Tail mounted battery and ground return?

[dwilson]

Building an RV-10 and plan to put the batteries in the tail. Using Bob N.'s Z-14 diagram.

Question is, do I need to run a AWG#2 all the way back to the - side of the battery from the engine compartment or just ground the engine braid to the firewall and ground the battery to the airframe and let the airframe take the current back to the battery from the starter/alternator?

Thanks,

[Mike S]

The RV 10 uses a rear battery, and airframe for a ground path.

Works just fine.

If you want to spent the $$$, and carry the weight, you might realize a small advantage with a dedicated ground. But I suspect the difference will be somewhere between unnoticeable, to not worth the trouble.

BTW, these are scientific terms.....

[Ironflight]

I suspect that this thread could grow to a very great length with the debate on local versus common ground - but I'll add my experience to Mike's thoughts - more than three decades of flying airplanes with the rear mounted batteries grounded locally, and never had a problem. The airframe is a pretty good return!

[dwilson]

I appreciate your input Mike and Paul.

That is kind of what I figured, but it is nice to have an outside opinion.

I will be grounding locally.

[apkp777]

It's a good idea to use an aluminum "bonding brush" available from the "yard". Really assures good conductivity.

http://www.yardstore.com/browse.cfm/4,5948.html