Station Wagon Solar Roof and Solar Sub- Self Sufficient Sonic Splendor

Toyota has been advertising the “Solar Roof” option for the new 2010 Prius- it’s basically a solar module integrated into the roof panel that runs the cabin ventilation fan on hot and sunny days. Simple enough- but what they didn’t tell you is that you can have a solar roof on any car- obviously!


I set this system up for my Northwest roadtrip, as previously described. It worked like a charm, supplying me with laptop charge and ample stereo bass all 2300 miles of my trip. What’s this about subs and bass exactly?

IMG_8687One of the prime objectives of the system was to power up my subwoofer system- because what’s a roadtrip without a subwoofer? You may be thinking to yourself, WTF? So let’s get this straight. I mounted an 80watt polycrystaline PV panel to the roof of my station wagon. I ran the power to a charge controller and 90AH SLA battery pack behind the drivers seat. And with the resulting charge I ran a small inverter and a subwoofer amplifier.

'90s Japanese midsize wagons aplenty

'90s Japanese midsize wagons aplenty

Simple enough- and in all seriousness, it worked really well. Here’s the details:

The module is an 80 watt Photowatt module I purchased several years ago and borrowed from my roof.

IMG_8695It’s anchored to the Camry’s factory-installed roof rails by way of 2×2 lumber, U bolts and plastic tube

IMG_8696Note to self- beware that the distance between the rails on the Camry gets bigger toward the front of the car!

12GA landscape-lighting cable is run in through the rear hatch- I’ve found that landscape lighting cable is widely avaiable and not too expensive, as well as water and sunlight resistant.

IMG_8697IMG_8699The cable is run forward to the driver side rear footwell

IMG_8698From there, the charge controller and batteries are hooked up, as well as the loads.IMG_8276I used the parts I had on hand- 2x  tired old PowerSonic batteries, a BZ Products M20 charge controller. The terminals are insulated with tape, I neglected to add fuses aside from the charge controller’s internal fuses- not a good idea, but I was lucky and was spared any disasters during my trip.

A small mod-sine inverter was sufficient to charge my laptop while I was camping. I made its leads long enough to move around the front seat area.

IMG_8688I put the sub amp under the passenger seat

IMG_8691And used this sweet pushbutton I scavenged from an old junked BMW to activate the amp


There you have it- for two weeks this system kept me supplied with charging power and sweet tunes. It was a no-brainer project for me since I already had all the equipment, but I could see something like this being very worthwile for the avid car-camper. It’s like how many RV people put up solar panels- why should they have all the fun?

If you’re interested in putting something like this together, there are a million different ways you could go about it- roof racks, solar panels, charge controllers, batteries- but here are some ideas of where to start.

PV Panels:

Charge Controller

Battery pack

Make sure all your wires are appropriately sized (12GA min, 10 or 8GA OK) and that you use ample fusing. For systems this small an inline ATC fuseholder is generally sufficient. “Car Stereo” style fuseholders are also a good option, also easy to find locally and with higher current capacity. There is some benefit to using a fuse block, but this is one of the areas where it is easy to quickly stray from the KISS (keep it simple stupid) ideal of the project.

If you crimp terminals crimp them tight- you should be able to break the wire before it comes out of the crimp. Landscape lighting wire and ATC fuseholders/fuses can be found at your local hardware store. It’s no problem to attach an inverter to the system, or a cigarette lighter receptacle (auto parts store) for other types of chargers. A 30 amp system fuse will support a 350 watt load.

Hope you find this interesting or inspiring. I sure appreciated my purely solar powered sub tones all the way up and down the West Coast.

Posted on September 29, 2009 at 9:53 pm by Henry · Permalink
In: Life and Times, Little Fixes, Renewable Energy System

Leave a Reply