a little confused
07-18-2010, 08:09 PM
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a little confused
I just had to change the motors out in my GWS f-15 and decided to upgrade them from the stock 3600kv in runners to some 5000kv out runners. I'm guessing the speed controllers that came with the plane are the stock GWS 10-15a each. The battery I flew with today is a turnigy 2600mah 3s 20-30C.
With the new motors in the plane it flew for about 3mins versus the usual 4 and the battery swelled up preety fat! This is because of the new motors drawing too much amps? Why would the new motors cause the battery to suddenly swell?
Can someone explain the ratios of C ratings from battery all the way through esc to motors for me?
With the new motors in the plane it flew for about 3mins versus the usual 4 and the battery swelled up preety fat! This is because of the new motors drawing too much amps? Why would the new motors cause the battery to suddenly swell?
Can someone explain the ratios of C ratings from battery all the way through esc to motors for me?
07-18-2010, 08:25 PM
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RE: a little confused
Dude if you increase the motors rpm per volt by 1400 then obviously the fan is going to be spinning faster and the motors are going to draw a LOT more current to spin at this higher speed.
5000Kv is a little too high for GWS fans, 4400 would be a safer limit on 3 cells, you will likely burn up the motors from repeated running with 5000Kv and I imagine you will be pulling 30A at least, which means a 60A load on a battery rated to a maximum continuous of 52A (and turnigy ratings are to be taken with a pinch of salt).
Surprising the ESC's didnt pop, the battery voltage would have sagged out badly which would have reduced the amp load a lot and likely what saved the motors & esc's from frying. Didnt save the battery though, you would have killed it with this, swelling means you have deposited lithium onto the anode plate which causes oxygen production inside the cell, you will have lost a fair % in capacity too if the swelling was severe.
5000Kv is a little too high for GWS fans, 4400 would be a safer limit on 3 cells, you will likely burn up the motors from repeated running with 5000Kv and I imagine you will be pulling 30A at least, which means a 60A load on a battery rated to a maximum continuous of 52A (and turnigy ratings are to be taken with a pinch of salt).
Surprising the ESC's didnt pop, the battery voltage would have sagged out badly which would have reduced the amp load a lot and likely what saved the motors & esc's from frying. Didnt save the battery though, you would have killed it with this, swelling means you have deposited lithium onto the anode plate which causes oxygen production inside the cell, you will have lost a fair % in capacity too if the swelling was severe.
