Difference between a 2s and 3s LiPo

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kV is basically how many 1000 rpm per volt.
 
OK so basically higher kv is a faster motor?

Theoretically. Given the same battery, yes a higher Kv will be faster.
(No load speed)
On 2s only:
2200 Kv =16,820 rpm
2650 Kv = 19,620 rpm
3800 Kv = 28,120 rpm.
4600 Kv = 34,040 rpm
The 4600 will most likely only handle 2s.
For 3S you would multiply the above rpm by 1.5.
As such for 4s, the 3800 would not work, as you would multiply the staTed rpm by 2. Most motors will max at around 60,000 rpm.
So on 2s, the 4600 would be the fastest. But jump to 4s and the 2650 is the fastest.
Another thing to consider is that as the KV goes down, torque generally goes up, all else being equal.
 
Theoretically. Given the same battery, yes a higher Kv will be faster.
(No load speed)
On 2s only:
2200 Kv =16,820 rpm
2650 Kv = 19,620 rpm
3800 Kv = 28,120 rpm.
4600 Kv = 34,040 rpm
The 4600 will most likely only handle 2s.
For 3S you would multiply the above rpm by 1.5.
As such for 4s, the 3800 would not work, as you would multiply the staTed rpm by 2. Most motors will max at around 60,000 rpm.
So on 2s, the 4600 would be the fastest. But jump to 4s and the 2650 is the fastest.
Another thing to consider is that as the KV goes down, torque generally goes up, all else being equal.
OK thanks guys. U guys are great. I think I understand this alot better after reading this thread.
So for speed I would match my battery and kv size to get close to 60,000r.p.m?
 
Umm in theory. Welcome to RCNT, and if you were to start a new thread telling what vehicle you have and your intended use, I'm sure we could help you much better! ;)
 
Ok. Will do. Great to be a member of this forum. Looking forward to learning more about rc cars
 
OK thanks guys. U guys are great. I think I understand this alot better after reading this thread.
So for speed I would match my battery and kv size to get close to 60,000r.p.m?
Also remember that the higher the kV of given motor, the less torque that motor has.
 
The different between 2s and 3s lipo is their voltage, You shold know that 1 cell=1 S= 3.7V, so 2s =7.4V, 3s =11.1V.
 
Yeah 3s is fun to have around for the occasional speed run, but for general use 2s will be more fun, less headaches and less money spent on spares and upgrades. Also some cars just become unstable at high speed. If you want to to faster without the extra power you can gear up (higher tooth pinion or lower tooth spur or both) as long as your motor is not getting too hot.

Or you can get high turn (or low kv) motor and low tooth pinion and make the 3s more manageable, but its still alot of power going through drivetrain...some cars handle it better than others!
 
Kv is rpm per volt...so a 800kv motor on 1 volt will turn 800 revolutions a minute.. or at 8.0volts it will turn 6400 rpm.....
 
Hello everyone. Nice thread. Learned alot about batteries.
But what is the kv rating?
What does the kv rating equal?
kV rating is for the motor. it's how many rpms the motor will turn per volt.
 
kv is say 4000kv and your running a 2 cell so thats 8.4 x 4000+ no load rpm or 33,600 revolutions per minute..now go down to 8 thats 32000 rpm i like to use the 8 to determine my fdr (whats that? ) final drive ratio.. very important when your trying to dial a rc car in...
 
2 cell LiPo is 7.4 volts.
3 cell LiPo is 11.1 volts.

Mah is milliamps.....or the battery's capacity. The C rating is how much your battery is capable of delivering over a period of time. If the C and mah ratings are too low you can watch your vehicle burn.
Congratulations on getting in to RC. It is lots of fun sbd there is always something new ( or very vintage ) to learn. I agree ! The C Rating is for high current short bursts. BE CAREFUL; usin higher S ( voltage) rating than recommended. You can burn up stuff including ESCs and motors. Assuming batteries of the same type and rating characteristics, TWO IN SERIES keeps the watt hour the same but doubles the available voltage while TWO IN PARALLEL keeps the same voltage but increases the amp-hour rating ( run time ). When building transmitter packs for my vintage tube radios, I put a bunch of 9vDC alkaline batteries in SERIES to get the low current drain high plate voltages I need for things like my CITIZENSHIP CC TRANSMITTER ( see PIX ).
 

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Sorry,. I should have read closer. My stupid mistake. Hope I have not offended.
 
But look... as with all things, a new conversation has sprung from a dead one.
 

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