Problems with Li-po / Li-Ion Batteries in DX7??

[Blue Note]

Just wanting to get up to date regarding the use of the Li-Po or Li-Ion batteries as a replacement battery for the DX7. I don't really care about having to charge the night before going flying, but I have read about people using the lithium batteries in the transmitters. I have also since read about people having problems due to running the higher current. What are your experiences and solutions for these issues? I definitely don't want to screw up a new system by choosing the wrong battery, but the original battery is toast.

[Anson]

I've been running the stock Align pack that came with my trex 450 V2 for awhile now with no problems at all.

what problems have you heard about with higher currents?

[Blue Note]

The generic 'problem' that I've heard about is that the higher voltage will 'burn up' some of the components in the Tx. Evidently, Spektrum has not publicized the voltage range tolerances, or they are hard to find. If the radio is designed to run on a 9.6V NiMh that peak at about 11.2V and you just put in a 11.1V Li battery that will probably push about 12.8V, you may be overdriving the components and eventually cause failures. I read about this more in the JR systems, but cannot confirm. So far, the best solution I've found if you want to run say a 2000mAh Li-ion, may be to put a diode or two in line between the battery and the Tx. I was wondering about other peoples knowledge and experience with this. I've started down this path since my original TX battery was bad out of the box and they do not seem to hold up as well as other brands. Your mileage may vary.

[Pinecone]

The DX6 at least, used a linear voltage regualtor to provide 3.3V to the actual transmit module. Higher voltage could cause this to overheat.

Not sure what the SX7 or JR do with this. Best solution would be to put a small swithcing regualtor in line to provide the proper voltage to the Tx. Of course to do this RIGHT, you would need to run the meter off the unregulated pack. :)

You could use a pair of these: http://www.dimensionengineering.com/DE-SWADJ.htm

[Rodney]

I have a 2000mah 3s2p Infina-Ion pack in mine. It has been running the transmitter for over 80 hours of use with no issues of radio failure at all. No glitches or radio signal problems. The only thing I have learned while doing this is that you can not charge thru the transmitter port at a rate any higher than 1 amp. But that goes for the stock pack as well. The fuse will not take the higher charge amps and it pops.
There are about 125 or so of these packs by formerly known as Rodney Corp, now is Infina Models in use.
They are in JR/Spectrum DX7, 9303 and 9303 2.4,10x. And radios with XPS systems and Spectrum conversion modules as well as Futaba 6ex,7c,9c,9Z and even Airtronics.
There has not been one report of radio failure, or battery failure except the ones that have been left on for days at a time.