Electrical help needed

[Earl Findlay]

I am ashamed to admit that I have relied too much on my previous build partner and to this point have not used a tech counselor. I am at the point now where I need to install my panel. I feel lost. I know that I need to run wires and make harnesses but I don't really know how to do that. Is there a tech counselor or perhaps a builder near me that would be willing to help?

To some extent the show must go on. So a few questions:

Do I connect the master switch directly to the battery contactor? And does the other side of the wire connect to a piece of metal, which we can call a buss?

Do the circuit breakers each connect directly to the buss created above and the other wire to the component for the circuit breaker?

I have an IO-390A motor and I will have an electronic engine instrument setup in the EFIS. I will need to run wire to the motor for the instruments. How many wires should I plan to run from the MFD to the motor? Suggested length (longer is better and I will trim later)? Are red and green wires OK to use? I am thinking red for positive and green for negative.

I have decided to go with the Cummins Battery - 31, 950 CCA STUD Battery. I need to build a tray for it, but I am not sure how to determine whether the tray is sturdy enough? Is there some basic formula that I can use to determine how strong to make the tray? The battery weights 82.5 pounds and I am just not sure how to reenforce that weight onto a tray and have the tray be able to withstand the weight. Due to weight and balance I am planning to put the battery under the baggage floor, which is causing me some wiring planning troubles because I need to have a place to run the wire bundles from back to front. What have others done? Should I elevate the battery and run the wire bundle underneath the battery?

I think that this is all I've got for now. I am at a point in my build where I am feeling frustrated and a bit paniced because I feel like I am in over my head. But I have come this far, so I realize I am probably not as in over my head as I feel like I am. However, I do think a tech counselor is needed at this point.

[daveyator]

82.5 lbs...now THATS a battery
Cheers,
DaveH

[PaulvS]

This "how to" book (the Aeroelectric Connection) should be helpful and provide the answer to many questions and things you need to know:

https://www.aircraftspruce.com/catal...roelectric.php

[rv8ch]

Originally Posted by daveyator

82.5 lbs...now THATS a battery
Cheers,
DaveH

I snortled and sprayed my coffee on my keyboard!

Here's a great source of electrical information for homebuilt aircraft: http://www.aeroelectric.com

[mturnerb]

An 82 pound battery has no place in an RV - except maybe the kind with 4 or more wheels that includes a shower and toilet.

I'm dubious about the seriousness of your post. If you're building an RV-14 and feel like you're in over your head, why not read the plans and use the wiring diagrams, harnesses, battery tray, and battery that are part of the RV-14 kits?

Van's has a technical support line as well - might be a good place to start if you are serious about building a safe airplane.

[lr172]

Originally Posted by Earl Findlay

The battery weights 82.5 pounds...
I am planning to put the battery under the baggage floor...
... I feel like I am in over my head.

You are! I will restrain from further commenting, but will advise that you not undertake this kind of departure from the plans without a mentor. Your post strongly suggests that you NEED a partner with more experience than you. I suggest finding a new one.

Larry

[10builder]

Earl,

In one of your other posts you mentioned that you were receiving guidance from EAA1441 members. Maybe that would be a great place to start?

https://vansairforce.net/community/s...6&postcount=14

[iwannarv]

Buy the Aeroelectric Connection and Aircraft Wiring Guide books. It will get your head wrapped around basic architecture of your primary electric system.

Stick with the plans and don't install that battery - rediculous. Use what the plans call for, in the place it calls for.

[johnbright]

FYI:

Latest Aeroelectric Connection book free PDFs are at http://www.aeroelectric.com/Books/Connection/

Latest revs of Z dwgs are in the folder called "Adobe_Architecture_PDFs/" at http://www.aeroelectric.com/PPS/ There are updates since the book came out.

Bob Nuckolls and others answer questions on the Aeroelectric List hosted by Matronics.
.
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[Earl Findlay]

Originally Posted by mturnerb

An 82 pound battery has no place in an RV - except maybe the kind with 4 or more wheels that includes a shower and toilet.

I'm dubious about the seriousness of your post. If you're building an RV-14 and feel like you're in over your head, why not read the plans and use the wiring diagrams, harnesses, battery tray, and battery that are part of the RV-14 kits?

Van's has a technical support line as well - might be a good place to start if you are serious about building a safe airplane.

Can you suggest a battery with the same cold cranking amps but weighs less? My last RV had problems with warm starts due to not having enough power in the battery. It would die if you turned the prop over very much at all. The primary cause was the small battery, and my fix is a battery with higher amperage ability.

The plans for the RV-14 are not that easy to read. They are single pages with part numbers and measurements on them but I am having a hard time turning those things into reality. They are not 3D. Up to this point, Hal was reading and interpreting the plans and I would do as he instructed. But I have lost Hal.

I did not know that the kit included wiring harnesses for the avionics and switches. I have been working off of the assumption that those are custom to the builder and therefore not included in the kit. Can you point me to a part number or something I can use to find the harnesses?