Originally Posted by healthyfatboy
This may be a little off topic but since we fly gliders here, I figured it was worth mentioning.
I use a Futaba 9C for my planes and FPV truck and the stock battery has always not held up very well. I'll do a lost of ground testing to make sure everything is working properly and then once I get to the field, I have to cut things short because the battery is always going flat on me in the transmitter.
I know lots of people have used 3S LiPo batteries in their transmitters with a couple of diodes to drop the voltage to make sure it doesn't damage the transmitter but I found that using a LiFe battery takes care of the problem because of the slightly lower nominal voltage.
I used to use an All-e-RC LiFe battery but I found 2DogRC's 2500mAh battery to be a better fit for my transmitter. It was 400mAh larger in capacity and the version I got has the plug for Futaba and JR so if I decide to ever get another Spektrum radio for small BNF stuff, I can use the battery in either. The All-e-RC one was a pain as the proper connectors weren't on it at the time I bought it so it required a little bit of modification to work.
I only have to charge my transmitter battery once a month or so with this upgrade so it has definitely been worth it for me. It holds a nice, steady voltage at 9.9V so it's right where it needs to be on my 9C.
Sorry again for the OT post but I just thought I would pass the information along to anyone that may use a Futaba or JR/Spektrum radio as I hardly have to charge my transmitter now! Definitely worth the LiFe battery.
Yes, I'm bored. My plane is ready for it's maiden now that I have swapped out the stock RTF servos for HXT900's and it's been raining for three days now. I guess I can't complain with the 60 degree temperatures though!
I'll second the recommendation for a LiFePO4 tx battery.
I've used a 3S LiPo in my Futaba 8U for a couple of years (without any diodes or resistors) and have had no issues. However, when HK came out with an appropriate sized LiFe pack this spring I sprung for one for the same reasons you stated. Been flying it for a couple of months now without having to recharge it and the voltage indicated on the tx has dropped from 10.1 to 9.4. The 9.0v low battery alarm of the tx will be just right for LiFe battery charge time as well.
I did have to replace the connector to fit my radio, but that is an easy task especially if you have a crimping tool and servo pins and housing. I also had to remove the bottom-side foam cushion in the battery compartment as it's a snug fit. Me happy.