Hi Danno,
I don't understand that. Where does this 3.3v+ on the signal wire come from? The Rx is switched off for charging I expect, and since it is the Rx that produces this signal for the servo....? Am I missing something?
[/quote]
Hi John:

Andy at ED as well as CellPro and others do make adapter cables that convert the CellPro funky plug to a standard JR plug with 22ga wire. That way you can make up any extension you need on your charger and batts with standard servo wire. The yellow or orange signal wire carries the 3.3v center tap of an A-123 2-cell pack to the JR charging jack on the switch, or directly to your female JR plug on the charger for balanced charging.

The switch does carry thru the signal wire to the RX........basically same switch used for DSC, which has become almost obsolete here in the U.S. with the changeover to 2.4.

This setup with JR 3-wire and plug is limited to a 2 cell pack, since 3 or more cell packs require 2, 3 or more taps, thus requiring plugs with more than 3 contacts.

I don't use JR wire or mechanical switches on my bigger birds, only 2-wire (16ga with EC-3) with soft switches, so I don't have that signal wire going all the way to the RX, but I still can't simultaneouly charge 2 packs with my 10S, unless I put the battery backer in line which breaks the negative line. While the 1222 and 9100 do isolate the batts internally according to JR, they still appear to have a diode or some other internal device in the RX that only isolates the + side.

Gonna pull out the volt/ohm meter and do some checking to verify.

So much of this is moot, since A-123 can be re-charged so fast at the field. Who needs simulataneous charging anyway?

Hi Tom,
Thanks for the explanation. That makes sense now. I completely agree with you BTW, why do you need to charge both batteries at the same time? Patience is a virtue.