I just got a brand new Airtronics MT-4 transmitter, and installed a set of Eneloop AA batteries. The batteries fit very tightly in the battery holder. The battery holder has a connector that I can plug into my MRC superbrain charger. My question is: what charge rate can I use? The eneloop batteries are 1.2 volt, 2500 MaH. I would prefer to remove the battery holder with batteries installed and charge this way, as the batteries pretty difficult to remove from the holder. Thanks

AA batteries are generally charged at 1/2 C , So 1.25 amps.

Unless you are in a huge hurry to charge the radio the I'd only charge at .5 amps. I'd also highly suggest you remove the battery cover when charging, this will allow you to keep the cells at their coolest during charging and also let you monitor temp by feel or use of a temp gun. The lower the charge rate, the higher capacity the cells will charge up to and promote the longest cell service life.

Thanks alot

4.8V fully charged is on the low side for a Tx IMO....me and some of the Spektrum guys bought NIZN rechargeables from HK (1.6V nominal) and fully charged, they start at 7.1V!

With 5 batteries, charger and shipping to my door was $18...probably cheaper for you since you're in the U.S.

I suspect many if not most modern computer type transmitters have voltage regulators built in to protect the relatively delicate integrated circuit chips they are based on. I know the earlier Spektrum transmitters do. Doubt if higher voltage batteries above the minimum required provide much benefit, as the regulator knocks them down to a proper level for the circuit board anyway. I've not seen much if any difference in performance or range from mid 6V to mid 4V with a couple of 4AA radios.

Over most of the useful discharge curve 1.2V nominal rated nickel based rechargeables aren't much different than 1.5V rated alkalines for voltage, other than the alkies do start a little higher.