Switching BEC from a car charger

[jetstream]

Anyone tried using a car phone charger as a BEC.The one I have uses a MC34063 switching chip and output is about 5+ volts.Thing is that its meant for a nokia phone and there are 3 wires out.Anyone can shed some light on these.
Tried hooking up to a rx and 3servos. Works but some glitching from the servos.Would a filter help or am I barking up a wrong tree. Thanks

[Dan Baldwin]

The car chargers that I have played with that are based on the MC34063 are limited to very low currents, so I wouldn't try to use them on a plane. You might be able to change the current sense resistor on the primary and get more current out.

Dan

[jetstream]

Thanks Dan.Read the specs on the 34063 and it says it can handle 1.5amps and more if there is an output device so that sparked my interest and the chargers were going for $3/- a piece.
Dan,why not design a switching BEC for us mere mortals? It should be easy peasy for you!

[Dan Baldwin]

The 34063 is capable of handling plenty of current for a switching BEC, but it has built in current limiting, and the charger MFGs use it to make sure that the charge rate isn't too high. I think I could only get about 500 MA out of the charger I played with at about 5 volts.

Yup, shouldn't be too tough to come up with a switching BEC using a 34063. I don't think any real design work would be necessary, just build it as shown in the data sheet. The only design work would be part selection. I'll take a look at it.

Dan

[jetstream]

My planes and I humbly await the Master.