Simple Bus-Tie Circuit using Schottky Diodes ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ http://www.rcgroups.com/forums/showthread.php?t=1854050 When using a separate Universal Battery Elimination Circuit (UBEC) to power your receiver and servos, the Electronic Speed Control (ESC) integrated BEC isn’t utilised. This simple bus-tie circuit allows you to connect the UBEC and the ESC’s integrated BEC so that in the event of the UBEC output voltage dropping below that of the ESC’s BEC, the ESC’s BEC will instantaneously take over. This provides a little extra peace of mind for little cost and only a few grams in weight. You will need one Schottky barrier rectifier. I got five MBR1545CT 15A 45V from eBay for about $3. You could also recycle one from a computer power supply or simply use two single schottky diodes. How it works video. http://www.youtube.com/watch?feature=player_embedded&v=gNjYF7vuAO0#! Header Pin Supply http://www.jaycar.com.au/productView.asp?ID=HM3426 When using a separate Universal Battery Elimination Circuit (UBEC) to power your receiver and servos, the Electronic Speed Control (ESC) integrated BEC isn’t utilised. This simple bus-tie circuit allows you to connect the UBEC and the ESC’s integrated BEC so that in the event of the UBEC output voltage dropping below that of the ESC’s BEC, the ESC’s BEC will instantaneously take over. This provides a little extra peace of mind for little cost and only a few grams in weight. This short ‘How to’ shows you what’s required, how to put it together and how it works. First, here is the schematic. Did I mention this was simple? Parts You will need one Schottky barrier rectifier. I got five MBR1545CT 15A 45V from eBay for about $3. You could also recycle one from a computer power supply or simply use two single schottky diodes. One 6 pin header board (I get mine from Jaycar in Australia) and one servo lead. You will also need some small heat shrink and some liquid insulating material. I used liquid tape (again from Jaycar). How to: 1. First bend the legs of your header and Schottky as per the photos. I also removed one of the pins from the header board, as only five are required. Remember the UBEC doesn’t have a signal wire. 2.Glue the schottky to the header. 3.Strip the insulation from the wires at the end of the servo lead that will connect to the bus-tie circuit. Tin these wires, then slide heat shrink over the wires before you solder them to your bus-tie. Then solder the header board, schottky and servo lead. 4.Slide the heat shrink over the solder joints and shrink down. 5. Not essential, but my header pins were a little long which made the UBEC and ESC servo plugs look as though they weren’t fully seated. I simply trimmed them with a dremel. 6.As the exposed legs will have approximately 6 volts DC on them, I recommend coating these in liquid tape or another insulation material. Epoxy may work just as well. This example weighed just 4.9 grams including the servo lead.