2S vs 3S run times?

[Hickoryhead]

I am going out limb here so correct me if I am wrong Brian but the way I see it if you are running the same motor and ESC and the difference is gearing and batteries then no your run time will not be similar. Batteries are all made the same. The number of cells matters but a 2 cell vs a 3 cell 3500 mah battery will last the same amount of time. The difference will be in the voltage which can change your handling factor. ie jumps, cornering...

With this being said then:
1: no it wont. You changed the gearing factor which took away the voltage advantage you gained with the 3 cell. But it should run cooler. (I think)

2: No. Same as above.

Hope this makes since. I have been up for 38 hours so far.

[zeropointbug]

Correct ME, if I am wrong. But your runtime will go DOWN when running 3s over 2s setup... higher voltage will allow more current, and thus exponentially more power (volts x amps= watts). This is according to how anyone would drive a BL truck (handfuls of throttle)... however, if you hold a constant speed (say, to hold same speed for both 3s and 2s), or drive it the same as 2s, the 3s setup will have a longer runtime.

[GO-RIDE.com]

Originally Posted by zeropointbug

Correct ME, if I am wrong. But your runtime will go DOWN when running 3s over 2s setup... higher voltage will allow more current, and thus exponentially more power (volts x amps= watts). This is according to how anyone would drive a BL truck (handfuls of throttle)... however, if you hold a constant speed (say, to hold same speed for both 3s and 2s), or drive it the same as 2s, the 3s setup will have a longer runtime.

That was my theory, but the only indication I have is that the packs I quoted are nearly the same size and weight. I'm guessing they have the same # of lipo cells, they are just wired differently. One is a 3100 3s and the other is a 4200 2s.

[GO-RIDE.com]

For conversations sake, let's say I used my above example except that:

1. I optimized each motor for the voltage of the battery and thus used the same pinion for each setup to reach my 35mph top speed.
2. As stated before I would drive each car the same pace around the track.

Would this allow the 3100 3s to have as long, or nearly as long, of a run time as the 4200 2s?

[Hickoryhead]

I think it would come down to how you drive the car.

[BrianG]

Originally Posted by Hickoryhead

I am going out limb here so correct me if I am wrong Brian but the way I see it if you are running the same motor and ESC and the difference is gearing and batteries then no your run time will not be similar. Batteries are all made the same. The number of cells matters but a 2 cell vs a 3 cell 3500 mah battery will last the same amount of time. The difference will be in the voltage which can change your handling factor. ie jumps, cornering...

With this being said then:
1: no it wont. You changed the gearing factor which took away the voltage advantage you gained with the 3 cell. But it should run cooler. (I think)

2: No. Same as above.

Hope this makes since. I have been up for 38 hours so far.

Maybe I should have been more clear.

Yes, if you go from 2s to 3s on the same exact setup, runtime will be lower. Of course, the car will go faster as a result. But, if you only apply the throttle so it is as fast as the 2s setup, runtime will be about the same, minues any difference due to the added battery weight.

If you changed the motor so you get the same total rpm with 3s as you did with 2s, then runtime will go up. If you keep the same motor, go to 3s, but reduce gearing, runtime should go up. It's all a matter of the amount of work the motor is forced to do.