Electricity in my camper

[AshleyDC]

Hi,

I've been racking my brains and scouring the internet for help in this field and can't get to the bottom of any of it. I'm converting a van into a camper and trying to plan the DC and AC circuits. This is the plan in the following link if you could please take a look: http://imgur.com/gallery/DmSpy

My doubts are, what fuses to use and what cable sizes to use. Can anyone help me out with this?

 

[binky]

that's a pretty comprehensive set-up.

You want to keep the DC battery side as short as possible, look under the bonnet of any car and you will see how large the battery wires are.Once past hte various charge controllers and DC-AC inverters cables will be pretty much normal for housing circuits. The 12V lights and stuff would work quite happily in 1mm. If you have an electrical background, the charts in the back of BS7671 apply to DC and AC circuits. failing that, have a look at some of the cable manufacturers websites, most have cable calculators of some sort. I haven't got my copy of BS7671 to hand, so will leave it to others to suggest sizes.

 

[M107]

Antares TDC have some good design tools (I've got one of their CX-V power chargers to fit on a narrow boat tomorrow charging a leisure ban & the start up battery)

http://www.antares.co.uk/design-tools.html

http://www.12voltplanet.co.uk/battery-chargers.html

12 volt planet are a good supplier....use thin wall cable for the DC 12v circuits.....AC circuits  use 1.5mm² or 2.5mm² 3 core sheathed flex cable.

For battery protection fuses consider using http://www.12voltplanet.co.uk/waterproof-switchable-surface-mounted-circuit-breakers.html

You have the 12 fuse box & inverter fed from the solar regulator (is it a regulator or charge controller?). I'd take the feed direct off the leisure battery bank.

You'll need a blocking diode between the regulator & the battery bank, without it at night you'll get a small drain off the batteries to the panels.

The mains battery bank charger..... look a unit that will will provide power charging, basically it will simultaneously work as a charger & power supply (via the batteries) to 12v loads without gassing the battery bank. The Cx-V units also provide a sperate charge option to the start up battery

You might want a relay employed between the solar & mains charging so only one is in use at any one time.

 

[AshleyDC]

Cheers for the replies guys, every little helps! but now I have more queries!

I have little or no electrical background really, but I'd like to know how to work out things like fuse /breaker amp sizes. for instance: 

A fuse between the battery and the regulator (it's a regulator and controller in answer to your question M107), the amp size of the fuse/breaker would be worked out by the total sum of amps drawn from all appliances if you had the full load going, and from there you could also work out necessary cable thickness, knowing the amp load... am i right here?? and same goes for the cables and fuses/breakers from the regulator/controller to the inverter or 12v fuse box?

Say if I we're to calculate that, on my 12v system, when all appliances are on, they're drawing 30amps, I'd want a 30/35 amp fuse from regulator to fuse box connected with 10mm2 cable (thats just what the graph tells me for a 34 amp load). Is this in the ballpark??

Now, the relay to select between solar charge and mains charge, is this a manual switch, like a line selector? 

From what i understand about diodes they block the flow of current in a certain direction. The issue is that the regulator is also a controller, so i need the batteries to run back to it to then go out to 12v fuse box and inverter. So could i install the diode between the solar panels and the regulator to achieve the same goal? i think i read somewhere that diodes provoke voltage drop... is this correct?

Lastly, between the two 150w 12v solar panels in parallel and the regulator, I've been told by one electrician to use 6mm2 cable  and by another to use 10mm2 with a 20Amp fuse/breaker, what method are they using to work this out? I'd say that 150w divided by 12v would be 12.5amps, times it by 2 to get 25amps, meaning I'd use 6mm2 cable with a 25 amps fuse into the 30Amp regulator/controller.

Lastly lastly, i have no idea what amp size breaker/fuse to use from starter battery to leisure battery, as there are no appliances involved, how do you know the amp draw from one to the other?

I know there are a lot of questions going on here, and whoever takes the time out to hep is an absolute saint!

Thanks again,

Ash.