2 brushless motor wiring?
12-05-2009, 02:51 PM
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2 brushless motor wiring?
I have a C160 Transall that I'm converting to electric. I plan on using 2 Hoffman Magnetics HMI-I 15 Outrunner 950kV motors. They call for a 45-60 amp ESC. I hate to pull that much current (90-120) out of one battery AND if I put a seperate battery on each ESC I stand the more risk of one motor shutting down before the other if the batteries are not perfectly matched. Can I put the ESC inputs in series to two batteries? What is the best way to wire them up. On my C130 (15 years ago) with brushed motors I ran a 2 sets 2 parallel in series with each other and that worked fine.
12-05-2009, 03:33 PM
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RE: 2 brushless motor wiring?
I'm not sure what you mean by "the ESC inputs in series to two batteries"
A small parallel jumper between batts will keep them equal and balanced.
A small parallel jumper between batts will keep them equal and balanced.
12-05-2009, 03:55 PM
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RE: 2 brushless motor wiring?
The Battery leads of each ESC in series. With 2 ea. 3S2P LiPo's in Series this should (?) give 11.1 volts to each motor. Or a single 6S2P would also work. Either way the wiring would only pull a max of 60amps where with everything in parallel the wiring would have to pull 120 amps max which I would rather not do. Am I correct in my thinking?
12-05-2009, 11:34 PM
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RE: 2 brushless motor wiring?
Hurkeybird,
A couple of things to mention. When you wire batteries in series, you increase the voltage & not the capacity, (mah rating). When you wire them in parrallel you increase the capactiy & NOT the voltage. Two 3s2p say, 4200mah batteries, wired in parrallel = 3s4p, 11.1v 8800mah battery. Wired in series = 6s2p, 22.2v 4400mah battery. BIG diference! Also, just because the manufacturer calls for a 45 to 60 amp ESC, doesn't mean the ESC will draw that much from the battery. That is determined by the voltage of the battery, the size of the prop, the kv of the motor & how heavy you use the throttle. If a 45 to 60 amp ESC is reccomended, I'd go for the 60 amp just to be safe. If you wish to use two batteries, wire them in parrallel. Make a 'Y' , (if you're using deans), 2 male, battery leads soldered to a single female lead, black to black, red to red. This plugs into both batteries. The voltage is not increased but the capacity is & both batteries will be drained at the same rate. Then make another 'Y' just the opposite, a single male to 2 female leads. These will connect to your two ESCs and supply voltage to the motors. you will aslo need to 'Y' the ESC connectors together to provide a single input to the Rx. I'd remove the center pin, (usually red), from the Rx connection and power the Rx & servos with a seperate UBEC. Good luck.
Rick
A couple of things to mention. When you wire batteries in series, you increase the voltage & not the capacity, (mah rating). When you wire them in parrallel you increase the capactiy & NOT the voltage. Two 3s2p say, 4200mah batteries, wired in parrallel = 3s4p, 11.1v 8800mah battery. Wired in series = 6s2p, 22.2v 4400mah battery. BIG diference! Also, just because the manufacturer calls for a 45 to 60 amp ESC, doesn't mean the ESC will draw that much from the battery. That is determined by the voltage of the battery, the size of the prop, the kv of the motor & how heavy you use the throttle. If a 45 to 60 amp ESC is reccomended, I'd go for the 60 amp just to be safe. If you wish to use two batteries, wire them in parrallel. Make a 'Y' , (if you're using deans), 2 male, battery leads soldered to a single female lead, black to black, red to red. This plugs into both batteries. The voltage is not increased but the capacity is & both batteries will be drained at the same rate. Then make another 'Y' just the opposite, a single male to 2 female leads. These will connect to your two ESCs and supply voltage to the motors. you will aslo need to 'Y' the ESC connectors together to provide a single input to the Rx. I'd remove the center pin, (usually red), from the Rx connection and power the Rx & servos with a seperate UBEC. Good luck.
Rick
12-07-2009, 05:23 AM
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RE: 2 brushless motor wiring?
Since batteries usually deliver the capacity they are supposed to I would just set up each motor with their own ESC and battery. As simple as possible.
Then do the homework, check that the batteries take equal charge after flights to ensure both systems work equal. Have margins using both timer and a safe LVC.
The KISS-idea usually works
Then do the homework, check that the batteries take equal charge after flights to ensure both systems work equal. Have margins using both timer and a safe LVC.
The KISS-idea usually works
