Spektrum DX-7 Transmitter
The old days of worrying about getting your remote controlled airplane shot down by another pilot’s radio because of crossed frequencies is long past. Now, 2.4 ghz digital transmitters allow safe and secure flying as far as your eye can see. Yes, I fly radio controlled planes. My radio is a Spektrum DX-7 transmitter which I have owned since about 2008. The last couple of years I have noticed that the battery charge depletes quickly when used. It is time for a new battery but I don’t know that I want to spend $30 for a NiMH (nickel–metal hydride) battery pack when I can get a lipo (lithium-ion polymer) battery that cost a little less and will hold a charge all summer rather than just a few flights!
So, I want to upgrade to a lipo but my radio isn’t designed to support this type of power source. The DX-7 comes with an internal voltage regulator that is not rated for more than 12 volts. The NiMH battery is 9.6 volts and a 3 cell lipo is 12.6 volts. I could only charge the lipo to 80% capacity putting it at about 11.1 volts but even so, there would be a possibility that I could over-charge the lipo past that 80% and fry my radio. I searched the web and found a solution!