Can you run 2 motors from 1 esc???

[JIM MARCUM]

In theory, can you run 2 counter rotating brushless motors with a single HV ESC??? JIM

[Rumdog]

Fightercat sells one made to run two motors.

[Rumdog]

My question is, why would you want to?

[JIM MARCUM]

Why? Cuz I just bought an Apparition with twin motors & stinger drives. If one of my Seaking 180A ESCs can do the job, why not? I'll likely run larger Leopard motors later - which will require two 180A ESCs. JIM

[antslake]

Yes you can. There is a thread in rcgroups about it. I would search and read it first.

[antslake]

Wait, there is a thread here about it:
http://forums.offshoreelectrics.com/...t=no+load+amps

[Make-a-Wake]

Still dont see where it says you can run 2 counter-rotating motors............

[JIM MARCUM]

Thanks antslake for the link. Professor Joe is the brightest, & one of the nicest guys in FE today. He walks the boat talk big time.

But, that thread ended too soon. Still don't know the impact of matched motors running at different loads thru one ESC. JIM

[antslake]

It was discussed further in rcgroups I think. I asked the question about different loads, and to tell you the truth I don't remember all the answer right now, but it had something to do with sensorless motors, and having different loads did not matter. Believe me, I wanted to find a reason why it wouldn't work. Me personally, I probably wouldn't take the chance. I asked questions about efficiency and a few other things in that thread.
@make-a-wake, it does not matter which way they are spinning, you can do it. The thing is, that it is not really that cost effective to do so. You can get two turnigy 80amp esc's for the price of one seaking 180.

[monojeff]

Fightercat has 1 esc to control two motors.
FighterCat LV Marine ESC 6s 240a TWIN
Yes, one ESC, two motors. Each motor has its own MCU for true twin motor operation. Motors can work independently of each other under different loads, like a twin cat cornering.
Components are designed to handle 35 volts, FET's 30v. Realistically, 30 volts or 7s operating voltage. (6s preferred max)

* Max Constant Current: 150A Per Motor
* Max Current: 240A (burst) Per Motor
* BEC: 3.5a Switching BEC (Add a BEC Capacitor for large scale servos)
* PWM: 8 KHz 16 KHz 32KHz
* Input: 2 to 7s LiPo (6s preferred max)



Programming options:

* Battery Type, Number of cells/auto, LVC Voltage & Cutoff type
* Power Limit Forward & Reverse, 25, 50, 75 & 100%
* Throttle Curve, Logarithmecal, linear, exponential
* Acceleration, Soft, Medium & hard
* Timing in 1 degree increments 1-30 degrees (Timing is important to know, most 4 pole motors are 2-5 degrees)
* Delay time, .25S to 5S
* Timing Monitor, on/off (timing monitor will beep the timing setting when plugging in the ESC)
* Reverse, on/off

LINK TO TWIN ESC

[m4a1usr]

Still don't know the impact of matched motors running at different loads thru one ESC. JIM

Lets get to the details. First off,............you wont have matched motors. The production motors we buy are far from matched. They probably are close. Unless you dyno a group of them there are going to be differences which to the average person couldnt discern without professional tools.

Secondly,...............2 motors on one speedo allows for issues like differences in inductance (that causes timing differences). Then there are loading factors. (each motor sees different "water") we dont run in a static enviornment. Turning or changing direction is something we do quite often.

Lastly,.........with 2 motors you just changed the circuit IR. You 'halfed' it. Thats resistive load. So with a lower IR and the lower inductance you can see sync issues or even lock up of one motor. Not good. Especially on startup. You would never know you had a locked rotor situation as the boat would be away from shore.

You can do it. Lots of folks have. But if on the edge, you will pay, and dearly if you miscalculated something.

John

[JIM MARCUM]

According to Professor Joe "Questtec", his one ESC two motor tests showed only a 30% increase in Amp draw - not the 50% you would expect. The stock 2881KV motors on my Apparition cat are small so a 180A SeaKing ESC can handle it. that's 42,638 RPM with 4S2P. I'll do a follow up after I give it a few runs in stock form. I've ordered a R hand flex drive & have R/L Octura X430 props for a CR setup. I may try a 3S2P config. & drop in Leopard 2860 5050KV (56,055RPM, or 3660 4650KV (51,615). The Leopards are hungry so I'll go with 2 180A ESCs. JIM

PS: Using those high KV Leopards cuz I already have them. Would prefer to go lower KV & 4S2P config. Any body want to trade?