Bec

[j.m.]

I want to make my own BEC for my 8 cell rigger, and I have a few voltage regs I got from radio smack. They are rated for 1A max current. Would one of these be enough for a standard size digital servo?

[Ron W3FJW]

Yep. 7805s ??

[shanghai_fool]

You need to be careful about the input voltage also. 7805 max input is 35V. Also dropping 24.6 (8 cells) volts at 1 Amp is 24.6 Watts. Too much for that case type.

[j.m.]

8 cells Nimh. Yes, it's a 7805. So would a single digital full size servo ever draw more than one amp?

[Ron W3FJW]

9.6v, depends on the size. A servo used for quarter scale would probably draw about .7 or .8 amps or maybe more under a load, but the general run of the mill standard servos, IIRC, draw .4 to .6 amps. Your power dissipation in the regulator would be about 4.6 watts at most and would probably average around half that. What is a rigger anyway. Sorta shootin in the dark here.

[rmteo]

An electric version of this?
http://www.bbyracing.com/gallery/skipgreen3.jpg

[Ron W3FJW]

Looks like it would be ok.

[vintage1]

Stick it on an aluminium or copper plate though. Or a custom finned heatsink. The 7805 pack itself wont do much more than a watt in free air. That's about 0.25A continuous on a 9v nominal input.

[Ron W3FJW]

Thanks. Forgot to mention the heatsinking. One possibility would be to bond it to the metal ESC water cooler with a heat conductive glue or clamp it to the ESC cooler using a heat conductive compound. You do have a water cooled ESC don't you?

[j.m.]

Yes, I do.

But I have a different idea...

Pics as soon as it's done. (in about 10 minutes.)

[j.m.]

Here's my design:

[Ron W3FJW]

That looks good, but how do you cool it (ESC), or don't you. Looked at the boat from the link you posted & followed it down to the boat description & it didn't give any info on powering it (boat) or size. Just the kit details.