I have a old kopropo helios. I want to convert its power source to 3s lipo. The problem I have is Helios has a low voltage alarm set at 9 v which is too low for 3s lipo. I think the minimum for 3s is 9.9v. So I need a some kind of cut off circuit between my transmitter and 3s lipo. Can someone direct me to a place that sells lipo cutoff circuit?
Thanks
Eddy

there is a voltage display on the screen... why do you need a lipo cutoff?

There is a low voltage alarm on Helios. That is set on 9v (i don't believe I can change that). If 3s lipo drops below certain voltage, it will have some damage. I believe minimum voltage for each cell in a 3s is little bit over 3. It would safer if I have that circuit. Or am I just being over cautious.

The minimum voltage is 3v/cell. You don't want to discharge mor ethan 80% of teh lipos capacity, so it will take a cutoff more like 3.4 - 3.5v/cell (10.2 - 10.5v for a 3S). You'll get better life from lipo if you don't always discahrge to the cutoff. Operating that way, you won't see very good longevity.


With the voltage on the screen, just re-charge when you see it get to 10.5v. I run a 3S 3300mah lipo in my 3PK and the voltage comes down pretty slowly, its not going to suddenly drop below min voltage in the middle of a race or something like that. You'll have plenty of time because of the voltage info on the sreen.


You're being overly cautious.....

thanks.
Maybe I will do a two 3s in parallel then I won't have to charge often.
I do agree that I am too cautious, that's what happen when I over analyzing on things I allready analyazed.