HortonHCCI
New member
New to the forum.
So, I have a problem that some may find intriguing. I've built myself a little 1:4 scale RC model rowboat by taking the transmitter and 2S (7.4V) (brushed) Rx/ESC combo unit from a $40 Amazon RC boat kit, and paired it with a $20 12V brushed gear motor from Jameco. Amazingly enough, it actually works. Sort of. But if I limit myself to the 7.4V the Rx/ESC is rated for, it's slower and wimpier than I want.
So I want to use a 3S, 11.1V battery pack to drive the 12V motor, but I'm concerned about putting 11.1V through the Rx/ESC designed for 7.4V. I assume the answer is "don't do it." However, a curious fact is that the geared motor draws miniscule amperage--220 mA under max load. The donor boat's motor pulls 2A--might be 5A under load. So the motor won't fry; the battery won't fry; I assume my limitations are the ESC's capacity, and possibly the voltage in to the receiver.
The little combo unit is limited in that it has only power in, servo and speed-controlled motor out. So if I feed it 11.1 V, it might pass the 11.1V through to the motor, but fry the receiver, and/or it may just output 7.4V no matter what I feed it. Don't know what it's doing in there, and I don't really trust my very limited electronics smarts to tear into the thing.
So, two questions:
1. Would it be foolish to try to run 11.1V through the 7.4V Rx/ESC, given that I'm only running about 1/10th the amperage? and
2. If yes to the above, what if I used a buck converter to get the input to the Rx/ESC down to 7.4V, and then a boost converter on the ESC output, assuming it's 7.4V, to boost it up to 11.1V, or even 12V, to the motor? Lots of losses, I assume, but I don't care much, as I'm running just tiny amperage and power. As long as things don't melt.
Of course, I could use a separate 7.4V battery pack for the Rx/ESC, and use it to drive only the rudder servo, and wire the motor directly to a different 11.1V battery pack. I've done this, but it's heavy, and I lose the throttle and kill switch features of the ESC. I could probably run a wire from the 11.1V feed to a buck converter into the Rx/ESC to get servo only without the extra battery pack, I suppose. Still no throttle or kill switch, but at least I could steer around obstacles and come back home. Maybe.
I COULD just go old school, no throttle, no remote kill switch, no rudder. (i.e., no RC). And of course, I COULD just buy the proper matching stuff. But 3S receivers and brushed ESCs for things like crawlers look to be very expensive, and full kits/vehicles even more so. I want a lot of voltage and a LOT of torque on my little gear motor, and I want its full rated speed, so I want 3S, but I don't need anywhere near the power a typical crawler has. Partly, I'm cheap, and partly, it's the fun and learning of the thing.
Thanks in advance for any advice.
PS- Here's the gearmotor: https://www.jameco.com/Jameco/Products/ProdDS/253446.pdf
So, I have a problem that some may find intriguing. I've built myself a little 1:4 scale RC model rowboat by taking the transmitter and 2S (7.4V) (brushed) Rx/ESC combo unit from a $40 Amazon RC boat kit, and paired it with a $20 12V brushed gear motor from Jameco. Amazingly enough, it actually works. Sort of. But if I limit myself to the 7.4V the Rx/ESC is rated for, it's slower and wimpier than I want.
So I want to use a 3S, 11.1V battery pack to drive the 12V motor, but I'm concerned about putting 11.1V through the Rx/ESC designed for 7.4V. I assume the answer is "don't do it." However, a curious fact is that the geared motor draws miniscule amperage--220 mA under max load. The donor boat's motor pulls 2A--might be 5A under load. So the motor won't fry; the battery won't fry; I assume my limitations are the ESC's capacity, and possibly the voltage in to the receiver.
The little combo unit is limited in that it has only power in, servo and speed-controlled motor out. So if I feed it 11.1 V, it might pass the 11.1V through to the motor, but fry the receiver, and/or it may just output 7.4V no matter what I feed it. Don't know what it's doing in there, and I don't really trust my very limited electronics smarts to tear into the thing.
So, two questions:
1. Would it be foolish to try to run 11.1V through the 7.4V Rx/ESC, given that I'm only running about 1/10th the amperage? and
2. If yes to the above, what if I used a buck converter to get the input to the Rx/ESC down to 7.4V, and then a boost converter on the ESC output, assuming it's 7.4V, to boost it up to 11.1V, or even 12V, to the motor? Lots of losses, I assume, but I don't care much, as I'm running just tiny amperage and power. As long as things don't melt.
Of course, I could use a separate 7.4V battery pack for the Rx/ESC, and use it to drive only the rudder servo, and wire the motor directly to a different 11.1V battery pack. I've done this, but it's heavy, and I lose the throttle and kill switch features of the ESC. I could probably run a wire from the 11.1V feed to a buck converter into the Rx/ESC to get servo only without the extra battery pack, I suppose. Still no throttle or kill switch, but at least I could steer around obstacles and come back home. Maybe.
I COULD just go old school, no throttle, no remote kill switch, no rudder. (i.e., no RC). And of course, I COULD just buy the proper matching stuff. But 3S receivers and brushed ESCs for things like crawlers look to be very expensive, and full kits/vehicles even more so. I want a lot of voltage and a LOT of torque on my little gear motor, and I want its full rated speed, so I want 3S, but I don't need anywhere near the power a typical crawler has. Partly, I'm cheap, and partly, it's the fun and learning of the thing.
Thanks in advance for any advice.
PS- Here's the gearmotor: https://www.jameco.com/Jameco/Products/ProdDS/253446.pdf