Raven power down during flight?

[CarVac]

I thought he was discussing the shorting of the outputs of an altimeter for shipping a misbehaving altimeter back to the manufacturer.

Instead of shorting the output and accidently destroying the FET, I was suggesting using a 10 ohm resistor which would effectively short the outputs but not damage the FET if accidently fired, nor would it excessively heat up.

Bob

What I meant was to make a short to bypass the current-limiting circuitry in the battery.

I hadn't yet seen the tutorial from the Altus Metrum guys which shows it as completely removing the limiting circuitry, so I was conjecturing as to how to perform the operation.

 

[keithp]

I hadn't yet seen the tutorial from the Altus Metrum guys which shows it as completely removing the limiting circuitry, so I was conjecturing as to how to perform the operation.

Yup, we completely remove the current limiter board from the battery -- that's because the altimeter has built-in current limiting, so you don't need the board in the battery. When we first analysed the batteries, the current limiter boards worked fine with our pyro circuit, which fires for only 50ms, so we figured having the extra protection in case you shorted the battery leads somehow (like dragging the bare board across a metal surface) was a nice thing. With the newer boards, that's no longer true, but the battery is still protected by the flight computer from over charge or over discharge.

 

[Adrian A]

On this same topic, will the batteries go dead in a power perch after a flight (if the altimeter is not turned off). For example, the rocket was stuck in a tree and could not be recovered for a few days. I ask because this happened to me and now, that battery will not take a charge. I know LiPo's are not supposed to drop below a certain voltage. Does the Perch have a voltage cut off/shut down/battery protection?

The cost of a 9V is higher than the small LiPo, so If they are damaged in a flight, i still don't mind. I was just wondering if that what happened to that battery.

-Jason

The Power Perch does not have a battery cut-off. When it's powered off, it drains the battery around 1% per day.