I have an old Futaba RX without BEC. I connected an old cellphone batt and is working great. Its make the weight way less. Comments!!!!!!!

Most of the RX and servo equipment will work at 4.8v (or slightly higher like 5.1v), and a large part of them can handle up to 6v.  So any battery in that range should work. 

The question is duration (and discharge rates), which you will have to test and see for yourselves.

cellphone batts work great - servos are slightly slower

Obviously not to be used in larger aricraft with 4/5 standard
size servos.


Best to use with gliders and other small electrics without bec

I also use a standard cellphone charger to recharge - yeah - I know
not recommended - but  that's the way i do it

Cellphone "batteries" are usually single cell. They are 800mAh upwards, so current would not be an issue. However the voltage could well be borderline for receivers as I have said in my earlier post.

Proceed at your own risk!