Typical Fuse size for DC Voltage

[bowhunter74]

Hello Everyone,
I have been working on converting my 6x10 Trailer as our new hunting lodge when we head out on our weekend hunting trips. My major question is dealing with the electrical. I have seen multiple posts on here and I plan on implementing a few ideas to keep the costs down.
Currently I use the 20 Amp Marinco plug and the built in GFCI power strip. It’s a lot like this one: http://tnttt.com/viewtopic.php?f=30&t=37732
The next beast is the DC power. I have a mounted battery box on the front of the trailer with a very large Deep cycle battery. I have 8 Gauge wire ran into my trailer and that’s where I stopped. I have a Blue Seas fuse panel, but need to add a fuse or a master cutoff switch. I guess my major question is how big of a fuse do I need?
I will have a 750 watt inverter in the mix as well. I was going to have 2x LED porch lights on each side of the trailer, 1 to 2 flood lights on the back of the trailer in the event we need to some cleaning and a few puck lights internally for lighting. The converter will be running my CPAP when I am sleeping and to charge are phones. I was thinking I could get away with adding a 30 Amp inline fuse off the battery box. Internally to the trailer add the master cutoff switch and then feed it back to the fuse panel. I plan on changing out the 4 pin connector to a 7 pin connector so I can have my new truck charge the battery as we are driving down the road.

The only things that could be added down the road is a TV and extra lights, but that is about it.

Thanks for your time to help me out.

[MtnDon]

I will have a 750 watt converter in the mix as well. ......... The converter will be running my CPAP when I am sleeping and to charge our phones.

That is an inverter not a converter. Inverters take DC power and make AC power. Converters do the opposite;take AC and make DC and can charge a battery.

Inverters almost always come with a user guide that lists the size of the fuse to use in the DC supply + wire. IF that inverter can supply up to 750 watts of AC then the minimum fuse size for the maximum power output would likely be in the 80 to 100 amp size range. A 30 amp fuse on the DC inlet size might be large enough to supply the wattage you would use for just a CPAP.

You can get a disconnect as simple as one of these that attach to the battery negative terminal.

A circuit breaker has advantages over a fuse, mainly that one can usually also be used as a disconnect and is reusable. One of many


For charging phones it would be more efficient to wire in one of the 12 VDC plug accessories that provide one or two USB charge ports. That avoids the inverter losses that using a wall wart charger would have.

[bowhunter74]

Thanks, sorry for the converter/inverter wording. I know what I wanted to put there, but I don't think the coffee has kicked in yet.
I plan on adding a panel like this for the phones off the 12V side. http://www.amazon.com/Digital-Voltmeter ... ds=12V+usb
With 8 gauge cable isn't my max limit for amps is 62? So would this be a better choice for a breaker? http://www.amazon.com/Bussmann-CB185-50 ... 12v+50+amp
If I use one of these type breakers would I be able to remove the master cutoff switch out of the diagram?

[Dalorin]

Search the forum. I asked a similar question about fuse sizes and noseoil kindly supplied the chart you need.

[MtnDon]

Sorry, I was concentrating on the fuse or breaker size not the wire. The 8 gauge would not even be rated for 62 i think. I'm on my phone and find itdifficult to access some of my references but depending on temperature i believe 8 gauge is maybe only 50 amps or so. My preference is to use wire and fuses to match the inverter capacity... you never know what you might want to use someday.