what kind and where can i get lipo batteries for my jr 8103 radio recever. i am also looking for lipos for the wren 54 mkIII. THANKS FOR THE HELP

Hi Chipperg,
I am just considering the same question myself. Currently I am using Thunder Power batteries mainly and laterly I have fitted a 2s2p 4000 battery to my Jetcat P120 with excellent results. I am just about to do the same for the Wren 54 Mk 3, but there is one small problem. I have been advised by Wren and by others using their engine that the system gives better throttle response on 5 volts whereas with a 2s Lipo you would be running at a nomonal 7.2 volts; too much. A 1s Lipo is not enough.
So I am going to build a regulator this week that will be adjustable and there fore suitable for the mark 3 and the Supersport. I believe that in the USA there are sources of regulators for this purpose already available. I am sure there are pilots already using Lipo's on your side of the pond who could give you directions to the best source for your needs.
Regards,

John.

Hi John ,

Don't worry about the voltage being too high. The FADEC just uses less of the pulse width range . I've been using a 2s pack on my MW44 and it works fine . In fact , Wren is now offering an autostart version of the MW 44 that uses an 8 cell Nimh pack . It has not caused throttling issues.

Marc

Hi Marc and Chipperg.
I take back what I said. I have just read a PM from Garspar Espiell saying the same as you. I have to say I was a little suprised when I was told that the FADEC could not handle the extra voltage, and now the man himself has spoken; good enough for me.
Regards,

John.

Hello John

If you want to make one I used the National Semiconductor LM1048 adjustable regulator. It is good for 5A and with a good heat sink I have used it on my mw 54 with Eco fadec on it. I ordered it from www.digi-key.com. Im working on trying to make a parallel one for 10A but I’m still learning circuit design and electronics. [sm=drowning.gif]

If Gaspar says it can handle then it must be good to go.

Gaspar just a few questions and you can PM me if you want.

1. How may steps does the ECU use to control the turbine.

2. Do your different ECU's have different amounts of pump steps for throttle control.

3. What is the acceptable top % of pump steps for full throttle for smooth control of the turbine?

Thank you for making a great ECU Gaspar! im converting my old RAM 750 to Fadec next.

I tried a 7.4 volt lipo on my Wren 54 MK11, in place of the 4.8 volt nicad.
I just about lost my plane. When it ramped up, flames shot out the rear of the turbine & fried the elevator stabiliser on my Tango. It looked like the pump was delivering too much fuel.
If it is possible to use a lipo then I think changes must have to be made to the ECU settings.
Any suggestions as to a solution are welcome.
I have repaired the damage & gone back to my nicad.

Regards