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positive and ground wire.

stamper

Well Known Member
Did most everyone run two 2awg wire from the battery up to front both for pos and neg. or did most just run the positive and ground battery at battery tray. Just curious if I need to run two big wires up to front.
 
I have never run a ground wire to the front. Always grounded by battery tray.
 
Probably Not necessary

But I've always done it. And I single point ground everything to the forest of tabs on the firewall. I have no noise in any of my electrical systems, which I am kind of picky about. So I don't know if they would have been just as quiet without having run it.

Vic
 
I fall into the same camp as Vic. I spent a fair amount of time in Nashville as an audio engineer. So by default, I'm kind of anal when it comes to grounding.

I ran two fat wires and grounded everything to the forest of tabs. I don't have any electrical noise.

I think this is a dialogue like the primer wars. Both ways works just fine.

Bob
 
Local grounded everything. Used #2 ga. Sanded paint off of engine mount to firewall interface and applied dielectric grease at installation. Two bonding straps from engine to mount. My starter has pulled 438 Amps from my PC925L without a problem for over two years.
 
Thanks guys. It sounds both ways would work. heard something about if the ground wasn't as long as the positive wire it could cause some effect because the loop would be different. Did most of you quys use the vans wiring kit or do it yourself. Just trying to figure all the electrical out and what all I need. Sure would be easier if I was an airplane mechanic and not just a pilot. Feel like I'm wondering around in the fog.
Vans says these things are from first page to last a flying bird but I'm starting to see a different picture. I am glad all you guys are here. Thanks
 
I grounded locally, but all avionics are on a single point ground buss. I have no noise, not on intercom, CD player, xm radio, etc.
 
Local Ground

Not claiming to be an electrical guru just another point of reference.
I used Vans Electrical installation kit and schematic,heavily modified to suit my needs.
Although I did use a forest of ground tabs for a clean and orderly installation, grounds that are not from the instrument panel are grounded locally.
Audio is crisp and clean and there is no noise whatsoever.
 
If you have it local look it 2ga welding wire, its much more flexible than the standard 2ga wire. Cheaper as well, I believe I was able to get it for 1$ a foot at the local welding shop.
 
Thanks guys. It sounds both ways would work. heard something about if the ground wasn't as long as the positive wire it could cause some effect because the loop would be different. Did most of you quys use the vans wiring kit or do it yourself. Just trying to figure all the electrical out and what all I need. Sure would be easier if I was an airplane mechanic and not just a pilot. Feel like I'm wondering around in the fog.
Vans says these things are from first page to last a flying bird but I'm starting to see a different picture. I am glad all you guys are here. Thanks


If you want the basic functions that the Van's kit provides, it's a great solution. There are not many RV-10s being built today that fall into that category. You can buy the kit and modify it to suit your requirements, but my personal opinion would to start from scratch.

If you buy a copy of Bob Nuckoll's book, it has some schematics that provide well documented electrical solutions, in which one of them should meet your requirements.

The other option is to purchase something like Vertical Power VP/X Pro. It will dramatically speed up your electrical implementation and provide much greater instrumentation than the other options. For example, being able to see current flow per circuit allowed me to quickly isolate a problem and fix it. I highly encourage you to visit their website, even if you chose to go another route. Their documentation and planning guides are pretty good. One of the docs talks about common mistakes in wiring connectors.

This is much like the primer wars, you are going to see all kinds of opinions. I'm a fan of rolling your own solution. It may just take you a little longer to come up to speed. The benefit is that you will intimately know your aircraft's systems, not just how to turn all the knobs and switches.
 
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I'm also a big fan of Vertical Power, especially for the first time DIYer. The Van's kit was a big help my first time around because I had no idea where to start. Now I wouldn't touch it, but it does help you figure it out if you have no idea where to start.
 
I grounded the battery locally, the weight of a #2 in a-10 is a bunch. I also got the Vans wiring plans, they were a help in routing the big wires but the system is way to basic for any -10 being built today.

I designed a "hub" that did all the Dual Skyview wiring for me and has a seperate cable to each device and power/interfaces with the aircraft. The hub included two grounded 37 pin dsubs that were my forest of tabs. There are still some local grounds. No sign of noise yet, but the engine will not run for a few days

Drawings produced by a good old #2 pencil and a pad of paper. (30 sheets)
 
Instructions

Whether you purchase the Vans electrical wiring kit or not, get the plans for it! This is where you'll find all the instructions that'll fill in the knowledge gaps. As was previously said, you can deviate from these plans but they give you a good starting point and the hardware call outs. I think the plans cost $10.

D
 
Thanks guys. I think I will get Vans electrical plans and then go from there. My plane is starting to look more like a plane. I have two motors coming next week one for the rv10 and the other for the old super cub. So I will be having a big hang your engine day soon.
 
I bought the basic wiring kit. I found it was great as a starting point. Ok, I took apart the harness but used the individual wires. It also gave me lots of hardware for fitting everything - plus, the plans showing routings etc. I used pretty much all of it so didn't waste any money and it set me on my way.

As for the original question, local ground for all the major power users. Firewall ground for all the panel equipment. Tests so far show no noise in the audio. Running a second 2g ground all the way to the front strikes me as unnecessary extra weight and holes in the structure.

I do, however, intend to fit a 2g ground from the engine/mount strap to the firewall ground so I don't have to rely on the engine mount/firewall connection for the starter. Short run and no extra holes.....
 
I interpret the notes in the construction manual to say run the ground wire to the firewall. I did this without creating extra holes. Originally I used #2 welding wire. My local A & P convinced me, as stated also at an EAA electrical workshop, welding wire can release a toxic gas if it gets hot. Also my A & P said welding wire absorbs and swells when in contact with engine oil in the engine compartment. He also convinced me that 0 gauge wire never gives him a problem starting the engine. Therefore, right or not, I removed the welding wire and ran positive and negative 0 gauge wire forward to the firewall. A little extra weight, but in balance, I like the value these changes will give me.
 
I'm in the camp of "the ground must be as good as the positive lead - it carries the same current".

What I did different:
- used #2 welding cable for the lead from the combined output of the two battery master solenoids to the starter solenoid on the firewall. The #2 welding wire was far easier to work with than the alternative. I did a test on the welding wire using a torch - the insulation did not support combustion and although charred did not fail. I got a 100' spool off eBay for a song (new wire made in the USA) and it got distributed to three RV projects.
- For the left/right vital power from the batteries I used a single #10 wire for each side (half the panel is on each side, and the power for each side is selected between the batteries and is independent of the two master relays).
- As the power to the panel was now not dependent on a single lead or relay, I made the ground leads independent as well. Each battery has (4) #10 wires for the ground lead. One battery ground goes up the left side, the other up the right side of the fuselage. Three from each battery end up at the left firewall ground, one from the right side end up on the right vital bus ground tab behind the panel and also grounded at the batteries. It also has a jumper wire to the firewall ground. The remaining ground from the second batteries is also grounded at the batteries. These #10 wires in parallel have more cross area than one #2 wire.
- The engine has a single #4 wire for ground running between the firewall ground stud and the ground stud on the starter. The starter is where you want the best ground on the airplane as it draws the most current. While this is possible with a ground strap to the engine, I believe the starter provides the best location.
- The wing components have a common ground lead that ends up at the firewall grounding tab. Nothing in the plane is locally grounded to the fuselage.

So - why do this?
- A single ground connection has the same potential of failure as a single positive lead to a single master solenoid. Don't fix one without addressing the other.
- The multiple #10 ground wires proved to be far easier to run then the single #2 welding wire. The added aspect of independent ground paths for the panel supports the independent power distribution and addresses the single point failure issue.

For what it worth, I looked at the VPX system and understand why it would be attractive if one is looking to replicate a traditional power distribution scheme. As I took a different path the VPX would not fit the bill.

Carl
 
Did most everyone run two 2awg wire from the battery up to front both for pos and neg. or did most just run the positive and ground battery at battery tray. Just curious if I need to run two big wires up to front.

It doesn't have to be that big of a wire, but indeed run it up to your ground bus and join it with a thru firewall ground. Using the airframe as a ground these days, esp in a more complex plane, is just lazy. Do it right!!
 
It doesn't have to be that big of a wire, but indeed run it up to your ground bus and join it with a thru firewall ground. Using the airframe as a ground these days, esp in a more complex plane, is just lazy. Do it right!!

But does have to be the same size of your power cable.

I went conservative and not wanting any current loss due to wire length. I ran 2awg welding cable. I also have two independent batteries and buses in my RV-10.
 
It doesn't have to be that big of a wire, but indeed run it up to your ground bus and join it with a thru firewall ground. Using the airframe as a ground these days, esp in a more complex plane, is just lazy. Do it right!!

While I don't have a problem with running a separate ground wire from the back to the front of the plane, calling it "just lazy" is taking it too far, IMHO. It adds weight. It weakens structure (an extra 3/4" hole in every bulkhead it has to go through). Saying that every wire should be 18AWG or larger would be in the same thought process in my mind. The airframe of our RV's are very effective ground paths. I would rather have 2 ground wires bolted to the airframe next to the battery (2 separate places) than one running to the firewall. Using the airframe as the ground, which it will be anyway no matter where you run the ground wire to, unless you isolate it from the airframe, has worked well on thousands and thousands of airplanes for scores of years.

Again, I don't have a problem if someone wants to run an extra ground to the firewall, but not doing so can have many reasons that are not just laziness.
 
Ditto on Vic's way. 2Ga Positive and Negative all the way up front. Noise free and wanted to not have to troubleshoot gremlins. Haven't had to and its been almost 10 years now.
 
So, other than Vans, where do you order your wire and electrical supplies, i.e. if you wanted mil spec grade wire. I checked Aircraft Spruce and Wicks, but are there othe suppliers that offer better pricing.
 
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