Hey guys. I recently bought a Caldera 10e with a 540 brushless. When I bought it the guy had 11.1 volt LiPO batteries for it. Now I'm new to this hobby but I do understand the difference between AC and DC motors. Shortly after that I burned out the ESC and put a 180 amp ESC in it and it runs fine now other than chewing up gears. I also just bought a volcano epx. This one has a brushed motor. I also have a Wheely King. Now the wheelie King I've just put a brushless motor into. My question is is it a normal thing for people to use 11.1 volts to up the speed. The Caldera screams! The volcano is okay. And I'll probably upgrade that to brushless motors in the future. But on the sheet for the volcano which I bought new it says the electronics are designed only for 7.2 or 7.4 LiPO batteries. So with brushless motors I can't see any harm with going to 11.1 because your varying the frequency rather than the voltage. Obviously that could cause a problem with a brushed motor. But is it common practice to up to speed by using a higher voltage battery? I mean if I went and put an 11.1 volt in the wheelie King with the brushless motor is it going to pump up the speed? And yes I do understand the ramifications of heat in these particular instances. I bought the Caldera used so I really didn't know anything about the voltages for the batteries on these things. Thanks for your help.
Trucks 11.1 Volt Vs 7.4 Volt
- Thread starter Tommy
- Start date
Tony
Staff member
You need to follow what the manufacturer states for a given motor and ESC. If it says 7.4 only, then do not put a 3s lipo on it, you will burn it up. Yes, brushless is a 3 phase motor that switches the phases on and off, but it still carries the voltage and current. Too much voltage and the motor will over speed which will destroy it and too much current and you will burn the windings which will also destroy the motor. Go with what the company states.
Thanks Tony, my problem is I don't see a whole lot of information on what the manufacturer States except for the new one. The one I bought used obviously I don't have any specs on that. And the brushless that I just put in the wheelie King it didn't have any specs either but I assume I can find those online. I see the difference between 7.4 volt and 11.1 volt lipo is the difference between 2 cell and 3 cell respectivly but it seems like the bigger or better rather ESCs automatically detect whether it's a 2 or 3 cell, so they compensate for that? I mean if the ESC gives you 2 beeps to tell you it's 2 cell and three beeps if it detects a three-cell wouldn't it be okay to use a 3-cell?
Tony
Staff member
Absolutely not. It is just letting you know that the battery you have connected is a 2 or 3 cell. If you put a two cell on and you only get two beeps, then you know you have a dead cell in the pack. Of course your charger would find this before your ESC, but still, it is just an indication of what was plugged in. It in no way regulates the voltage that goes to the motor other than on a scale of 0 to 100% when you apply or reduce throttle.
I would assume your next question would be "what if I put a 3s on a 2s motor and I just didn't go over 66.5% on the throttle curve". And the answer to that is when it is powering up, especially using a governor, it will still use the full 3s voltage to get it up to speed and then regulate it to what you have your throttle set to.
It is a risk I would not take.
I would assume your next question would be "what if I put a 3s on a 2s motor and I just didn't go over 66.5% on the throttle curve". And the answer to that is when it is powering up, especially using a governor, it will still use the full 3s voltage to get it up to speed and then regulate it to what you have your throttle set to.
It is a risk I would not take.
Thanks again for the help. So I'm going to leave it as is, however I was going to put the same I think they're called Dano plug on the wheelie King with the new motor. Instead I'm going to go with the banana type connectors so that there's no way my ten-year-old can get that 11.1 volt battery into the other two trucks. I have to have a moment of wisdom.
Smoggie
Well-Known Member
FWIW changing batteries does not in any way change the 'frequency' of the motor.. It changes the voltage and that in turn changes the current.
On a plane if you put in an 11.1V battery where there used to be a 7.4v battery then the current (amps) would roughly double. It would be very unlikely that the motor would be able to cope with that increase in current and power and it would probably burn out.
On a plane if you put in an 11.1V battery where there used to be a 7.4v battery then the current (amps) would roughly double. It would be very unlikely that the motor would be able to cope with that increase in current and power and it would probably burn out.