U11 12S Multicopter setup.

K

kemmy

Member
Hi everyone.

I just wanted to ask and get some advice about a multicopter system I’m building. Basically I decided to use the Tmotor U11’s I bought a few months ago. The system will include these components listed below.

8x Tmotor U11’s in a X8 config.

8x Tmotor T70A PRO (12S ) ESC’s

4x 22.000 mah Tatu Lipos in a 12S config so it gives me 45V and 44.000mah
1x DJI WKM as my FC

Custom built power distribution board that can handle all that power 

XT150 Connectors for the PDB and lipos.

DJI Lightbridge

26” or 29” Tmotor CF props(Depending on their performance at “little” windy weather conditions I will either choose the 26” or 29”)

Apart from the props I have the rest.

Now here comes the problem that I’m facing and need help with.

What kind of power distribution would be the safest and best option to go especially when I’m dealing with 12S power; because Wookong M doesn’t support 12S power and I was thinking to use a separate power option for the WKM but then I remembered the problems that might occur if I have timing issues with powering both lipos at the same time. I then thought of using a high current BEC but couldn’t decide which one I should choose. I know you will probably say use DJI A2 but I did use it and I had to change them back to WKM due to stability problems. I still think WKM is much safer and I can trust it (at least until A2 is stable with proper firmware updates)

Can anyone help me with how I should wire the whole system. I’ve always built and worked with 6S systems.Just want to know what would be the ideal wiring option when it comes to 12S systems.

Ps: This will also be my build log once I start building the system.

Thanks.

Kemmy
 


K

kemmy

Member
Well I also think it would be a great project to work on but only after someone helps me out with the 12S config and what way I should connect my Wookong M FC to a 12S power system.
 

FerdinandK

FerdinandK

Member
To power the wkm I am using a small 4S battery. When powering up, there is no problem, I do first power the ESCs and second the WKM, also great for working with the Assistent, since with the WKM-power source only, there is no danger that the props start turning on your desk.

Power source should be as close to the consumers as possible, so since you have 4 arms and 4 batteries I would place each battery close to one arm and power the 2 ESCs from one battery. In addition you use (depending on your AUW and calculated for a connection loss of one battery) power lines between the batteries to equilibrate their voltage (and bkup a connection loss). I would never use a central power board, also you should never create a "ring" with the power lines.

Here an example with 2 points where batteries are bringing in their power:
powerdistrX16.jpg


Did you calculate you max thrust? You should be aware, that such a setup flown without (enough) payload has the potential of "fly away" in the sense of that you cannot descend, be careful at the first flights, a strategy could also be to test with 6S basic functionallity (props and command response) then 8S , then 10S and finally 12S.

Also I would strongly recommend NOT to use the lightbridge for the first flights, there is a deadband on the LB which makes "manual" control clumsy, especially when you are going to adjust the gains inflight. Be aware, that such a bird will not fly smooth (or fly at all) with the default gains, you need find them.

Good luck for your build and

best regards
Ferdinand
 

K

kemmy

Member
Thanks Ferdinand. This was the kind of info and chart I was asking for. :) I'll let you know more about how I get on once I get my parts from the CNC router :)

Thanks again.

Kemmy
 

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