Is there a telemetry connection that can hook up to the balance adapter on my batteries from the rx to display voltage on my dx3s?

The 3300t will display total voltage at the RX. Several of us set the low voltage alarm for a model at 6.2v so it will sound when the lipo is getting low. Keep in mind it will only get you total voltage of the battery.

But that is for nitro right? Cause electric does not have a separate rx batt. Mine is blank on my radio.

Unless you are running an external bec or rx battery pack the voltage indicated on the screen will the the bec output voltage from your esc (it will not change regardless of battery pack voltage)

Spektrum sell a separate telemetry module setup that will monitor pack voltage, it requires additional sensors and wiring

Link below will run you through it

http://www.spektrumrc.com/Articles/A...ArticleID=1882


Cheers