Motor usage question on 5s lipo
 

Ok, I have a question for you guys.

I have a LS10 truck that I am currently running a hacker 13l on 5s lipo thru a quark 65.

If I was to go down to a hacker 15l and continue running 5s and the quark 65 and alter the gearing so that it retains the same top speed would it drawn less amps.

I only ask that due to fact that it appears the more voltage is applied to a motor the more current it draws (to a point). So I figured that a lower kv motor with higher gearing would pull less than the ligher kv motor with lower gearing. I am not sure if this makes sense.

I would have to go from the current 14t pinion to a 16-17t pinion to retain the same top speed. The 13l is around 1850kv and the 15l is about 1650kv. Let me know what you think. I am trying to get a setup that will pull around 40amps and not peak over 90amps. The truck is reasonably light and the battery is a 3000 5s maxamps(not the best cells!)

I dunno about 6S, but I'm running a 15L in my T-Maxx.. on 6S normally and 8S when I want to show off a bit... it runs very nice on 6S, and must draw very little amps because I'm only using 6S1P 2200mAh 20C, cheap hong kong batteries... even on 8S everything stays cool... it should draw less amp on the same gearing but you'll lose out a bit on speed... maybe try running 6S on the same gearing... is that quark capable of 6S?.. I've never used a Quark ESC before...

Well, the peak amps will be less, of course... but, it will theoretically take longer to get to top speed... it's hard to tell. But, I think the Quark 65 should be worked equally as hard on both setups.

Ok, ZPB, you think that the lover kv will be offset by the higher gearing thus not really affecting the amp draw? I wondered about this, as the motors are somewhat close in kv. Does it matter how fast the motor spins? Is there a rpm point where bl motors are more effecient? I know that it is generally said to keep most bl motors under 40k rpms for better effecientcy, but is there a point if the motors spins too slow and the effecientcy drops?

Well, yes and no... the peak draw SHOULD be lower, with of course less 'power' at the wheels. It's complicated, there are actually a few factors that would determine which would be better, for general use. Most BL motors have 'ideal rpm ranges', Neu motors seem to have the most usable, and broad rpm range for practical use.

For reference, my Revo with a 7XL motor on 5s2p A123 (~4s lipo), geared for 45mph, I get 130 amps peak draw... and I know people with a 9XL geared for the same speed get less than 120 amps, I am pretty sure.

But, again, it is usually hard to determine this... as these motors we are using have 3 times the torque that will keep the wheels on the ground, thus making for too many variables to take into account.

Theoretically though, a motor of lower Kv. on the same voltage as a higher Kv. motor WILL draw less current.

This might be confusing some people... :neutral: