I'm running a Speed480 direct drive with a folding 6x3. I've tried it with a 8x1700mah set and also a 7X720 mah set, I ran the static motor with both packs and before the TX throttle reaches the top it shuts, off the motor and signals an overload. I don't understand how this can be. The motor specs say it runs at 16 amps,I haven't got a meter I can put on it, but the safety isn't supposed to kick in until twice the rated capacity. I pulled it out of that plane and put it in a Wattage Tangent which was rated for a 15A ESC, and the same thing happened it died around 85% of the throttle. I'm new to electronics and will have a meter soon, but I thought I'd ask just in case I overlooked something simple.

It is either shutting off the controller due to high Amps or it is shutting off due to Low Voltage Cutoff (LVC) circuit kicking in. By the size of the battery you mentioned (720mAH) I'd assume it is a AAA NiMH type cell. These can only handle current draw of up to about 5Amps. Above that the voltage will drop off rapidly and your LVC will cut in.

Tell me precisely the battery cell types and the motor model number (there are several variations of speed480). Then I'll run the numbers in Motocalc and tell you what's the problem.

The motor is a Graupner Speed480 7.2v and the 720mah are of the aaa size. The 1700mah pack is one I fashioned out of the new Enerigizer aa size NiMH, but I'm not sure about their reliability. I don't think they can handle the high amp draw like the one specialized for r/c flight. Can you suggest a cell that will handle up to 15A, in the 800-1100 mah range? Thanks.

GeraldO is right, the AAA NIMH batteries will not handle a Speed480. As soon as the motor comes on the output of the battery pack will drop below 5V and the ESC will just shut it back off. Try some HE1100 NIMH cells http://www.aircraft-world.com , they will work well. Also AA NIMH cells will work fine, http://www.nimhbattery.com/mh-dba-1700tab.htm but are a bit heavier.

Neither pack of batteries you've tried will handle a Speed 480.

AA NiMH cells, especially the ones you buy at WalMart, are meant to run low-current items like toys and digital cameras. They cannot handle 10+ Amps.

mkirsch, I beg to differ. The newer AA's are designed for quick charging, which means they can handle higher discharge rates. I use several brands of AA NIMH batteries (including Eveready 1700's) with a Mega 16/15/3 drawing about 20 Amps. You can drain em in about 4 minutes and still grab the pack without burning yourself. I have over 50 flights on 4 packs with no bad cells.