Vertical Power and E-buss

[RandyAB]

I'm struggling with designing the most efficient way of integrating a Vertical Power Pro with an ebuss for backup. I'm not sure if I'm missing something and would appreciate kind input to get me on the right track.

Firstly, my system is going to have dual alternators and dual batteries. The SDS system is going to be wire on it's own buss, independent of Vertical Power with the avionics powered mainly through the VP, divided between the two busses that the VP Pro offers. I'd like to backup my critical avionics via a separate ebuss. I've studied backup method B and C in the VP install manual. What I don't like about these methods is that they seem to demand a switch for each piece of backup equipment. I'd prefer to be able to just power the ebuss with one backup switch and eliminate the others if possible. One solution that I'm looking at is using a Power Deuce Schottky like this one and feeding power in by both the ebuss and the VP.

http://www.periheliondesign.com/powerschottkydiodes.htm

Is this an acceptable solution? Is there one that is simpler that I am overlooking? Perhaps I am overthinking. Helpful advice is appreciated. Preemptively, I am most of the way through Nuckoll's book and have been once through Ausman's book as well.

[Southern Pete]

I might take some abuse for saying this, but do you really, really want a VPX? You have a dual redundant system, but are planning on sending all your electrics through the VPX. That makes no sense to me, even with an e-bus you will end up duplicating much of the VPX that makes it not really worthwhile. What benefits do you get from the VPX?

With dual alternators and batteries you have decided you need the redundancy of 2 separate generating systems, that can provide redundant power supplies to the SDS. Provide 2 power inputs to the SDS in case one quits. How feed one busbar from both sources with a diode on each feed to prevent one bus back feeding the other. Now hang fuses from the bus to power your services. The alternator with the highest voltage will power the supplies (assuming it has the power to do so).

Write a list of what the VPX gives you and how to achieve those features without it and determine the value it is providing to your system. If it is worthwhile connect it to the bus described above; if it fails you will not lose the engine or critical avionics.
Pete

[rleffler]

Originally Posted by RandyAB

I'm struggling with designing the most efficient way of integrating a Vertical Power Pro with an ebuss for backup. I'm not sure if I'm missing something and would appreciate kind input to get me on the right track.

Firstly, my system is going to have dual alternators and dual batteries. The SDS system is going to be wire on it's own buss, independent of Vertical Power with the avionics powered mainly through the VP, divided between the two busses that the VP Pro offers. I'd like to backup my critical avionics via a separate ebuss. I've studied backup method B and C in the VP install manual. What I don't like about these methods is that they seem to demand a switch for each piece of backup equipment. I'd prefer to be able to just power the ebuss with one backup switch and eliminate the others if possible. One solution that I'm looking at is using a Power Deuce Schottky like this one and feeding power in by both the ebuss and the VP.

http://www.periheliondesign.com/powerschottkydiodes.htm

Is this an acceptable solution? Is there one that is simpler that I am overlooking? Perhaps I am overthinking. Helpful advice is appreciated. Preemptively, I am most of the way through Nuckoll's book and have been once through Ausman's book as well.

I have a VPX/Pro, two batteries, and two alternators. I have a pair of switch/contactor that can isolate or join each battery to the main buss. I use the diode in your link to ensure that the ebus battery is charged when isolated. It's more or less a combination of the two backup methods in the manual.

You're still stuck with adding more switches. Many devices, such as the Garmin GTN650, don't have a back up power input. You'll need a switch to move the power source from the main bus to the ebus.

I've been flying for over five years and haven't had an issue arise that this configuration wasn't able to handle.

[RandyAB]

Originally Posted by Southern Pete

I might take some abuse for saying this, but do you really, really want a VPX? You have a dual redundant system, but are planning on sending all your electrics through the VPX. That makes no sense to me, even with an e-bus you will end up duplicating much of the VPX that makes it not really worthwhile. What benefits do you get from the VPX?

With dual alternators and batteries you have decided you need the redundancy of 2 separate generating systems, that can provide redundant power supplies to the SDS. Provide 2 power inputs to the SDS in case one quits. How feed one busbar from both sources with a diode on each feed to prevent one bus back feeding the other. Now hang fuses from the bus to power your services. The alternator with the highest voltage will power the supplies (assuming it has the power to do so).

Write a list of what the VPX gives you and how to achieve those features without it and determine the value it is providing to your system. If it is worthwhile connect it to the bus described above; if it fails you will not lose the engine or critical avionics.
Pete

Thank you Peter for your input. I appreciate it. I really do like the functionality of the VPX system overall. From what I've read, the dual independant busses of the VPX Pro with the ability to provide backup power input is inherently a safe design that should make an emergency a very unlikely event. I will dwell a bit more on what you've suggested. Thank you.

[RandyAB]

Originally Posted by rleffler

I have a VPX/Pro, two batteries, and two alternators. I have a pair of switch/contactor that can isolate or join each battery to the main buss. I use the diode in your link to ensure that the ebus battery is charged when isolated. It's more or less a combination of the two backup methods in the manual.

You're still stuck with adding more switches. Many devices, such as the Garmin GTN650, don't have a back up power input. You'll need a switch to move the power source from the main bus to the ebus.

I've been flying for over five years and haven't had an issue arise that this configuration wasn't able to handle.

Thank you Bob for your very helpful comments. The GTN 650 that I plan to use as you did really presented the greatest challenge because of the lack of dual power inputs. I wasn't completely sure that the diodes that I referenced were the correct way to approach the problem. I'm very glad that that you have experience with them and that you utilized them as I am considering. I will draw out a main power distribution plan and post it once I've had a chance to do so. Perhaps at that point you could offer an opinion as to whether what I've come up with is as good as your system and offer a critique at that point. Thanks again.

[cdeerinck]

Randy - send me an email at cjd9 @ me . com and I can send you my schematic if you would like. I am doing a very similar thing.

[RandyAB]

Originally Posted by cdeerinck

Randy - send me an email at cjd9 @ me . com and I can send you my schematic if you would like. I am doing a very similar thing.

Thanks Chuck! I?d love to see what you are doing.

[leok]

Originally Posted by rleffler

Many devices, such as the Garmin GTN650, don't have a back up power input. You'll need a switch to move the power source from the main bus to the ebus.

The GTN650 does have dual power feed. In fact it has 6 power feeds since the GPS/Comm/Nav all have separate dual feeds. Connector P1001 pins 19 and 20, connector P1003 pins 43 and 44, and connector P1004 pins 51 and 52 are all power and backup power connection pairs. I asked Garmin if I should feed all 6 connections separately. They told me most installers hook them up 3 and 3 to two separate power feeds.

I have a VPX in my system with an e-buss. It only added one extra switch to select the e-buss. I feed a small, e-buss blade fuse box, direct from the battery with a 15 amp resetable breaker. This bypasses the master as well as the VPX. Here is a thread with details on my system http://www.vansairforce.com/communit...d.php?t=152279

[majuro15]

I'm very similar, planning a switch to a second, isolated battery that powers the engine bus and IFD 440 and PFD (with ems). The battery remains charged through a diode.

I can kill the entire system with the master then flip the "oh ****" switch which then brings the second battery online and restores everything needed to run the engine.

I don't see a need for two VPXs. There is a point where a system just gets too complex. VPX advises not to run an engine system through it anyway. My engine bus is powered from the PPS with a separate power wire going to the VPX for all the other stuff.

[Carl Froehlich]

Originally Posted by leok

The GTN650 does have dual power feed. In fact it has 6 power feeds since the GPS/Comm/Nav all have separate dual feeds. Connector P1001 pins 19 and 20, connector P1003 pins 43 and 44, and connector P1004 pins 51 and 52 are all power and backup power connection pairs. I asked Garmin if I should feed all 6 connections separately. They told me most installers hook them up 3 and 3 to two separate power feeds.

SNIP

This is interesting. I just looked at the install manual again and while there are separate pins for power as you discribe, my impression was these are not separate feeds, just smaller wires in parallel to handle the higher current (page D-8 of the install manual is example).

Are you confident that the GTN-650 has independent power input capability?

Carl