i have a cc 35 amp esc and a four cell TP extreame lipo pack, how come i have to turn the BEC off to use a four cell pack and dose that mean i have to put in another battery pack for the reciver. this is going in my Lynx FX and i dont want the weight of two packs. thanks

That's CC's design, I think because they can't cut the 4 cell voltage down to what a reciever can use. so yes you have to turn it off and run a seperate BEC or a reciever battery, 4.8-6V...

just run a ubec or the cc bec. much less weight then adding a second batt. less maintenance too.

I agree, the esc creates a lot of heat when modulating the lipo voltage down to 5-6 volts need for flight pack. The more lipo cells you run the harder it has to work. I have been using the ubec on all my EDF from smaller to 3000 watt setups . No problems. The new Castle bec looks very good too. Much lighter than a battery. Doug

thanks to all for the help