Battery question

Originally Posted by suicideneil

Amps vs voltage concept:

power (watts) = volts x amps.

You need a certain amount of power to move any given setup to a certain speed.

If you use a low voltage, high current (amps) setup, it will run hotter and give less runtime compared to a higher voltage, lower current setup.

For example:

1000watts / 14.8v (4s lipo) = 67amps
1000watts / 11.1v (3s lipo) = 90amps

The more current you pull, the hotter the system will run, and the shorter the runtime will be, all things being equal aaprt form voltage.

That said, your 1515 1.5D would run equally well on 3s or 4s, you just have to match the gearing to the voltage to keep temps, speed and power in check.

I would peronally run 4s lipo, and gear down a bit to reduce the load on the electronics, yielding the best runtime, acceleration and power available.

ok...so on a 3S (40/80c TP 5000mAh) set up with an 11T pinion, the truck is frikkin nuts. wheelies galore, near backflips off the jumps (if i'm too heavy on the throttle on the face) and general mayhem going down the straight.

on 4S, it's even worse. front tires the size of paper plates, double backflips if I hold the throttle in the air off the jumps, and my drive train is screaming for mercy/vengeance.


So...would I need to gear up (say a 13-14t pinion) on a 4S while retaining the stock spur? Or do I need to gear down (a 9T pinion?) to help temps?

I'm lost as of now...the combinations I've tried usually end up in huge amp draws that make the motor quite unhappy.

the best combo i've found for a 3S with the stock spur is an 11T pinion. motor temps usually range from 123-126F, ESC (MMM) is around 125F, and batts are around 110F.

So...if I wanted to duplicate those temps on a 4S, what pinion would I need to run?

[Snipin_Willy]

Originally Posted by BUSAFIED

ok...so on a 3S (40/80c TP 5000mAh) set up with an 11T pinion, the truck is frikkin nuts. wheelies galore, near backflips off the jumps (if i'm too heavy on the throttle on the face) and general mayhem going down the straight.

on 4S, it's even worse. front tires the size of paper plates, double backflips if I hold the throttle in the air off the jumps, and my drive train is screaming for mercy/vengeance.


So...would I need to gear up (say a 13-14t pinion) on a 4S while retaining the stock spur? Or do I need to gear down (a 9T pinion?) to help temps?

I'm lost as of now...the combinations I've tried usually end up in huge amp draws that make the motor quite unhappy.

the best combo i've found for a 3S with the stock spur is an 11T pinion. motor temps usually range from 123-126F, ESC (MMM) is around 125F, and batts are around 110F.

So...if I wanted to duplicate those temps on a 4S, what pinion would I need to run?

123-126F is luke warm on a motor. My truggy is pushing 175 after 20 min mains of conservative driving. And I'm running a 1515 2.5D tekno neu. Ambient air temps were quite high though as well as humidity levels.

3s on a 2700kv motor is enough to race with. It pulls more amps than a lower KV motor on higher cell count, but that's where it's getting the power from. Until you're seeing upwards of what I'm experiencing, I wouldn't go to 4s unless you had a lower KV motor.

Originally Posted by Snipin_Willy

123-126F is luke warm on a motor. My truggy is pushing 175 after 20 min mains of conservative driving. And I'm running a 1515 2.5D tekno neu. Ambient air temps were quite high though as well as humidity levels.

3s on a 2700kv motor is enough to race with. It pulls more amps than a lower KV motor on higher cell count, but that's where it's getting the power from. Until you're seeing upwards of what I'm experiencing, I wouldn't go to 4s unless you had a lower KV motor.

hmm...i guess it's a 3S for this motor and the race, then.