Dig with 2 different ESCs

[Digger94]

I know this sounds kind of frankenstein but I have put a Novak goat on my front axel and a cheap acme ESC on the rear axel. I am letting the Goat BEC power the radio and servos. I removed the red wire from the acme speed controller so it should just drive the motor. Now the problem is this all works for a few minutes and then the rear acme ESC wont run anymore. I get a blinking light and no power. I realize that this is some kind of safety but it is not heat. The thing is cool. I have also tried another ESC I had here and it worked in a similar manner. Worked for a few minutes just fine then the power out to the motor stopped.

I am running an 8.4 V battery, a Novak Goat Brushed, 2 55T motors, 2 small servos less than 200 oz., Spektrum DX5 radio.

I am trying to get this thing working for a comp in 2 weeks help, please.

I dont think I will be able to run out and get a second Goat and if I did would I have the same problem? It probably has to do with the second ESC being Crap but what is the actual cause? Servo current draw? Any ideas? Would a BEC make this all work?

[Charlie-III]

Does the Acme ESC have a LiPO cutoff built-in? If so, what is it set for? Maybe it is set for a 4S and you are running 3S so it cuts off??

[beidave]

Maybe post a sketch of the wiring, or a decent pic. That may Help.

[Digger94]

I looked through the instructions and found no mention of lipo at all. The two cheap ESCs I tried were

http://gateway.selltec.com/elements/...d/etcrtr_e.pdf

http://www.etamiya.com/shop/apex-ele...ke-p-7718.html

and here is the goat

http://www.teamnovak.com/download/in...at%20Instr.pdf

I will do my best to descrive the wiring since it will take a while to draw but here goes.

One battery pack (8.4V) "Y" out to both ESCs (Goat and other).
Goat runs front axel and has all three transmitter wires going back to the throttle of the receiver that came with the DX5e.
The servo for the front axel also has all three transmitter wires going all the way back to the receiver and is plugged into the rudder.
The Acme ESC is hooked to the power "Y" from the battery and in on the rear axel. Only the black and while wires of the transmitter wires are going back to the receiver. I thought it was a voltage feedback kind of problem or something. That ESC is plugged into the elevator on the reciever.
The servo for the rear is using all three wires back to the receiver and is plugged into Aileron.
What confuses me is that it works for more than 3 or 5 minutes then just stops putting out power to the motor. Sometimes sooner but not more than a few minutes. The battery pack is good I can see the voltage on my charger before and after a run.
Could it be something with the frequency of the PWM? I saw it listed on the ACME ESCs but not the goat. I will try to make a drawing not sure how to post it. Neebie.

[Digger94]

Hobby store guys think I need a second battery for the second speed controller. That sounds wrong. Any feedback on that?

[Digger94]

Two battery packs fixed the problem. Voltage drop???
I guess I will need to run 2 packs till I figure out if I can just use a capacitor to keep the ESC from freaking out or I get another Goat to go with the first one.

[Charlie-III]

Originally Posted by Digger94

Two battery packs fixed the problem. Voltage drop???
I guess I will need to run 2 packs till I figure out if I can just use a capacitor to keep the ESC from freaking out or I get another Goat to go with the first one.

I'm still wondering if the Acme has a LiPO cutoff in it. The 2nd battery pack may be enough for it to work now, but just about everyone else running 2 ESC's just run 1 battery pack.

[beidave]

Glad you figured it out, you might try a lipo with a 25 or 30c rating. That should also fix Tue problem.

[Charlie-III]

Originally Posted by beidave

Glad you figured it out, you might try a lipo with a 25 or 30c rating. That should also fix Tue problem.

Running 2 packs is a "patch", not a true resolution. There should be no reason to run 2 packs, once he figures out the real issue.

[Digger94]

I agree patch not solution. Hope it is enough to make it through the competition this Saturday at Motorama here is PA. If not I will need to put it all back on one ESC and lose the dig stuff. After that I plan to get another Goat and see if the problem just goes away with 2 goats instead of one goat and one kid (small ESC).
IF I can get a scope working over here maybe I can see the problem.
I really wish I had seen someone else here with a similar problem and solution.

Thanks guys for your help!

[beidave]

Originally Posted by Charlie-III

Running 2 packs is a "patch", not a true resolution. There should be no reason to run 2 packs, once he figures out the real issue.

As is the two different esc's a patch. If the battery does not handle the running load of the two motors it will drop voltage to the further, or larger load and stall or drop the esc.