May 16, 2011, 08:27 PM
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Mitchie | |
Mitchie Registered User Thread OP | Discussion Hi everyone, I have a newb question. I have a heli running 3s batteries & motor now, but had 2s originally. Can I use the original motor and esc (2s)with my 3s batteries? Or do I have to get 2s packs? |
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May 16, 2011, 08:36 PM
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ScooterInVegas | |
ScooterInVegas Village Idiot! | It all depends on what the motor and ESC will handle. Going to 3 from 2 cells adds 50% more voltage. That means more speed and more amps. If you running a 3 cell now, and the motor or ESC hasn't given up the smoke, I say keep doing it. Dot be overly surprised if you cook one or the other though. |
May 16, 2011, 09:09 PM
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Mitchie | |
Mitchie Registered User Thread OP | Actually, the setup now in the heli is 3s. The original (which I have) I was thinking of re-installing. I do not have 2s batteries. That's why I was asking the question. Will I kill the esc if I put it back to original and use the 3s batteries? Or will I have longer flight time and lower head speed. |
May 16, 2011, 09:21 PM
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mjsas | |
mjsas Registered User | Quote: Originally Posted by ScooterInVegas It all depends on what the motor and ESC will handle. Going to 3 from 2 cells adds 50% more voltage. That means more speed and more amps. If you running a 3 cell now, and the motor or ESC hasn't given up the smoke, I say keep doing it. Dot be overly surprised if you cook one or the other though. Actually the speed and amps depends on the flying skills, for example at hover the amps would be the same for both 2s and 3s. The main difference is the voltage and how well the 2s stuff can handle the higher voltage. Also the BEC would most likely be a simple linear regulator which hates higher voltage. In the end it will either be OK or go up in smoke. Just about all FETs and voltage regulators have 12 or 15 volt ratings. 8 volt stuff is rare. |
May 16, 2011, 09:30 PM
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Mitchie | |
Mitchie Registered User Thread OP | What I got out of that was pretty much, probably bad! Bout got it covered? |
May 17, 2011, 12:19 AM
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ScooterInVegas | |
ScooterInVegas Village Idiot! | Quote: Originally Posted by mjsas Actually the speed and amps depends on the flying skills, for example at hover the amps would be the same for both 2s and 3s. With the throttle cures set the same and throttle hold ON, the heli would pull more amps with a 3 cell over a 2 cell with the same settings. |
May 17, 2011, 12:22 AM
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ScooterInVegas | |
ScooterInVegas Village Idiot! | Quote: Originally Posted by Mitchie Will I kill the esc if I put it back to original and use the 3s batteries? Or will I have longer flight time and lower head speed. Run time is dependent on mAh rating and amps pulled. Yes, you would have lower head speed. You have not given any info on the battery capacity, motor, esc or make or model. There for, we can only guess.. |
May 17, 2011, 07:14 AM
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Dave Lindsey | |
Dave Lindsey Registered User | "Run time is dependent on mAh rating and amps pulled. Yes, you would have lower head speed. " Whoa, something's not right here. Electric motors are rated by kv, i.e. rpm's/volt. As an example a 1000kv motor will turn unloaded at 7400rpm on a 2s 7.4v pack and 11100rpm on a 3s 11.1v pack. Switching to a 3s pack will increase, not lower, the head speed and thus increase the load which means that the system draw more amps. Unless the original esc was seriously oversized to begin with, switching to a 3s pack without changing the motor and/or gearing is likely to smoke the esc, or motor, or battery or any combination of the 3. The only way to tell is to measure which is why tell the members of our club that if they are serously thinking of electric flight the one essential tool is a wattmeter!! D. |
May 17, 2011, 10:06 AM
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ScooterInVegas | |
ScooterInVegas Village Idiot! | Quote: Originally Posted by Dave Lindsey "Run time is dependent on mAh rating and amps pulled. Yes, you would have lower head speed. " Whoa, something's not right here. Switching to a 3s pack will increase, not lower, the head speed and thus increase the load which means that the system draw more amps. I miss read his 2nd sentence. I thought he was talking about going from a 3 cell to a 2 cell. |
May 17, 2011, 11:49 AM
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Mitchie | |
Mitchie Registered User Thread OP | Guess I'll just stick to the 3s in it. I don't want to have to buy 2s batteries. |
