For our system, we are using a 150 watt monocrystalline solar panel from Renogy (**we added a second one later on so the wiring diagram shows the two panels). In a nutshell, polycrystalline is cheaper but monocrystalline is more efficient. We opted for this one mainly because it’s square so it fits nicely within our roof rack. We’re fairly light power users so 150 watts is sufficient for us, but take some time to pay attention to how much power you actually consume in a day. Take note of the wattage rating on your appliances too – you’d be surprised how much power some small appliances take. Use resources like Renogy’s calculator to help figure this kind of stuff out.

The panel is hooked up using two MC4 connectors (wtf are those?! read this) to join the positive and the negative 10 AWG wires that come already attached to the panel to the positive and negative 10 AWG wires that feed inside. Home Depot has a handy guide for understanding wire thickness, or read more in-depth about it here. As mentioned, we already had a roof rack so we just ran two sturdy metal beams across and used z-brackets to secure it on. Depending on what your roof’s shaped like, you can easily mount the z-brackets directly onto the roof as well. We drilled two holes in the corner of the roof and sealed on a little cable hub to feed the wires through while keeping it water-tight. On the positive wire, we’ve used a 15 amp breaker but you can also use a standard fuse. The breakers are a little more expensive upfront but never need to be replaced.

The positive wire then attaches to our CTEK box, the D250S Dual. This box is an MPPT charge controller that allows the battery to be charged by the solar panel and by the alternator while we’re driving – great on overcast days. CTEK is a Swedish company that makes some badass battery chargers for all kinds of different uses. The negative wire is also attached to the negative terminal on the box. You can definitely opt for a much simpler and cheaper charge controller if you don’t plan to incorporate your alternator.

Side note: When we bought the van, we already had a 12V lead acid marine battery in the back that had a wire running directly from the alternator that would charge while we were driving. We didn’t want to cut this power source off so that’s when we discovered the CTEK box.

Next, a thicker 4 AWG positive wire runs from the CTEK box to the positive terminal of the house battery. We’ve added a 20 A breaker in between. A 4 AWG negative wire runs from the negative terminal of the CTEK box to the negative terminal of the house battery. We’re using the single 12V lead acid marine battery we already had but will eventually upgrade to two 12V batteries. When using multiple batteries, understand series and parallel wiring. Your battery will probably be the most expensive component so picking the right battery is essential. The CTEK box is also equipped with a temperature sensor that sits on top of the battery to maintain an optimal charge.

The house battery feeds a couple different things: first, a separate positive and negative 4 AWG wire runs from the battery to the 1000w pure sine wave inverter, also from Renogy. This is probably the most important area to study before you buy; understanding the amount of power your household items use when they first start up versus when they’ve been on for a few minutes is key. Take some time to understand surge power and sine waves to figure out how hefty of an inverter you’ll need. With a 150A breaker on the positive wire, the inverter converts the DC power coming off the battery into the AC power required for household appliances. You can plug stuff in directly to the inverter or run an extension cord, like we did. When shopping for inverters, read lots of customer reviews because the fan in many cheaper inverters can be incredibly noisy. It’s not an area you want to cheap out on.

Next, a 10 AWG positive wire with a 30 A breaker runs to our fuse box, where the fuses for all of our DC-powered appliances live. For us, that’s the fridge, lights and furnace. Again, this was part of our existing rudimentary system when the alternator was hooked up directly to the house battery so that’s why the fuses are the old school glass ones.

Also, there’s a negative 10 AWG wire running from the negative terminal of the house battery to an earthing point to ground the circuit.

On the final mount of the CTEK box, a positive 10 AWG wire runs all the way to the alternator and starting battery in the front. Here, we’ve put a killswitch in between if we ever want to cut the power from the alternator and rely solely on the solar panel. And of course, there is the existing negative 10 AWG wire grounding the starting battery as well.

Finally, the battery also has thin 22 AWG positive and negative wires running to a battery monitor that allow us to see the charge percentage and how many volts it’s getting.

SO HOW MUCH DID IT ALL COST ANYWAY?

Renogy 150W Monocrystalline Solar Panel – we paid $200 *Boo, Renogy no longer makes this panel but this is basically the same one

Renogy 1000W Pure Sine Wave Inverter – we paid $180 BUT we bought ours refurbished directly from Renogy. A new one will set you back $270

CTEK D250S Dual (charge controller) – we paid $283

Battery – “free” because we already had one but expect to pay $300-500. This is the one we’re lusting over. *New battery update below

Wiring – we paid $70 (we bought the linked product from Amazon and got the rest bulk at Home Depot)

Breakers – we paid for 4 @ $13 each = $52. Using regular fuses would definitely cost less but always have a few extra on hand.

Killswitch – we paid $14

Metal beams for mounting + hardware – we paid $32 (you’ll have to go to the hardware store for these)

Mounting Z-Brackets – we paid $10

Rooftop Double Cable Entry Gland with Sealant – we paid $20

Battery Monitor – we paid $15

Cable Organization (wall mounts to keep the wiring tidy) – we paid $7

Grand total: $883

*Note that this pricing is all in US dollars because we purchased everything in the US of A.

FINAL THOUGHTS

We broke even in 6 weeks not having to pay for RV Parks. We now have so much more freedom to work from wherever we want to and not have to worry about reservations and fees. Taking the time to thoroughly research which components fit your needs and budget is well worth it. Hopefully this helps anyone looking to add a solar system to your van or RV…it’s not as scary as it may seem!

Download our visual guide here. (*Full size version with two panels here.)

Feel free to shoot us a message or leave a comment below if you have any further questions or need clarification on anything. This post is jam-packed with helpful links so click away!!