Why spektrum rx batt has 3 wires?
10-09-2007, 07:35 PM
#1
Thread Starter
Why spektrum rx batt has 3 wires?
My new Spektrum DX7 has a flat nicad rx battery pack with THREE wires coming from it. It doesn't fit in my plane's battery box and I am thinking of getting a SQUARE pack, which would fit. Most square packs just have two wires though....
What is different about the Spektrum system that might need three wires?
What is different about the Spektrum system that might need three wires?
10-09-2007, 08:18 PM
#3
RE: Why spektrum rx batt has 3 wires?
A lot of battery packs have 3 wires but not really needed for our applications. It center-taps between the second and third cells in a 4 cell pack. Don't worry about if it is there or not.
10-09-2007, 08:26 PM
#4
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RE: Why spektrum rx batt has 3 wires?
You don't need a 3 wire lead to the battery pack, but you do need a 3 wire SWITCH HARNESS with the Spektrum. This is because the bind plug needs to be able to ground the signal lead on the battery input.
Spektrum sets come with a 3 wire switch, however if you don't have one (eg changing out a plane to a Spektrum Rx) one solution is to plug a Y harness into the Rx battery input. Connect one leg of the Y to the 2 wire switch lead and use the second leg to insert the bind plug.
Regards
Terry
Spektrum sets come with a 3 wire switch, however if you don't have one (eg changing out a plane to a Spektrum Rx) one solution is to plug a Y harness into the Rx battery input. Connect one leg of the Y to the 2 wire switch lead and use the second leg to insert the bind plug.
Regards
Terry
10-10-2007, 09:34 AM
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RE: Why spektrum rx batt has 3 wires?
The third wire, if present on a receiver battery pack for RC use is not connected and under no circumstance would be connected as a center tap connection, as that would put voltage on the signal output of the receiver (if you have a three wire harness) when the receiver shares the last channel with the designated battery input (very common).
Three wire switch harnesses are also used for the DSC function (direct servo control), all of my switch harnesses are three wire (MPI heavy duty).
I think that it probably is cheaper from a manufacturing point of view to use a standard three wire servo plug on a battery, as these are produced in larger numbers than ones produced for use on batteries.
Pete
Three wire switch harnesses are also used for the DSC function (direct servo control), all of my switch harnesses are three wire (MPI heavy duty).
I think that it probably is cheaper from a manufacturing point of view to use a standard three wire servo plug on a battery, as these are produced in larger numbers than ones produced for use on batteries.
Pete
10-10-2007, 10:04 AM
#6
RE: Why spektrum rx batt has 3 wires?
Why spektrum rx batt has 3 wires?
Rafael
10-10-2007, 02:14 PM
#8
RE: Why spektrum rx batt has 3 wires?
ORIGINAL: pilotpete2
The third wire, if present on a receiver battery pack for RC use is not connected and under no circumstance would be connected as a center tap connection, as that would put voltage on the signal output of the receiver (if you have a three wire harness) when the receiver shares the last channel with the designated battery input (very common).
Three wire switch harnesses are also used for the DSC function (direct servo control), all of my switch harnesses are three wire (MPI heavy duty).
I think that it probably is cheaper from a manufacturing point of view to use a standard three wire servo plug on a battery, as these are produced in larger numbers than ones produced for use on batteries.
Pete
The third wire, if present on a receiver battery pack for RC use is not connected and under no circumstance would be connected as a center tap connection, as that would put voltage on the signal output of the receiver (if you have a three wire harness) when the receiver shares the last channel with the designated battery input (very common).
Three wire switch harnesses are also used for the DSC function (direct servo control), all of my switch harnesses are three wire (MPI heavy duty).
I think that it probably is cheaper from a manufacturing point of view to use a standard three wire servo plug on a battery, as these are produced in larger numbers than ones produced for use on batteries.
Pete
My A123 cell pack (two cells ), has a center tap which allows the charger to monitor and charge each cell for purposes of balancing.
Yeh-- I was surprised when I found the 3.5 volts from the center tap showed no effect. It was a brain far t initially and when I realized I had been flying it in that setup (on two different models ) I was mortified. But again - no effect.
