Home Built UBEC - RC-Monster Forums

sikeston34m · **Home Built UBEC -** 12.04.2007, 07:29 PM

Would it be possible to take several of this style regulator and build a home made UBEC?

http://www.radioshack.com/product/in...entPage=search

They are good to 35v so they would work with up to 8 Series Lipo.

Maybe mount 3 to 5 of them to a heatsink and install a Cap on the output side to control noise?

Any thoughts?

MetalMan · 12.04.2007, 07:35 PM

You can make a BEC out of them, but not a UBEC. UBECs are switching regulators, the 7805 regulators are linear. That means that they burn off the voltage difference between your battery's voltage and the 5v the 7805 puts out. This will result in a decrease in runtime, compared to a normal UBEC.

sikeston34m · 12.04.2007, 07:38 PM

Aaaah, OK.

I'm thinking that how much they "burn off" would depend on how many you use and how much amperage you request of them?

For example, If I need to pull 1.5 amps to steer, then using 4 of them parallel might be a good idea?

MetalMan · 12.04.2007, 07:56 PM

It depends. If you are running 15v, at 1.5amps they would be burning off (15v-5v) * 1.5amps = 15watts. If my memory serves me correctly, you shouldn't try to get more than 5watts of heat out of each one. This is why you shouldn't use ESCs' internal BECs, because they are linear regulators that do this.

BrianG · 12.04.2007, 08:13 PM

And you generally don't parallel regulators, but use a higher power/current pass transistor. But no matter how it's done, a linear regulator is inefficient, especially as the supply voltage and load current increases.

That said, a linear regulator works well in the 2s (maybe even 3s) or 6-8 NiMH cell range. Since the voltage is so low, efficiency is close to a switching UBEC.

sikeston34m · 12.05.2007, 01:26 AM

I decided to go with Castle Creation's BEC Switching Regulator on my E Revo.

It looks like a pretty good setup. On 4S Lipo, it should help to take heat/load off the ESC even after I install the 125 Amp Monster Pro.

http://www.castlecreations.com/products/cc_bec.html

Anyone had any experience with this one?

I know JohnRob did a pretty impressive video with it.

MetalMan · 12.05.2007, 01:29 AM

I think a lot of us use it. I have three of them, but am only using two right now. One on 3s, the other on 4s, each with an Airtronics 359 servo, and set at 6.3v. They've been working flawlessly.