it were not in the system. Sorry if I'm giving you a heart failure but please let me know.

What I am needing is a way of quickly changing over the system from climbing mode to descending mode.

And my initial tests indicate that yes, based on temperature, the controller that is receiving no power from the battery, ground wire still connected but the red Power lead disconnected, the controller not being used space Stone Cold.

The questions I have which I pray you might have time to address.

1. Is this okay or is it a bad, bad bad, bad bad bad idea?

2. Can you think of a much better way for me to do this?

If it is okay:

3. Any idea where I can Source a switch that will enable me to select between power from the battery going to One controller or the other? The stuff I could get at a hardware store certainly wouldn't handle this amount of power.

4. If the paralleling of phase wires described above, and tried this morning, is okay, could I do the same thing by wiring up a parallel harness for the hall sensor wires?

In any case,

5. Can you point me to a way of hooking up a second temperature meter to the second motor not through the cycle analyst I'm sure, but can I do a external sensor so that I can watch both Motors? 

Thanks Friends. James