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Old 01-04-2003, 04:41 PM
actofgod actofgod is offline
Bit Surgeon
 
Join Date: Sep 2002
Posts: 216
Quote:
Originally posted by SPEED
Also, what type of POT would you have to use if you wanted to put this into a 1 cell bit??? Thanks!
Plug in 1.2v for 2.4v:

Resistance (ohms) = 1.2v / 0.275 amps (1 milliamp = 1000th of an amp) = 4.36

To half the speed, you'd need 8.73ohms; to half it again you'd need 17.45ohms. Actually, these are the numbers I used by mistake when selecting a pot rating for the two cell mod the first time. A 20 ohm resistor would work just fine for both; you may just have a little smaller "usable speed range".

Incidentally, a 20ohm would work on a 3 cell mod too, it just wouldn't slow it down as much. You'd need 26.18 ohms to half the speed at 3.6v, so you'd be able to tune it from a little over half speed to full 3.6v speed. Still a useful addition.

I think this mod is most useful for two or more cells, though, since going below 1.2v not only sacrifices torque and acceleration but if you go low enough could affect your steering coils' effectiveness and the ability of the car to receive the signal from the transmitter. A slower engine is probably the best way to slow down a one cell car, unless you're trying to race on a single paper plate.
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