Maddness

[jagboy]

I was looking at using two 3080s to power an electric kart, but I couldn't find an ESC that could handle the voltage and amperage. I checked out the Power Jazz, but it can only handle 120 amps. If you used all 120 continuously and 63 volts, you could only produce 7560 watts. You need a 63 volt controller that can handle 160 amps continuous to produce 10kw. Schulze has two that can handle the amps (Future 32.170 and 40.160), but they fall short on voltage. I'm sure that there is an industrial company that has one, but I dont know of any controller capable of handling it. I'm sure there is one out there or else Lehner couldn't sell any of their 30 series motors. The car would have to be built around the motor. I dont think any current production car would be able to take 10kw even with upgrades.... maybe the Baja 5B. That would be incredible! Anyway... sorry to be the bearer of bad news, but if you find a controller please tell me. I'm always looking for stuff like that. If I find one, I'll tell you.


JB

[BrianG]

It might be easier to simply get a small low current/voltage ESC and then add as many output FETs as needed to handle the current. You'd basically just be using the input decoder circuitry (from the transmitter) and the "programming" from it. The voltage capacity is limited by the choice of FETs. Yeah, it would be clunky and rather large - not like the nice neat little ESC we are used to...

[jagboy]

Hmmm.... could you elaborate a little. I hate messing w/ electronics (especially such crucial and intricate ones), but this intrigues me.


JB

[BrianG]

Originally Posted by jagboy

Hmmm.... could you elaborate a little. I hate messing w/ electronics (especially such crucial and intricate ones), but this intrigues me.


JB

By any means, I am not saying this will be easy! This is rough breakdown of what I'd attempt:

- Use the "brains" from the small ESC. If I was really good, I'd redesign all the circuitry for the receiver input, programming, and CPU control - but I'm not that good, so I'd cheat. :)

- Create a V/A amp (voltage and current amplifier) that will amplify the signal voltage to the battery voltage and amplify the current to 200A or more.

- Since the needed battery voltage (>50v) is quite a bit higher than the small ESC could handle, I'd initially bring the high battery voltage into the V/A amp and then also regulate it down to 8v to send to the battery input of the small ESC.

- Feed the three motor wire outputs of the small ESC to a voltage amplifier so the voltage is as high as the high voltage from the batteries.

- Then, use as many MOSFETs in parallel as needed to achive the current you want (>200A). Due to the way MOSFETs work, they can be easily paralleled. The devices would not be surface mounted, but typical TO-220 cases properly mounted to a heatsink. As you can imagine, the resulting

- Add some protection circuitry to the battery input and motor output of the small ESC so that if a problem occurs with the seperate V/A amp board, the ESC will still be usable.

- Use 6 gauge wire for the power, and 8 gauge for the final motor outputs.

I just wish I had a BL ESC to spare so I could experiment, something like the Mamba is pretty cheap at $80, but too expensive to just experiment with. Since it's not going to drive a low impedance load (V/A amp will take care of that), it won't even need a heatsink.

There are a few disadvantages to this:
- The V/A board will end up being rather large.
- The batteries that can supply this kind of current and voltage would be something like 4 or 5 car small batteries in series, which would be heavy!
- It would have to be a fairly large truck 1:6 or 1:4 scale to fit all the components and use driveline parts that won't shred with the torque!