DSX9 and lipo's

[Bond007]

Just a friendly word of warning

DO NOT USE A LIPO IN A DSX9 TX

If you do you'll fry it, and you'll foot the bill.

Sean

[3dbasher]

oh dear not a happy bunny then

[Smoothound]

Hmmmmm works fine in the PCM9X2. What have they changed?

[Bond007]

It hasn't happened to me fortunately.
I was chatting with Mr Macgregor at the weekend, on behalf of a friend who was using a FlightPower TX Lipo, in his DSX9.
Just thought I'd share the info.

Sean

[SRH990]

I'm another PCM9X2 user happily using a lipo pack.

[flatspins]

It does say in the instructions not to use a lipo.

I guess if it does go wrong, they will know it was over voltage due to lipo use, and your warranty will be void.

Probably never be an issue, but........
Is it worth the risk?

The 1500MAh NIMH that comes with it lasts ages anyway.

[SRH990]

Mines well out of warranty anyway. I'm using the Flightpower 1500mAh TX lipo pack which lasts much longer than the 2200nimh pack I was using before plus it stays charged, unless you use Enerloop cells nimhs self discharge rate is too high.

Ever wondered why power tool manufacturers are going from nicad cells which are soon to be banned direct to lithium ion, nimhs are useless for power tools because they don't like high output currents and they sekf discharge too fast.

[Sesame]

After reading this I had a quick look into it as at our field 90% of dx7 users are using Lipo's myself included, again mine out of warranty anyway, but I found this on the spectrum site

http://www.spektrumrc.com/Articles/HobbyWire.aspx

Heads Up, Use the right batteries in your Spektrum transmitter for best results
Monday, March 17, 2008

Warning concerning use of non-standard transmitter batteries
Spektrum transmitters are designed to be operated on 9.6 or 4.8 volt Ni-cad or NiMh batteries only. Use of Li-Po or other power devices operating at higher voltage can add heat to the system, possibly overloading the power regulating transistor for reduced output. Despite what aftermarket battery manufacturers might suggest, use of non-standard batteries offers decreased reliability of your Spektrum. Our service department has received failures associated with Li-Po packs.

what I was wondering from those with a far better understanding of electronics than myself, if you charge the lipo up not to peak but so that its showing 11V on the TX then what difference if any is there gonna be from using a NiMh as once charged it shows a value between 11 and 11.5V.

The problem the way I understand it is that the extra voltage of the lipo is overheating the components which is what would cause the failures, hence if you keep the voltage down does it follow that this overheating wont happen.

I like using the lipos easier to charge quicker to charge and lasts a darn sight longer, but now concerned that im gunna melt my dx7, even though been using it for the last 6 months without incident, blimey glad im not gonna be using it today LOL

[paddy]

probably because the Nimh battery wont stay at 11v, it will drop to around 10.6v in thie first few secs. Lipos will be happily hold 11v for ages causing the overload they're worrying about.
incidentally i damaged my JR PCM9X2 using a lipo in it, spoke to mcgregor and it was the reasoning spektrum are giving above.
I was under the impression there's no problem using lipos with spektrum.

[Sesame]

Lipos actually show 12.6V if you fully charge them and plug them in.

I cant find anywhere where spektrum actually quote the voltage range which they do on the Rx's.