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Old 01-22-2008, 05:47 AM   #1
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Default NiCD/NiMH Voltage vs Lipo Voltage

Guys, i dont know if somebody asked this.

But what is the difference between the voltage of Nicad/Nimh and Lipo?

Say for example the Velineon:

it can run 6-cell 7.2 Nimh/nicad, also 7cell for 8.4V.
It also says it can run 3S 20C lipo which is 11.1V

So, can i use 9-cell 10.8 nimh on this ESC?
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Old 01-22-2008, 10:53 AM   #2
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Originally Posted by bryanleec View Post
Guys, i dont know if somebody asked this.

But what is the difference between the voltage of Nicad/Nimh and Lipo?

Say for example the Velineon:

it can run 6-cell 7.2 Nimh/nicad, also 7cell for 8.4V.
It also says it can run 3S 20C lipo which is 11.1V

So, can i use 9-cell 10.8 nimh on this ESC?
yes, lipo's are 3.7v a cell, and ni-mh are 1.2 per cell.
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Old 01-22-2008, 06:08 PM   #3
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So, can i use a 9 cell 10.8v nicad/nimh on that ESC?
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Old 01-24-2008, 02:11 PM   #4
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nine is fine.
The ESC doesn't care what type of battery is supplying that voltage.
Now another cell or two is going to weigh more, and make more heat in the motor and esc, and give you a lower run time.
I was just looking at the Castle Sidwinder specs and they show 3S and up to 12cells. given that, more than nine may be possible though i would tread with care.
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Old 01-24-2008, 07:45 PM   #5
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Default lipo on RX

Hi guys,
just wondering, i'm running nitro onroad with 3PK fasst and thinking of switching to lipo for my rx, some recommended to run with a regulator to bring back the voltage to 6V but i have seen some running without a regulator, 7.4V without any problem with he rx??? Any comments are welcome thanks,
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Old 01-25-2008, 02:38 PM   #6
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Futaba says '6.0v' for the RX. I don't think it would mind the extra voltage though. The problem is likely to be with the servos. Some servos become super servos with a little extra voltage while others burn up.
i'd run the external 6.v reg. unless you can find someone using exactly the same rx and servos without one.
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Old 01-25-2008, 08:26 PM   #7
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thanks for the info, i think i better use a regulator for safety of my servos
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Old 02-06-2008, 03:47 AM   #8
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Originally Posted by joe of loath View Post
yes, lipo's are 3.7v a cell, and ni-mh are 1.2 per cell.
Back to the original thread question, on my BL system, the specs says NiMh upto 7cells or 7x1.2=8.4v, but LiPo is 4S or 3.7x4=12=14.8. The question is, on my other ESC with spec of upto 7cells, can I use a 3S LiPo or 11.1v? I have lotsa 11.1v LiPo cells and tempted to use on my non-BL ESC which has no specs for LiPo.

The other thing is, NiMh when peak charged can go up to 9.2v for a 7.2v or 6cell pack. LiPo when fully charged is 12.4v tops. So, if the ESC max number of cell is 7cells and peak at 1.6v per cell, that will bring it to 11.2v. Would a 12.4v LiPo fry the ESC?

Hope someone have tried 3S LiPo on 7cell NiMh rated ESC.
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Old 02-06-2008, 08:38 AM   #9
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nice info
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Old 02-06-2008, 08:46 AM   #10
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Quote:
Originally Posted by etino View Post
Back to the original thread question, on my BL system, the specs says NiMh upto 7cells or 7x1.2=8.4v, but LiPo is 4S or 3.7x4=12=14.8. The question is, on my other ESC with spec of upto 7cells, can I use a 3S LiPo or 11.1v? I have lotsa 11.1v LiPo cells and tempted to use on my non-BL ESC which has no specs for LiPo.

The other thing is, NiMh when peak charged can go up to 9.2v for a 7.2v or 6cell pack. LiPo when fully charged is 12.4v tops. So, if the ESC max number of cell is 7cells and peak at 1.6v per cell, that will bring it to 11.2v. Would a 12.4v LiPo fry the ESC?

Hope someone have tried 3S LiPo on 7cell NiMh rated ESC.
that high voltage from the 6/7 cell pack will drop to the rated voltage within seconds of pressing the throttle, so the rated voltage is probably the max it can handle. saying that, i ran a cheapo RTR ESC on 8 cells and it seemed to work fine.

but you could do what i did and take a cheap ESC and put 3 cell lipo on it...
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Old 02-06-2008, 06:08 PM   #11
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Quote:
Originally Posted by joe of loath View Post
that high voltage from the 6/7 cell pack will drop to the rated voltage within seconds of pressing the throttle, so the rated voltage is probably the max it can handle. saying that, i ran a cheapo RTR ESC on 8 cells and it seemed to work fine.

but you could do what i did and take a cheap ESC and put 3 cell lipo on it...
I did a test on a cheap (but good) Moped Bravo v16 ESC on Tamiya Sports Tuned motor on M03R with a 2200mah 3S1P 15C LiPo. I first used a pack that reads 11.37v (75% capacity), no temp changes on the ESC and that motor rev like there is no tomorrow. Put under load, the motor heats up but the ESC is usual temp.

Next, I used a full capacity LiPo of 12.37v. The ESC still holds well and the car is insanely fast. I measure the current draw from the black can motor, it barely reached 10A on full throttle without load, so that explains the no temp increase on the LiPo (15C = 33A draw) and perhaps the ESC.

My next test would be to see how long would both the LiPo and ESC last with this setup. A 2200mah 15C 3S1P LiPo at my LHS cost only USD18. It is certainly a better option than NiMh packs.
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Tourers : Tamiya TA05, TA05R, F103GT, Yokomo MR4TC BD; HB Cyclone Hara Edition, TRF415 MSXXX
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1/12 Chassis : Kawada M300SX
Drift-Specs : Tamiya TT01D, TT01, TT01R; HPI Sprint 2; Yokomo MR4TC SSD Black Edition
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