A Step By Step Guide To An Awesome Powerful Fully Off Grid 12v Set Up - PART 4

Updated: Jun 1, 2021

Welcome back to PART 4 of our post.

If you have found this post via a link and want to catch up with the post so far please click the links in blue to take you to PART 1, PART 2 & PART 3

If you have already read PART 1, PART 2 & PART 3 and are ready for PART 4 of our post here it is, we won't wont waffle on we will just straight into it and pick up where we left of and that was adding a socket to your bed side area so you have somewhere to charge your devices when you are in bed or power a radio alarm clock etc.

These don't really need to be anything special but there is no point in buying technology that will be obsolete soon so you might as well go for something like another one of these so you have a choice of outlets with a very simple install. As an amazon associate I earn from qualifying purchases

GemCoo PD Type C Car USB Socket 46W and QC 3.0 18W 12V/24V Car Power Outlet Waterproof 64W Dual USB Charger Socket


To wire this to your fuse box couldn't be much easier and you do it just like you have done with all the sockets you have installed so far.

First run a length of 11amp twin core cable from your 12 way fuse box to the bed side area where the socket will be installed, next attach a female spade connector to both the positive (red) and negative (black) cables at the socket end... please see picture below.

Next attach the positive (red) cable to the positive (+) terminal and the negative (black) cable to the (-) negative terminal on the back of your socket...

At the fuse box end on the cable attach a ring crimp connector to both the positive (red) and negative (black) cables.

Screw the positive (red) cable to any spare positive (+) terminal and the negative (black) cable to any spare negative (-) terminal on your 12 way fuse box and you should have something that looks like this... Please see picture below.

And the last thing you will need to finish off this circuit and your final socket is a fuse, as this is 11 amp cable you should use a 10 amp fuse.

You should now have something that looks like this...

That is also the last thing we will be adding to the fuse box for now, you might have noticed that there are still 5 x free terminals. This is for two reasons the first is that we have lots of optional extras in the final part of this post that will need all need a terminal on a fuse box and also incase there is anything extra you wanted to add yourself like another roof fan, circuit of lights or another set of sockets as now you know what you are doing you can add whatever you like really.

In our ADDED EXRAS AND UPGRADES to this system post we will be adding a bathroom/shower room 12v water set up, a freezer, a real time tracker, flushing toilet, a DAB radio and a few other awesome bits and pieces to this fuse box as well as some awesome ideas for any bits and pieces you might have left over so make sure you check it out when we post it!!

There are a couple more things that we are going to add to this set up before we finish though and the next thing we are going to add to this set up is a heater.

If you follow our blog then you already know what we are about to suggest and if you don't we will save you all the trouble of hours spent researching the best way of heating your van during the winter.

The best thing to use is a diesel heater to cut a long story short, anything that runs on electricity will drain your battery bank in less than a night, a log burner requires lots of time attention and space for both the burner and fuel and propane creates damp heat that will make everything damp unless you get a sealed unit like a Propex and that is mega bucks and still not as good as a diesel heater for many reasons.

So the choices for heaters are a Chinese diesel heater. These cost about £100 per unit and thousands of people in the UK use them and love them and have nothing bad to say about them... We all use them and love them. The down side is they do not come with any warranty.

For more info in these heaters please take a look at our posts on diesel heaters

Then there are Planar/Autoterm these heaters are the next step up, Russian and come with some cool features like the ability to control them from your phone and to be able to automatically adjust settings to fuel and air depending on your altitude... thats pretty cool however these will set you back about £750 fitted but come with a long 3 or 4 year warranty depending on wether they fit it for you or you fit it yourself thats pretty good.


And then there are the big boys on the market for any of you that might have won the lottery recently or have just ran out of your bundles or £20 notes that you have been feeding into your wood burner to keep you and your golden egg warm in your 4x4 amphibious Sprinter vans...

Eberspacher & Webasto. They will set you back about £1000 and above fitted and will cost you twice as much as a Chinese diesel heater costs to buy just to have somebody to come and have a look at it if there is a problem with it (not including parts)

That being said they are really well made and will last for decades.


For this build, the sake of the diagram and for the fact that we already have a full installation guide for it on our blog we are going to recommend a Chinese diesel heater, to see how to add this to your set up please follow this guide....

So you should now have something that looks like this...

The final thing we are going to add to this set up (before the ADDED EXTRAS & UPGRADES post is an inverter however not everybody will need to install one of these.

As this system will work completely off of 12v you only need to add an inverter to the set up if you have a specific 240v appliance/accessory you want to plug into in to it and the size of the inverter depends on what you want to run off of it. Like we said in part 3 of this post if the only 240v power you need is for charging a laptop or camera battery etc 300W is more than enough so you could just use a small 300W inverter that plugs into your 30 amp lighter socket and you are good to go.

Laptops and battery charges are normally quite low powered for example my mac book charger is only 60w so even with peak power requirements 300W will be more than enough

If you want to power something more powerful like a 700w microwave for example you will need to go a lot bigger as the peak power rating is normally at least twice the actual watt rating on the appliance. So that would be at least a 1000w pure sine wave power inverter with a 2000w peak power rating.

if you start going much higher with the wattage of the inverter than 2000w or 3000w then then cable sizes would need to be very thick to carry the correct amount of amps and also the higher the wattage of the inverter the bigger the drain on your battery bank even with only a small load.

So when choosing your inverter you can't go to small or it will not power your equipment and you shouldn't go to big for what you need because it an unnecessary drain, this is why we say if all you have is a laptop charger then there is no need to go over 300W

A decent sized inverter to install that could be used for most things when needed would be a 1000W or 1500W pure sine wave inverter so that is what we are going to suggest for this set up then if you ever need to use a microwave, power tools, or plug something random in you should have no problems

Pure Sine Wave Power Inverter 1500W DC 12V to AC 230V 240V with 4.5m Remote Controller LCD Display Dual 2.4A USB Port 24-month Warranty


You will need to wire this directly to your battery bank via another inline fuse/circuit breaker, the peak power rating of this inverter is 3000W so the cable will need to be able to carry at least 250 amps as

3000W ÷ 12V = 250A

So for this you will need...

Mottdam 300A AMP Car Circuit Breaker 12V-48V DC


Battery Cable 50mm2 4X M8 Cable lugs Each 1m Cable red and Black


Cable Lug 50mm2 M8 4X Cable Shoe