Maybe a dumb BEC question

[Turbojoe]

I keep wondering about this. Why carry the extra weight of a battery for an external BEC? Why not pull power for the BEC from the flight pack? If flight pack voltage drops below safe voltage to power the radio then it's a pretty good bet there's not enough power for the motor to keep the bird in the air anymore. No chance of a crash at that point. Maybe I'm missing something but the extra pack just seems like dead weight to me.

I have the stock GAUI BEC along with this: http://www.medusaproducts.com/BECs/MR-BEC-45035.htm I have the 45035-6 6 volt version. I bought the Medusa for an airplane that was planned for 4S but I ended up staying with 3S so didn't need external BEC. Now it's available for the heli if I need it.

I see Castle Creations is coming out with a 10A BEC soon!

Joe

[Sunkan]

If I had a BEC that handled 6S I would use that instead of a separate 2S pack together with the Gaui BEC. But since I don't have that I'm using a separate pack which is just one more battery to keep charged :(

[Finless]

You can get BEC's that will support up to 12S input.

somethiong like this would work
http://www.readyheli.com/35_Volt_Ultimate_BEC_p/ubec35.htm

I plan to go that route at some point.

Bob

[Turbojoe]

Thanks guys. So I guess the Gaui BEC just can't handle the high input voltage. (I haven't been able to find any specs on it.) For the ridiculously low price of a good high voltage BEC the low volt BEC and a battery pack seems like a stone age solution to the issue. The extra weight of the battery and the chance it could go dead in flight just don't make any sense to me. I'll be using the Medusa BEC then. It supports up to 45 volts input so I should be in very good shape with it.

Joe

[Turbojoe]

I've got the Align 5.1 volt step down adapter. Is it best to put it between the RX and the gyro and have both operate on 5 volts or between the gyro and the servo and have the gyro work on 6 volts and the servo on 5 volts?

Joe

[Raydee]

I don't think you need it between the gyro and the reciever. Its the Futaba servo that needs to run at 4.8 volts so the step down should go beteen the servo and the gyro.

as far as BEC goes I ordered the Western Robotics Hercules BEC for my 550 that is good for up to 11s. I was going to use a seperate battery but I decided that since I may go the A123 route for cells that I need to save as much weight as possible.