Proper wire gauge for accessory plugs?

[smcdonaldaz]

Howdy! I'l thinking about adding a couple accessory points in the back seats for the kids to plug in their iPods and at most a 400w inverter I have. What gauge wire would be best and would an inline fuse be best or should I add a fuse box off the battery? Your suggestions are much appreciated.

 

[Gerr]

well from my experience you should plan on the future mods being more than you expect. Id run at least a 10g wire to a fuse block then from there a few extra circuits for the different things you have to run now and leave one or two for future use. I personally ran a 4g wire to a 10 circuit block

 

[alfman]

If you run any wire back for a power source make sure you put a fuse within a couple of inches of the attachment point of the main wire (be it the battery or a power lug on the fuse block). I would run a larger gauge wire back to a fuse block and split it from there. If you're going to run an inverter make sure the main wire running back is larger than what is called for in the inverters manual especialy if you will run anything else 12 volt off that wire.

 

[MoFo]

When you are converting from 12V to 120V, if you had a 100% efficiency on the inverter, the input current would be 10X the output current. The best you will see with these inverters is about 90% effeciency. The efficiency drops with the percent of maximum rated load you are running. I recommned you do not run the inverter with the engine off. So you can figure your maximum draw on the input will be 440 watts.

440w / 13.5v = 32.6 Amps

You should consider puttng the accessory outlet in the back of the console to keep the wire run as short as possible. I would guess that run at about 12 feet to the power distribution panel. I would not do this with any smaller than AWG 8 wire.

 

[badron]

If the converter is 400 watt output. It will need it own line. This fused line should come right from the battery or the battery terminal on the starter. DON'T tap into the OEM wiring for this much of a load. Many converters are also DC voltage sensitive many will drop off line when battery voltage drops to 9.6 volts or so. So if you lose 1.5 volts to the DC line lose on a long lead to the back. The best the converter will see is 11.? volts thats with the key off. Leads to it should be as short as possible. Just use an extension cord on the 120 side to get the power were you need it.
Some say don't use a converter with the engine off. It will drain the battery very fast.
Others say don't run you engine with it in use, The large load over what the charging system was made for will over heat your alternator. But this for the most part can be over come by killing any load not need at the time of use.
Many accessory outlet are rated at 20 amp max. But I have found them unreliable at that load. I would hold them to 15 amps and save a melt down of the plug. One lead to both will do if it a biggy.

 

[smcdonaldaz]

Thanks for all your advice guys. I think I'll run 8 gauge back and run a separate connection for the inverter.

 

[whatevah]

two 8 gauge runs sound good. I'm running 4 gauge to a 2-place 8 gauge distribution block. Mainly because I had the 4 gauge handy. One runs to an amp, the other is (eventually) for a relay box.