7.4v Lipo for Rx/servos

[chris irvine]

I am assembling a Boomerang 40 sports trainer as a first plane model. I have been flying R/C helis for a while and have a collection of 7.4v Lipos. I want to use one of these for my on board systems.

I know I'll have to regulate the voltage down to 6v - I don't want to go lower than this as cell drain beyond 3v per cell can permanently damage the battery.

Am I employing sound thought process on this one? Seems to be a smart way to go as I have battery charging systems around every corner in my office.

I know most are using Enerloops or other suitable NiMH setups.

What sayeth thee?

Chris.

[Tim Mackey]

The regulated output will have no effect on the input voltage. The very design nature of the regualtor is that it will maintain a steady fixed voltage on the output side irrespective of the input voltage ( not withstanding the input must be at least as high or higher than the required output - most are switcheable between 5v or 6V.

Steps need to be taken to not let the Lipo drop below about 6V - and some devices have bult in monitoring to assist with this. In the models I have which do not feature this monitoring, I simply fully charge the battery before each use, and then again before the next use, I have flown certain models almost literally all day, and the Lipo has not dropped below around 6.5V. Of course, this duration is dependant on the capacity of the Lipos.

[chris irvine]

The Lipo I have in mind is a 1000Mah and rated at 16C. I'm thinking this should be fine. I am using an OS 55 AX with a 350Ml capacity tank which apparently gives around 10-12 minutes of flight time. I will check the voltage after the boomerangs maiden flight - this should give me something to measure the rate of battery drain.