Boy that's going way back...

I think that there was a way that they where able to change the battery voltage settings thru the GSU so that you could use lipo's with that ECU.

I would suggest that you get in touch with John Redman from JetCat and see if there is.

You should be able to change the voltage to lipo if you go into the limits page on your GSU. There will be a page to change from Nicad 7.2 volt to Lipo 7.4 volt. Then you will only be able to use a 2s 3300 mha lipo battery.