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View Full Version : New to electric... will this be enough power?


warhawk40e
01-08-2007, 08:18 PM
Following the good advice I received here I now have a new GWS E-Starter. I used the motor that came with it, a EPS 400C. I bought an E-flight 20 amp ESC (not sure which one). To save money I want to use some existing battery’s that I already have. Those batteries are 8.4V 1000mAh Ni-MH. The instructions recommend using 7.2-8.4V AAA 500-730mAh NiMh batterys. Does this sound like a setup that will work or should I just go ahead and purchase the recommended battery's?

I just want to make sure this bird will have enough power for stable flight. Again, I am new and want to confirm that 1000mAH will give me just a bit more of a boost then what they recommend but not hurt anything? Am I correct in assuming the 1000mAh batteries are more powerful than the 500-730mAH yet will not cause any ill effects.

Thanks

dfalcon
01-08-2007, 09:16 PM
It won't give you 'more of a boost' to use the 1000mAh batteries; it will extend your run time. A 8.4V 500mAh battery will spin the prop at the same speed, but for half of the time (and also weigh about half as much as the 1000mAh battery). If it's the power your worried about try a 9.6V battery, or if you think you'll stick with the hobby for a while, invest in some Lithium-Polymer batteries and a compatible charger, as a 11.1V Lipo (3cell) would give you a definite increase in power and duration with less weight. You may have to use a slightly smaller propeller at higher voltages to prevent excessive wear on the motor. I'm sure there is a lot of information out there on people addressing these kinds of issues with the E-Starter if you have the time to search.

Solid Hit
01-08-2007, 10:07 PM
Just as a rule of thumb, I go for the most volts that are recommended. The volts will give you power but the amount of amps will give you run time. So 8.4 volts and 1k amps will give you more power and time in the air (even with the little extra weight) then 7.2 volts and 700 amps.

A 3s lipo (11.1 volts) will burn out your motor if you are not careful. The typical 400 brushed motor supplied with most kits is not equipped to handle that many volts. That being said, I do it anyway but I'm aware that I am shortening the life of my motor. When the motor does eventually die, I replace it with either a brushless setup and change the esc or with a cobalt motor that can handle the voltage and use the same esc.

The problem with the cobalt motors is the weight increase for the output received which is why I prefer to go brushless. (I just have a couple of cobalt motors handy).

spitace
01-09-2007, 04:11 AM
Somone made a sticky about this subject.
http://www.wattflyer.com/forums/showthread.php?t=1933
It looks like its got som great info so you should check it out.
Take a look,
Spit