Monday, October 29, 2007

Energy from the sun!

It has been quite a while since our last (delayed) post, but that is not for lack of activity. Erin and I have been super busy finally putting the crowning touches on our electrical system, as well as trying to sew up a storm for the upcoming Holiday Market. But we finally made a breakthrough and got everything hooked up and juiced up - as Luna waits patiently out in the driveway, every tiny sun ray is generating energy! It is quite a feeling to truly be power-independent.

I have to say that at the beginning of this project, I was proud of learning such simple things as the differences between types of screws or lumber, but it was seriously a mental hurdle to now come away with a relatively competent understanding of electrical wiring and all the intricacies therein. Erin spearheaded the hard science learning and planning, and we are now blessed to have a working system in our bus, without any serious injuries along the way.

Above: our bus-wide master plan.

Below: detailed info on how the solar controller is hooked up. The solar controller switches the panels on and off depending on how charged the batteries are and does other mysterious things, too.

Our electrical gizmo "bay" which will be built into the wall under the kitchen table with a door to access it when need be.

On to technical details... The first thing we did was plan out our various AC and DC circuits and wired them into our respective 12 v. fuse block and 120 v. circuit breaker panel.

An example of some of our circuits - (DC) light to light and (AC) outlet to outlet. Library books helped us figure out how to wire the AC circuits. DC information was harder to find in print. We are going to cover all the wires with those little plastic sheath things.and paint them the same color as the ceiling (which is going to be a creamy butter color).

Our overly large but functional AC circuit breaker panel. We will try and get a picture of the wiring going on behind the scenes later. It looks pretty cool in there.

Our DC fuse block - room for more circuits if need be.

Next we installed our four 6v. batteries in their snug little box and wired them together - two in series and two in parallel to make a final output of 12 v.

This is how our battery bank is wired. We took pairs 6v batteries and wired them together in series to make 12v. Then the 2-battery units were wired together in parallel for more amperage.

One of the biggest hurdles in accomplishing this whole mess was figuring out the proper gague wires, connectors and all the other doohickeys that are used. It was hard to find concrete, applicable information for extreme novices doing such an obscure project at the library or on the internet. We also found that most of the various folks we talked to at the many electrical/RV/auto/hardware stores that we visited had divergent answers as well! We ended up contacting the specific manufacturers of our inverter, converter and solar panels to get the intended specifications. We also were able to track down a few folks at some stores who really demonstrated that they understood what we were trying to accomplish and had some awesome suggestions. (Like the people at Northwest RV Supply and Surplus and the Knecht's out on West 11th)

Anyway, after getting the batteries wired together with 4 gwa, we hooked our 1000 watt inverter in between our battery bank and our AC circuit panel. We used a heavy duty extension cord to plug into one of the AC sockets on the inverter and power our 120 v distribution panel. We took a lead from the positive terminal of the inverter and ran a 15 amp in line fuse straight to the DC fuse block and grounded it all from the negative terminal of the inverter straight to the chassis. After this was accomplished, we could actually turn on our DC lights, and plug into our AC outlets.

The inverter has a pleasant little hum when it is turned on.

Next came the final step: mounting the solar panels and wiring everything through solar charge controller. Luckily, the kind people at AM Solar in Springfield made things super simple for the DIY-er by providing clear instructions on how to wire everything together. When the first sunny day rolled around, we were up on our bus roof mounting the panels and wiring it all through the roof-top combiner box and down through the ceiling and into the charge controller. We got all the other wires hooked in and without one spark we now have power!

The two 100 watt panels basking in the Oregon shade. The combiner box with the whole down into the bus interior is underneath the right-hand panel.

The hub of it all: the solar charge controller.

Wires entering the battery box from the charge controller, inverter and engine batteries.

More holes into the floor of the bus.

We have to give serious thanks to our friends Yona and Zeke who were generous enough to come over and do a safety check and help us put the final touches on everything. It was all very exciting and quite satisfying to finally have that most crucial element complete!

We have decided to forgo the converter/charger element in our electrical system for now. We bought a huge old used 50 amp ferroresonant converter and we'll keep it around until we decide whether or not it's going to be a necessary part of our system. We didn't like the idea of a sparking, arcing box in the all-wood interior of our bus and we've started to hear there are other ways of going about charging the batteries directly with shore power without the need for a permanent box. For now the solar is meeting all of our electrical needs so we'll see how that goes.

On to the plumbing!

Monday, October 1, 2007

Battery Box!

The battery box construction, though it would seem to be a simple and unremarkable thing, was actually a super exciting and challenging endeavor. Erin designed an immensely solid box that involved salvaged angle iron, plywood, extra long and sturdy bolts and lock-nuts. We finally got a chance to test our true construction skills by sawing up metal and drilling fatty holes in the bus frame :)

We started by measuring out how much room the four batteries took up and the space we had to work with between the two L-shaped beams underneath the bus. We put it on the right side (facing the bus) directly in front of the wheel-well. We arranged it so it would be in a direct line from the solar panels and charge controller to minimize wire runs. Next we cut two strips of angle iron to be the two side supports that would hold the bottom of the long threaded rod that we would suspend the whole box from.

Meanwhile, I drilled a bunch of holes in the angle iron using our nice cobalt bit and my dad's old drill press. We cut up the 1/2" plywood sides to the box - two thicknesses for the bottom plus two strips of steel for extra security. Erin drilled a bunch of holes in the back piece for a vent. Then we mounted four pieces of angle iron to the inside bottom of the box that would hold the batteries exactly in place so they wouldn't slide around, and planned two pieces that would also run along the top sides of the batteries and be bolted down as well

Once we got the whole box screwed together, we cinched up three of the lock nuts - one underneath the box, one on top, and one that would go under the L-shaped bus beam. Then Erin sawed a square out of the side of the bus and we put a couple of hinges on it to make an outside door! We had also put a couple of hinges on the front of the box itself and a locking piece so that we can throw a pad-lock on there just in case.

Next came the tricky part - trying to hoist the massively heavy box underneath the bus and shove the long bolts perfectly into the pre-drilled holes we had made, with just two people. To say the least it was a challenge, but we got it in there and cinched down the last of the lock-nuts, the ones that will actually keep the whole box from falling out beneath us. We were quite proud once we have finally got it up there!