Battery Question

Getting ready to place an order with Spruce.

I'd like to go ahead and order my main battery lead.

I've mounted my battery box in the Vans recommended location, and I've also mounted my VP/X in the recommended spot (inverted between the middle and left rib just back of the firewall).

By my math 5 feet should be plenty of wire, so 8 gauge should be fine, right?

Also, what size firewall penetration are folks using for all the wires that need to go through the firewall on the right side?

I'm planning on bringing the engine monitoring wires through on the left side.
Will a 1/2 inch be enough or should I go with the 3/4?

Thanks,

-Dan

Which wire?

#8 wire to supply the alternator output to the battery will be fine but I doubt you want to use #8 wire for the battery lead. You will probably have starting issues as starters can use extremely high current (150-200 amps) albeit for a very short period of time. Cold starting will prove a challenge. Likely you would be much better served with #4.

I recommend you go with the larger firewall penetration. You will have to run a lot through there and may need room for expansion due to future enhancements to the plane. They are easily sealed. I built mine with flanges on the firewall to firesleeve which turns in on itself and is clamped to the wire bundle with worm clamps.