Wiring Solar System into Camper Van

[Melonie]

Hi all,
I am putting a solar and second battery system into my van and want to have a go at doing it myself. No previous experience or knowledge. I've done some research and calculated the size of battery and panels I will need and drawn up a wiring diagram for the van. I'd love for someone to check over it and also if someone could point me in the direction of a good resource for calculating wiring sizes. All help is much appreciated. Thanks! Melonie Wiring Diagram.png

[Sunking]

OK first don't give us a line of BS that you laid this out. This is a kit you copied and pasted. Here is a chart that will tell you what size wire to use based on Fuse Size. Use 3% Critical Load. FWIW with the Battery Idolator, you do not need the solar.

DC_wire_selection_chartlg.jpg

[Melonie]

OK first don't give us a line of BS that you laid this out. This is a kit you copied and pasted. Here is a chart that will tell you what size wire to use based on Fuse Size. Use 3% Critical Load. FWIW with the Battery Idolator, you do not need the solar.

DC_wire_selection_chartlg.jpg

Well when you find that image anywhere on the internet let me know haha. Thanks for the wiring chart.

[Mike90250]

First, your fuses at the battery. If you only needed 2 terminals, you could use the simple

https://www.bluesea.com/products/2151/Dual_MRBF_Terminal_Fuse_Block_-_30_to_300A

but with 3 terminals, it gets more complicated and you must fully protect the exposed wire

https://www.bluesea.com/products/5196/MRBF_Surface_Mount_Fuse_Block_-_Common_Source

The fuses should be at the battery, and not hanging on 2 feet of wire. Any unprotected wire can short and cause a fire.

The wires to the DC voltmeter need a fuse, and it should be wired to your load panel, so you can see if a major fuse blew, giving you 0V

The wire to the charge controller needs a fuse - if the controller dies, you get fire without a fuse

You need a switch (or a DC breaker) for the inverter, if it starts to smoke, you may not be able to reach it's own switch.

Your thermal-electric cooler (fridge) consumes a LOT of power, and generates a lot of heat . Don't expect 1 battery to carry it overnight, or get fully recharged the next day, that fridge will be sucking 10 A from the panels that I'll bet you expected would be charging the batteries.

[Melonie]

Your thermal-electric cooler (fridge) consumes a LOT of power, and generates a lot of heat . Don't expect 1 battery to carry it overnight, or get fully recharged the next day, that fridge will be sucking 10 A from the panels that I'll bet you expected would be charging the batteries.

Hi Mike,
Thanks for all the info on the fuses and switch, very helpful.

Planning on also having an electrician install a 15A power inlet so can run the fridge off mains when on a powered site. But yes outside of that I'd anticipated the panels and driving during the day would power the fridge and charge the battery enough to get by. Fridge draws 6.5A @ 12V and 0.32A @ 240V. Would running it through the inverter (when not on a powered site) get by since the power draw is so much lower? Thanks!

[Mike90250]

No, you count wattage for power loads, not amps
12v x 6.5A = 78watts
240V x 0.32 =76.8watts, plus another 20% losses in the inverter = 93W

[chrisski]

If that 115 ah battery works safely, for any amount of time with that 1500 watt inverter, I've done something wrong with my calculations. When I looked at going above 1000 watt inverter with 400 ah of batteries and 600 watt panels, I start fearing burning down my RV.

That seems to be a trend for many of the kits that you get off the internet. A 1500 watt inverter with a 115 ah battery. Most if not all from China. Most if not all from companies that do not seem to have a long history, perhaps since the last lawsuit. A lot of the inverter website I am looking at have complaints about the inverter cutting out before it can reaches the full potential. Also, a lot of sites said the 6 AWG provided wire would give off the smell of melting insulation, so it was switched to something thicker.

Run anything stronger than a single cup electric coffee pot, probably needs more than 1000 watts.

A bigger propane fridge will be much more economical than upsizing your system to run that fridge through the night.

A few months ago, when I started putting my system together, I thought that diagram you put up would get me through a day or two. I'm ending up spending about three or four times more than I thought. I thought I would have been able to do it all off a kit ordered from the internet.