I ordered from Towerhobbies a receiver battery pack for one of my airplanes, a HydriMax Ultra NiMH 750mAh, because I wanted a bit more assurance that it would not drain off as I was using one servo that was digital. To my surprise the pack is made up of 4 AAA cells not the usual AA size. I was wondering if this pack would drain quicker than say a 750mAH NiMh pack that was made up of AA cells, even though they are both 750 mAH?

Winglift,

As you've observed, NiMh batteries are smaller than NiCd batteries. As you go up to larger mAh batteries, the difference in sizes increases as well. For example, the last 2000 mAh NiCd battery I purchased use sub C cells and the same size NiMh battery uses AAA cells. Both batteries will work up to their rated capacities. I'm not trying to start a lengthy argument here, but FWIW I've quit using NiMh batteries all together. I've had a couple receiver packs fail in flight with disasterous results. I think they are OK for smaller sport planes, but I don't think they can stand up to the vibration of a gas motor in a larger plane.

I hope I answered your question.........

Bottom line, 750mah is 750 mah. Chemistry is irrelevent.

Now, the larger cells may have less internal resistance and therefore deliver more amps without dropping voltage but thats another question.

It states in bold letters that it is a AAA pack in the ad, http://www3.towerhobbies.com/cgi-bin...&I=LXPYL6&P=ML