I understand that servo programmer is using it's own battery to power the servo during the S-TEST. However when I start testing my servos the internal battery will be good for no more than 2 hours of no load test (and probably less then 1 hour on load test). That means I will need to recharge the programmer a couple times before I test all my servos.

So here is the question: can I connect 4 or 5 cells external battery (I have 3800mAh NiMh) to the charging (Rx) plug to power the servos during the test?

RysiuM

Rich

It will NOT work, GOOD question though. When you turn ON the programmer the charge circuit is in-operative or isolated.

Since the battery is new, it will benefit from a few charge/discharge regimens.

So the other option (I think it should work) is to power the servo from separate battery. I mean to make a kind of Wye connector that would connect yellw and balck to the programmer, red and black to the external battery and yellow, red and black to the servo.

I love that

RysiuM

I believe that should work. As long as you share the common its all good.

The Y works fine with a 4.8V battery in parallel, that is what I have done in the past.

I have a 4000mAh lithium Ion and 6V regulator setup I am working on. I really want to be able to run them in at the voltage I am flying with.

I have a harness made up where I cut the + lead on the Y between the programmer and servo, and all 3 wires on the other side of the Y go to the servo under test and to the 6V battery. Basically only signal and common are connected to the servo from the programmer and 100% of the servo load is drawn from the 6V external battery. In addition to powering the servos at the flight voltage, the programmer gets 100% of the internal battery current so it lasts a lot longer.

I have used this approach on receivers to isolate power systems so I am pretty it will work on the programmer. Just need the time to test it out!

DP

I'll do that. My 3800 mAh pack is made of 5 cells NiMh so it is the right solution for it. This 10oz heavy sucker was in the plane before I swapped it for 5oz Lipo.

RysiuM

Am I getting the gist out of this thread that it is ok to power the programmer with a 6volt source?

Jim - NO, you definitely do not want to power the programmer with 6V, you will probably smoke it and void the warranty.

You need to modify a Y-harness. The drawing below clarifies it. you will cut the + line between the programmer and servo, and leave it unconnected. You will then splice the + and - into the lead that goes into the servo.

The programmer will then share signal and ground with the servo and only common with the battery so there will be zero chance of 6V getting to the programmer. The signal voltage is a standard that does not vary with voltage so there is no issue of powering the servo with one voltage and the programmer with another.

DP