RE: Two questions - battery/receiver
The story about the 3 wires for a center tap" is correct. Fourty years ago, in 1967, I had (still have) my first proportional set, a Galaxy 5, made by Ted White of pattern fame. It had seven wires on the servos, ("F&M Titan Magnevac") and three or 4 wires on the battery pack (seven button cells).
We've come a long way since then.
Today, the reason that batteries have three wires is because the radio and battery pack manufacturers use a SERVO LEAD for the battery pack lead. Since it already has three wires, the third wire (signal) isn't hooked up inside the battery pack. It is in there, and you will find it if you ever remove the shrink wrap from an old dead pack.
It is very simple; basic economics 101: If you take the third wire out, you have a very small additional labor cost. If you leave it in, it costs nothing. The labor is worth more than the third wire and terminal.
If you are a manufacturer of radio systems or battery packs and ordered two wire leads for the battery pack, you would need to order it as a seperate line item, recieve it, inspect it, stock it, isssue and kit it prior to assembly. Multiple part numbers equal more steps from the design stage all the way until it is assembled and inspected.
The retail price is generally arrived at based on a formula that includes the manufacturing cost plus a honest profit and a small fudge factor, and maybe other marketplace factors that I am unaware of.
Those costs are generally borne by the consumer.
The battery does not communicate with the receiver. It merely supplies the necessary opertional voltage to the receiver and servos.
Harley Condra
BVM REP
JetCat REP