The First Heat Wave

Back when it was minus twenty four degrees, I complained.  Sure.  Everyone does. But I don’t think I complained very much because I knew this time was coming.   It is crazy that less than a month ago I was contemplating snow delayed travel plans and this past weekend was in the nineties.  Today, my first day back at work from a holiday, it was ninety three in our big city.  But it was never really a sunny 93, more of a hazy muggy one.

This morning when I arrived I forgot to open up the roof vent.  But, really it wouldn’t have made that much difference if I had.  About eleven it was pouring.  The roof vent would have closed and the fan shut off when it sensed the rain.  Then it cleared enough so I could grab some lunch before it rained lightly again.  By four it had stopped raining and cleared to a haze but the van was in the shadow of our office building.   I popped out and opened up the roof vent.  At that point the ambient air temperature was still about ninety.  The van was actually cooler inside than the outside temperature.  I was temped to just leave it sealed up but then in the end, opened it and had the fan blowing at 85%.

The square cut out of the poly-iso foam
to expose the plywood underneath. 

About six thirty I was contemplating my dinner options.  Everything I brought today was still frozen so I was contemplating a walk.  That got dashed when I stood from the cube farm to check the weather.  Not good.  I came straight out to the van it was already sprinkling when I arrived.  Inside, it was warm but really not bad.

I have the ability, via some temperature probes and some little process control computers (that I will get to in a later post),  to know a lot more about my environment now.  I just finished heating some dinner in the microwave and it is eight thirty in the evening.  It has been off and on raining since I came out.  Prior to that, the cabin temperature of the van was eighty degrees.  Cooking raised that temperature by two degrees.  But, the outside temperature is a wet seventy.  If it ever stops raining I am going to be able to kick on my roof vent and drop my inside temperature right down.

If it would only stop raining…

Here is the tape tab I attached to the
square of insulation.  This will make it easy
to pull the insulation out without damage.

This weekend was a hot one as well.  Record temperatures and muggy.  Despite that, I had a job to do.  The one I had driven The BV home to perform.    As I mentioned in my last post, or to condense here; 1) I have to be able to access the tops of the batteries four times a year.  I have to visually inspect the fluid level and test the specific gravity.  2)The buggers are heavy, and for energy efficiency, on as short of wires as possible.  Their mobility was both limited and difficult.  Therefore some type of top access panel needed to be constructed.

I pulled the mattress out and brought it inside the house. -This one step was the bulk of why the job was happening at home.  The single most valuable investment in the entire project, I wanted it well out of harms way.

Underneath the mattress I have the panels which will become my under-bed vent system.  Until such time, this is just the most convenient place to store them.  Under that I have one inch of poly-iso foam insulation.  Then, three quarters of an inch of plywood.

Starting out was really the difficult part.  I had to figure out where the batteries sat and then transfer those measurements up on to the insulation of the bed.  I cut a slightly oversized hole in the insulation.  That part was difficult because the utility knife I have only cuts a little over 3/4” deep.  I ended up using a ginsue knife from my cooking drawer to make the final 1/4” cut.  My friend Craigie has one of those nice extendable blade utility knives.  That would really be the way to go.

Here is the lip that will hold the access
panel door in place.  This is only glued in.
I could have shot some brads in as well
but that would have required battery removal.

When cutting this foam to cut a block out, you have to cut a relief.  That’s a second cut, about an eighth of an inch outside your primary cut on two adjacent sides.  When I dug out this relief, the inset cut square of insulation could be lifted up out of the hole.  I wrapped the edges of these squares with wide metal foil tap. I also put foil tape tabs at each end of the squares.  These tabs will fold up over the top but make it easy to pull out the foam square in the future.

Now it became serious.  It was very, very important to not cut *any* wires while cutting the plywood.  I set my circular saw depth to barely cut though.  But then I also checked it out closely underneath.  I had one screw in wire clip holding one of the wires coming from the solar charge controller.  That clip was about in the middle of my proposed door.  I removed it.  That allowed that wire to drop out of likely saw blade harms way.  At the back I have a second shunt on the line going/coming from the inverter/charger.  I hope to some day record my high voltage appliance electrical usage separately from my twelve volt.  —Data geek, remember?

"We're in a tight spot!"

Once I had the foam out, the wires out of the way and the saw depth set, I was ready to cut.  And I did.  For almost two inches.   Ah yes.  Old house.  I used the saw to cut some lath and plaster in its last use.  I had to divert to the hardware store for a new blade.  The circular saw cutting was really fairly minor.  Only a few inches on each side, but it is way easier to control your depth of cut than a jig saw would be. 

I undercut the corners just a bit.  Leaving the square hanging.  Then, after a double check to again make sure no wires would be affected, I used a portable jigsaw to cut the final little bit in the  corners.  Once I had the doors cut out I used them to trace an oversized hollow square out of quarter inch plywood.  I made it a little over an inch wider on three sides, a touch narrower at the back because it was butting up to the divider wall between the battery compartment and the rear storage, behind the drawers.

You can just see the battery cap.

Once cut out, I glued it in place under the bed —Uh, that is after another trip to the hardware store.  Any project worth doing requires at least two trips to the hardware store.  My glue must have frozen in the great New Years freeze-up.  Back when I ran out of propane over Christmas break.  Back from the store with the glue, I clamped it all in place.  It was a tough job getting all those clips and clamps around in such a small space.

Of course I forgot to take a picture of the finished product.  But, in all of this I never did check the fluid levels so I will have to be in there again in a couple of weeks.  I will get some pictures of what is involved in the process.

The two battery access panels out and the glue-in lip
in place with clamps holding them.

It was an exhausting day though.  Temperatures in the nineties and lots and lots of climbing in and out of the van to check cuts, clearances, etc.  I think I drank about ninety ounces of water and sweated it all back off.  Plus, I used it as a juicy rationalization for consuming about half a jar of kalamata olives later that night.  ...I had to replenish my salt, didn't I? :-)

It is currently a little after eleven pm.  It has been raining fairly steadily (excepting for the periods where it was pouring) since a little after six thirty.  Tomorrow night, when we have forecast more of the same, I am going to park on higher ground.

Battery Access Version 2.0.0

I wrote this a couple of weeks ago but then never pushed publish.  It is crazy how much the weather has changed since I wrote it....  Back at that time I was saying "Yeah, remember that snow storm in the forecast this past weekend?  Six inches of fresh snow? Never mind about that, it was almost seventy today." Tonight I am sitting in a bar with an outdoor patio.  It is purely crazy to be living somewhere you can be drinking beer in a t-shirt looking at a snowbank from the bar parking lot plowing that must be twelve feet tall.  Purely crazy.

I have come to the conclusion I have made another mistake.  This one though, this one is going to be a tricky one.  You see, The Wife was the one who said I should build it a different way.  And she’s the very devil when it comes to matters of me being wrong.  In my defense though, I have some sound scientific principles behind the decision I made.  If I was, say twenty seven, I wouldn’t even recognize the problem I have.  Sadly, I am not.

Here’s the deal.  To maintain my cabin batteries in top condition I need to check their fluid level in each cell of the battery.  Additionally, in my case since I had that wiring problem, I really should be checking the specific gravity of the fluid each time with a battery testing hydrometer.  This should happen four times a year.  Each battery weighs 62 pounds.

The battery tucked in under the bed.

What my plan had been was to place the batteries on some polypropylene squares and slide them out each time I needed to.  I figured some 3/8” plastic with some rounded corners would not bend with the weight and slide around pretty easy on the steel of the van floor.  I hadn’t quite figured out how to keep these sixty two pound bricks from sliding around all the rest of the time.  --Like when I am driving down the road and take a corner a little too fast.  I was hoping to work that all out once it had become a problem.  But when I was planning these plans I also hadn’t actually seen a van up close yet.  Once I did, I immediately saw why these plastic slides wouldn't really work.  The van floor isn’t the smooth waffle around the outside parameter like it is in the middle.  It has seams with rubber calk coatings.  No way my plastic slides were going to work in this environment. They would stick to the calk.

I ended up just putting the batteries right on the floor.  They are pretty solid there.  Even though they are not attached down at all, they still don’t slide around.  They are still movable if I need to drag them out like I did a couple of months back for the re-wiring job.

Snow storm that week, ninety this week.

Here’s where The Wife got involved.  She suggested I build battery boxes with access down through the bed.  She suggest I make an access panel I could get at with the mattress out.  The problem with that idea from a safety perspective is when you charge lead acid batteries and particularly when you do what is called equalizing them.  The equalizing process charges them at a high voltage.  The purpose is to remove a film which builds up on the lead plates. The batteries actually boil during this process.  In this case, the steam that is coming out of the pot as it were is pure hydrogen gas.

Remember high school chemistry and the big chart on the wall?  Hydrogen occupies the upper left square.  The significance is this gas has little tiny molecules and it can seep into the smallest of cracks.  Propane gas is both significant larger in molecule size and it is heavier than air.  Any propane I leak in the back of the van will escape out the floor.  Hydrogen on the other hand is lighter than air so it will try to work its way up into the cabin.  Let me switch you from Chemistry to History.  Remember the Hindenburg?

So it was for these scientific reasons along with my opinion of the labor of pulling the mattress out every three months just so I could test the batteries seemed like too much work. I ended up just pushing the batteries back in place and told myself I would pull them out as needed.  The next eight months passed real quick as I shuddered each time I thought about doing the fluid level check.  The batteries were not critically low when I finally did get around to it but they certainly were not great either.

I have come to the realization I am going to have to build the hatch through the bed and confront the gas leakage with some weatherstripping.

At the same time I have come up with an idea for reducing the under mattress condensation problem. I covered this a few posts back with a long list of my possible options.  What I settled on was building something myself.  But since that time my design has changed.  I was thinking of using some strips of 3/4” plywood as spacers, then some 1/4” plywood on top with holes drilled in it.  Then, the mattress on top.  I was never really happy with this idea.  I felt like the mattress would only really dry where the holes were.  I just wasn’t so sure about the area an inch away from the hole.  I was concerned I would still have mold growth.

My new design puts the thin plywood on the bottom.  I would still use the same spacers but stapled to the spacers I would stretch some #4 (1/4”) hardware cloth.  This design would allow airflow almost everywhere.  It will be strong enough to not sag and let the foam block the channels.  I think this will work perfect.  Likely the building of this setup will be one of the next blog posts.