Solar Power!

One thing I was absolutely sure we had to get some experience with was solar for the bus.  I watched a lot of youtube videos of "survival bus" type hookups, but everyone I saw used the heavy poly-crystalline type panels which I knew were heavy and possibly prone to cracking.  So the search went towards flexible panels, and I was lucky enough to find these amazing strips made by Uni-Solar, for our install we used the PVL-68 which pumped out 68 watts at 12V at peak.  This turns out to be about 12 amps of current at max flow!  The greatest moment was to know that the 9ft length would fit on the roof of the bus::

Best part about these panels is that they are super-easy to install, because they have a super tar adhesive that you literally just peel back this cover, and they stick like they'll never come off.  We made some marks to make sure they were straight, and stuck them on.  Total installation time about 30 minutes!  Notice the wiring was left open until later...

Next part was getting some decent reserve capacity for the aux batteries.  The day before we left I bought another deep cycle marine battery to match the one we had purchased a year before.  I had to cut out the spare tire well (not used for the spare on the camp mobile model) so I could align the two deep cycle batts side by side.  Crude cutting, but remember I was doing this in a camp site with modest hand tools!

Here are the two batts strapped in as best as possible.  12K miles and they didn't shift much :)  I actually mounted these batteries in at a campsite in NY before heading west, so technically we were on the road at that point and limited in craftmanship, material, and time.

Here's a shot of my more or less finished exterior wiring of the panels, using couplers from Win-Solar LLC, which had the best prices.  Here we are at an RV park in Wyoming just before it started raining at about noon.

I later locked down the wiring a bit better with zip ties and cleaned up the master fuses for the panels.  I'm very satisfied with how the wiring has handled the opening and closing of the pop top, it's found a way to not be crimped or pinched ever, after many campings!

And here is the inner workings of the system:  The controller and load distribution.  I actually wired this in at Burning man on an idle afternoon because we had great solar energy (being the desert and clear) and needed the fridge to get up and running.  Basically it required just making sure the wiring was solid, not crimped or pinched, and fused where it needed to be.  You can see in this pic the wires coming from the panels (top left), going into the controller (crimped with smaller gauge wire for connection), a fused output to the batteries for charging (and power) and a fused output to a fuse block where each load could be individually fused.  Here also we have a 1200W continuous inverter:  With enough battery power we can actually power a microwave or maybe even an air conditioner.  Notice the power lead going to the hookup with the fridge connection (top right).

Here is the 15 amp MPPT solar controller I ordered direct from Hong Kong on eBay for $40.  So far it's working great and as I understand the MPPT (microprocessor controlled) gives better efficiency compared to analog controllers that are even cheaper.  For the 136W array on the roof, this little controller is definitely sufficient.  Notice the easy to define hookups for panels, battery, and load.  This controller is fine for small loads like the fridge or maybe a lamp array, but is not suited for the inverter which requires a direct connection to the battery.

In terms of usability, generally the usage went as follows:  The aux batteries have no connection to the alternator (vehicle charging system) yet because it will require a much more intricate wiring system (relays to switch from solar to alt when ignition is on), so this is to say the solar system as is is totally independent from the starting/charging system of the vehicle. This is to say that the aux deep cycle batteries only received power from the sun (as did the fridge, being the only load hooked up full time).  The controller is setup to cut off the power to the load when the battery voltage would drop below 10.5 volts (to preserve the cycle life of the batteries), so this would generally kill the fridge at about 10 PM, after about 3 hours of running purely on the batteries with no solar supplement.  By the time we would wake up in the morning (about 10 AM) the fridge was usually on, the solar panels having charged the batteries enough to allow the controller to turn back on the  loads.  The fridge would then run all day, and the batteries would generally be charged enough for 3 hours of independent 5 amp (?) draw.  On cloudy or rainy days the fridge might cycle on and off a few times, but those days were relatively cooler.  The sunny days that would heat the cabin to over 90 F were the days that we really needed the fridge, and it performed beautifully.  Granted this fridge does not generate ice, but not ever having to change a propane tank and having it run all day regardless of whether the car was being driven was a great success in a first prototype in free energy.

We received a lot of inquires and comments from other RVers who hadn't seen these amorphous solar panels before (fully flexible).  For the $200 cost I think they are very exciting, especially for a residential installation.  They are easy to install, safe and convenient especially using industry standard quick-connect weatherproof plugs.  I'm looking forward to building a larger array that could be used with a grid-tie inverter for a residential setup.  COLD DRINKS FROM THE SUN, FREE ENERGY BRA!