Installing 3000 W inverter – wire size – fuze size

[TenOC]

I am thinking about adding an 3000 W inverter to my RV. What size fuse should I put in the 12 Volt line from the battery to the inverter? Do you have a recommended brand name? I have also read that some inverters come with cables that are undersized. What size would you recommend?

[mrshane]

For a 12 V battery bank, you would need a fuse size of around 300 A or more, and cable size of around 2/0 AWG or 4/0 AWG 

[pianotuna]

TenOC I have a Magnum hybrid. If I were purchasing again I'd go Victron Hybrid. (hybrid units do load support but not voltage support.)

[StirCrazy]

a 3000 watt converter can pull up to 250 watts at 12V so add 10% minimum to that and you get 275amp fuse so what ever the next size up from that is.  as for wire, you have to determin how far the batteries and inverter are apart and take the total run leng into account so if you have them 3 feet apart you will have a run length of 6 feet.  then look up how big of a wire size will handle 250 amps for  distance of 6 feet and then you have to take into account the voltage drop your happy with dealing with.  for example if as above the return distance is 6 feet (or less) and you want to have a 1% voltage loss then you need a 4/0 cable.  

[enblethen]

250 amps not watts!

[StirCrazy]

yup, but this new board setup won't let me change it now.  

[enblethen]

Wire size needs to be determined by distance be batteries and inverter. fuse size will be large somewhere around 250 amp.

Installation manual should give you some specifics on wire size and fuses. Yes, many inverters have cables supplied but many are undersized. Off hand with in ten feet or so you would need 4/0 cable something like welding cable. More strands in cable would be better and more flexible.