Max current draw for a 380 or 400?

[flying pro]

As I have changed prop size and pitch I have found that it is easy to melt these small electric DC motors. Is there a rule of thumb or a chart to find out what the Max current draw is for different motors? I would like the DC motor to last a min of 100 flights. but it does not have to last 500. I understand the more I push it the less flights I will get out of it.

[wattsup_kz]

The rule of thumb I use is, if it heats up enough to make it uncomfortable to touch, then you need to prop down or gear down. My speed 400s do not like more than 10 amps on 8 cells.

Brian

[flying pro]

Thanks that would make sense, because some motors might have different windings and therefor be able to take higher amps without heating up.

[portablevcb]

They will also act differently on different batteries. I keep my 7.2V sp400 to under 9A on 3sLiPo (yes a 6v sp400 is different than a 7.2V or 4V). The last one I set up was good for over 100 flights, but, those were at half throttle most of the time (3A). Cooling is very important if you are going to push the motors at 3/4 to full throttle during most of a flight.

If you can't hold your finger on the motor after a flight it is being pushed hard.

For these motors you can measure current using one of the cheap voltmeters that have a current measurement setting. They will usually measure up to 10A.

Make sure you break in the motors to get the best life from them.

The sp300 motors are probably the worst buy in the industry. They fly best with a lot of current, but, over 5A and they won't last long. Teeny little brushes in those things. Carry spares!

charlie