Sexy solar and electrical!

HI! Help me please!
I am looking for advice on adding solar to my existing system. I currently have 2 100 amp hour deep cycle batteries that charge off of my vehicle with a battery isolator. These batteries were in the bus when I bought it (it was partially converted) and I was told they were sufficient to run the:

  • d2 espar heater
    -LED lights
  • reverse camera
    -and water pump.
    I have since put in a Dometic Coolmatic CR-1065U/F 2.3 CU. FT. 12/24 Volt DC & 110/220 Volt AC Built-in Refrigerator and I would like to add solar to ensure that my batteries are charged enough all the time to run this fridge. I also have a 100 watt inverter for charging my laptop and phone but and thinking of getting a large one.

So what size solar panels do I need? Charge controller? is it better to get a kit or just add on to my set up? Is it easier to instal panels or glue flexible sheets to the roof?

I am feeling a little overwhelmed in a sea of information and any advice would be greatly appreciated!!!

Thank you in advance!!!


Greetings & Welcome!

Let’s start at the beginning, what’s your location, and where do you plan on traveling, and how often do you plan on driving, and how far.

Those types of fridges are power hogs, and they generate heat inside the van, for solar panels to work, you must park in the sun, and that will turn your van into an oven, causing the fridge to run more and use more power.

If you’re driving enough, the isolator should be capable of charging your house batteries, and if you skip solar and park in the shade, you, your van, and your fridge will be much happier. If you’re not driving enough, a cheap generator is usually a far better choice than solar, and isn’t dependent on the weather.

While solar get’s hyped a lot, because people get paid big money to hype it, most people later regret it and wind up using a generator anyway. There’s nothing sexy about solar, it kills batteries prematurely, and is frequently a money pit.


"Be the reason someone smiles today!" ~ Van_Dweller

Hello! Thank you for this awesome information! I am actually building my bus to be more of a “mountain chalet” as I am in the mountains of Colorado and it will be COLD, albeit sunny. I also have a honda 2000 generator for camping but when this is my full time home I don’t want to incorporate the generator into my set up. I plan on trying to park incognito often and a noisy generator would give me away instantly.

I will be parked in the sun often and I am not sure if I will be driving quite enough to charge my batteries so that is why I thought a bit of solar would contribute nicely.

I really appreciate your input but I am still looking for advice on solar set ups.

Happy Travels!


Oh, okay… You actually have a bus, not just a VW Bus?

That changes everything, because you have a lot more roof space, and interior space and carrying capacity.

I would add another 200 amps worth of batteries for 400 amps total, and then 1200 watts worth of solar panels. You want to go with rigid panels, the flexible ones don’t hold up as well. With that size of system, you’ll want an mppt controller. (More efficient)

I’m not familiar with their kits, so can’t advise on that, but Renogy seems to have a good reputation. If you go with 48v panels, the wiring to your controller can be smaller, because the amp load they will need to carry will be less. You want to size your wires for both the voltage and the amps they will be carrying, then go a little bigger just to be safe. There are charts online.

I would try to get 12v car cords for your laptop and phone, because inverters are terribly inefficient, and you never want to leave an inverter on when it’s not in use. Then on the rare occasion that you need shore power, you could fire up the generator. I added a scooter muffler to mine, and it’s so quiet you can’t hardly hear it.

Your heater may not cut it at higher elevations, or for a bus, but a 23k BTU portable kerosene heater keeps me toasty down to -60°f. Then I also have 12v heating/cooling blankets and seat cushions that can really make a difference too. Add a swamp cooler and you can be ready for anything Mother Nature throws at you.


"I can live like a king because I work like a dog." ~ An anonymous vandweller

Thank you for your info!!1

I have a SHORT bus. SO there is no way that I could fit 1200 watts of solar on top nor do I need that much. I was looking into 300 watts max. I will look into Renolgy. Thank you again for your help!

Safe Travels!


According to this solar efficiency chart, which is the most accurate I’ve found, 300 watts isn’t going to be enough for that size battery bank.

I can tell you from experience, with 300 watts of solar, it was very rare that they would top off my 100 ah battery in a day, and that was during the summer.

I finally have just given up on solar, and charge my house battery mainly while driving. Between my 100ah deep cycle house battery, and an identical starter battery, each battery will power my van for a week before the battery protector will cut them off to prevent over discharging them. That still leaves plenty of power in my starting battery to start my rig.

If I’m stationary for more than 2 weeks, (very rare) then I’ll charge my batteries using a $99 gas generator combined with a $29 battery charger. All in it is far cheaper than solar, and also much more reliable. Now, instead of my batteries lasting 6-9 months, they last 5-7 years.


"I can live like a king because I work like a dog." ~ An anonymous vandweller

I am installing solar in addition to the smart isolator battery charger that is already charging my batteries from driving. I agree that 300 watts of solar alone might not be enough but I’m hoping that using both sources of power will be.


Okay, the isolator will make all the difference in the world. My isolator provides all of my power needs 99% of the time.


"I can live like a king because I work like a dog." ~ An anonymous vandweller