Arducopter X8 behavior if only top or only bottom motors on

I am thinking about power redundancy on an X8 running 3.2. I am thinking of powering the top and bottom motors from separate batteries, so if one fails it can hopefully at least allow a safe landing (my x8 used to be a quad, so only has to lift the extra weight of 4 motors and power train, so should be ok power wise at least to land).

but before I get too far down an avenue, I would like to know if it would fly (my x8 conversion hasn’t flown yet as I am still developing…fiddling with it, so not done any experiments). Does the control system use both top for all control axes? Will the control system even know what to do if only top or only bottom sets are powered.

I like the idea of separate power over paralleling batteries, as one battery may drag the good one down in a fault. I don’t want to diode the power either as the escs I use have active free wheeling regen that puts current back into the battery (although I imagine the net current flow is still out with all the others consuming, but it could regen I guess if altitude bumps)

If the control side is feasible, I want to develop a power module that powers the brain from either battery.

Although it might be a good idea for me to do some flight tests on a small quad set up with the correct motor directions/order for a top and then bottom layout with x8 firmware to see what happens…but it would be nice to know I’m not on a wild goose chase first.

Cheers

Stu

Great minds think alike… :slight_smile:. That’s the setup I went for also. I have a QAV540G that I modded into an X8 for which the top and bottom 4 rotors each have their own battery. Only have 3 test flights on it so far but seems to work great! When plugging in just one battery, it’ll fly fine (at much higher hover throttle of course) in either top or bottom-quad configuration. Using the Pixhawk for the controller. Running 3.2 (though that really shouldn’t matter).

Note that I chose to power my controller from a separate 5V BEC (I don’t like to use the ESC-ones). This BEC itself is fed from both batteries through a diode (a Smartfly BattShare). Hence, if one of the batteries fails, my controller and RC will remain powered up.

[quote=“Gra55h0pper”]Great minds think alike… :slight_smile:. That’s the setup I went for also. I have a QAV540G that I modded into an X8 for which the top and bottom 4 rotors each have their own battery. Only have 3 test flights on it so far but seems to work great! When plugging in just one battery, it’ll fly fine (at much higher hover throttle of course) in either top or bottom-quad configuration. Using the Pixhawk for the controller. Running 3.2 (though that really shouldn’t matter).

Note that I chose to power my controller from a separate 5V BEC (I don’t like to use the ESC-ones). This BEC itself is fed from both batteries through a diode (a Smartfly BattShare). Hence, if one of the batteries fails, my controller and RC will remain powered up.[/quote]

That’s great news, Cheers Gra55h0pper. Yeah I don’t like using the esc becs either (actually my escs don’t have a bec). I will be doing the regulation too so that its also diode ORed.

Cheers fella.

Stu

Are both batteries using about the same amount of charge?