Thanks Stuffz.

House battery frame and venting, Post 3

In the last post I showed a copper bolt attached to the van floor that was going to be used as a grounding point. A couple of people pointed out that the bolt should also be grounded to the frame. That made sense so in the last couple of days took care of it. And surprise, surprise. I have pictures!

Ordered a two foot length of 1 inch wide flexible grounding strap from McMaster-Carr. It's $4.80 per foot. Listed as comparable to 1 AWG. It's probably overkill but at that price, why not.


Once more unto the breach, dear friends. It's back under the van I go.
You can see the copper bolt on the left. I want the grounding strap to run from it to...


...the frame beam here on the right. The bolt end won't be a problem but the frame end will. One problem is the emergency brake cables. Nothing I add should interfere with them.


Another problem is that the gas tank is right up close to the other side of the frame beam.


And on the inside of the beam are vent lines that run to the emissions canister. Between the vent lines and the gas tank It's impossible to get my hand up behind the frame beam to do any work.

Need an anchor point for the frame end of the grounding strap. With the gas tank and vent line in the way, drilling a new hole is out of the question. Have to make use of one of the holes already in place.

This picture is looking straight up from under the van. The best candidate seems to be the slot you can see to the right of the painted over bolt.


By the way, thought of using the painted over bolt but once I got to working on it found it so rusted it would probably shear off before coming loose. Then I'd have a new problem so let it be.

The slot is just big enough, and I do mean just, to get a small length of angle iron through. Use the angle iron as backing for a nut. Slide it through the slot then rotate 90 degrees. This will hold the nut in place. That solves the problem of not being able to get my hand back there. Cut and drill the angle iron then weld on a nut for a 3/8" bolt.


Prep the ends of the grounding strap. Cut out a strip from a piece of .0162" thick copper sheet I had on hand.


Wrap the copper around the strap then crimp the end.


Fold over the crimp.


Apply flux to the end of the strap where it enters the copper end. Use a propane torch and solder to seal where the two meet.


Drill a hole for the bolt and do a test fit under the van before trimming the strap length. Then do the other end.


Want to make sure there is good electrical contract to the frame so need to do some work around the slot. No room to get my usual favorite metal cleaning tool, angle grinder with wire wheel, up in there so used a flat ******* file instead. And yes, it's really called that.


Took some upside down elbow grease but I got all the old undercoating and rustproofing from around the part of the slot that the strap will contact.

Next used sandpaper to get a clean surface. After that it was as simple as bolting each end in place.




OK, that last line was a lie. When maneuvering the angle iron with the welded on nut into place it fell in between the beam and the vent lines. Much cursing ensued. Luckily one of my tools is a magnet mounted on the end of a goose-neck style rod. Even with that it took at least 15 minutes to fish it out.

continued

 

House battery frame and venting, Post 4

With the frame for the batteries done, cut a couple rectangles from a block of nylon.


Drill a hole in the nylon blocks and use them as hold downs for the batteries. I used nylon since it is nonconducting.


Upgrade the battery caps to Water Miser Vent Caps. $3.77 each. The caps are supposed to reduce the frequency of adding water to the cells along with some other features. One advantage is they have a flip top so don't have to worry about taking the caps on and off to check fluid levels.


Install the batteries and sofa-bed then take the van out for a late fall camping trip.


The wiring in this photo is of a temporary nature. I had the inverter and furnace running off the batteries without any charging wiring hooked up. Since I wasn't charging the batteries I didn't have to worry about venting.


The advantage of four batteries is that they still read 12+ volts at the end of the weekend without charging.

Back at the garage workshop build a wooden safety block for the top of the empty frame.


With those two bolts extending upward from the battery frame it would be just like me to stumble while working in the van and impale myself on them. The wooden top should prevent that. The impaling not the stumbling.


Next up build a plexiglass lid for the top of the batteries.


I built this using the same methods as when I made the lid for the previous wooden battery box.


The lid will collect for venting the hydrogen gas produced when the batteries are charging.

continued-

 

Wow what a great read!

 

Thanks Fuli.

House battery frame and venting, Post 5

Need to add vent fans to the lid. Even though hydrogen is lighter than air and should naturally flow out if the vent outlet is higher than the inlet I want to give it some assistance. The amount of hydrogen gas produced by a charging battery at any one time is fairly small so I won't have to move a great deal of air. I'll be using small 12 volt "muffin" fans. This is a induction type fan so it has no brushes that might produce electrical sparks like a regular motor.

I'll make the fan enclosure from some scrap pieces of plexiglass. Create a mock up from cardboard first.


Then use some smoking matches to see if it will really move air through a hose. It does.


Start work on the plexiglass version. As an added safety feature stack wire mesh to create a flame arrestor between the fans and the inside of the vent lid.


Countersink the edges of the hole then sandwich the wire mesh between two plexiglass pieces. The countersinking allows the two pieces to be in contact over their length with the wire between. This will be the base of the fan enclosure.


Start cutting and drilling plexiglass pieces as I come up with a design.


While most of the enclosure is glued together I want to be able to replace the fans if needed.


Drill and countersink holes for nuts.




Starting to take shape.


Added small rectangular pieces to the inside to keep the fans in place.


Use a bead of silicone around the edges of the fans to increase air flow. Then do the same to the edges where the enclosure screws together.


Completed.


Hook it up to a power supply to check that the fans run and I didn't gum them up.


Attach a length of hose and see if it will move some air.


It does. It will almost blow out a lit match.


Figure out where to position it on the lid.




Add connectors to clean up the wires.


Use a bead of silicone where the fan will bolt to the vent lid.


Here's the view from inside the lid looking into the fan enclosure before I cleaned out the excess silicone. Am I the only one who thinks this looks like a jellyfish?




This is the original vent lid I made for the first battery box. I'm about to use a hacksaw to remove the bungee cord hold downs from the lid ends.


Success.


Here they are attached to the new lid.


continued -

On a different note this is what I've been working on today. The kitchen cabinet is starting to take shape.

 

for the battery box, my father has an old dodge Royal popup conversion van and it has a single "house battery" in a simple container with about a 1" flexible hose to a side outlet vent. only thing different then what you have is that it is sunk about 3/4 of the way into the floor of the van.

I unfortunately do not have a picture of the insides but this is what it looks on the outside.

in the picture from left to right is power hookup (15amp), city water connection, battery box vent. click for full size.

 

House battery frame and venting, Post 6

With the vent fan enclosure done next up is the vent outlet. Here's what I bought to be the outlet on the side of the van. It came from a online marine store. It fits a 5/8" ID hose.


First decide where I want to mount it on the side of the van. It has to be higher than the level of the batteries but not too much higher to keep the hose run as short as possible. It's a trade off. It also has to be where the inside of the outer "skin" of the van can be reached so I can tighten the nut on the vent fitting.

Here's a picture of the inside of the van shortly after I bought it. Look just above and to the right of the fuel intake "hump". There is a roughly oval shaped indentation on the inside metal framework. That's the area I'm aiming for.


Here's that same area with the insulation in place. I've already drilled a pilot hole in the location I picked.


The view from the outside of the van. Having cut and drilled so many times on this van already it shouldn't be that big a deal putting another hole in the side but there's still plenty of trepidation before starting the drill.


Use the hole saw sized for the vent fitting and drill through the van.


On the inside of the van I'd cut the insulation before drilling but it was still in the way.


Perfect use for a couple binder clips.


Need to drill a hole on the inside metal framework layer that will allow me to work on the vent nut so size the hole saw to the nut.


Mistake. I should have used the pilot hole as a guide for the larger inside hole before drilling through the outer skin. Without the pilot hole to keep the drill centered I tried to hold the drill steady. The scratches in the metal show I wasn't totally successful at keeping it centered.


Here's the fitting in place and tightened down. There is enough room between the fitting and the edges of the hole in the metal framework to work needle-nosed pliers. In this picture the scratches have already been painted over.


The view from outside. I used silicone II on the hole edges before tightening to try and keep it watertight.


The vent hose attached to the inside of the vent fitting. The green hose in this picture has been changed out for heater hose which has a thicker wall and is less apt to kink.


The vent hose attached to the fan enclosure on the vent lid. In this picture you can see how the top of the lid is angled so the hydrogen will rise towards the fan enclosure end.




Here's an example of serendipity. I originally was going to have the bungee hold downs on each end of the lid but the fit is too tight between this end and the sofa-bed end. So moved the hold-down to the front of the lid at that corner. Started thinking about how to create an attachment point when I noticed my far less than perfect welding on the battery frame had created a little spur. The hold down hook fits it perfectly.


continued -

 

Computer axial/propeller fans have low static pressure. They move lots of air when under low resistance. If you want to, you can later redo the box using computer 'blower' style fans. They are able to build quite a bit more pressure, and you would only need one to make significant airflow.

Amazon.com: Genuine Dell 9G180 Blower Fan for OptiPlex GX260, GX270, GX60, GX240 and Dimension 4500C, 4600C. For small form factor and small desktop cases, not for towers. Identical fan models JMC/Datech Model DB9733-12HBTL DC 12V 1.35A and NMB Mineb

I used these types of fans when I built my computer controlled cooker. I ended up having to implement PWM because one could blow the fire out of control, even when restricted down to 3/4 inches. I actually melted the steel grating.

 

That's a good suggestion 95e150CW. I hadn't thought of using the blower style fan. I always call then squirrel cage fans. One reason I used two muffin fans was to have backup if one should fail.

 

House battery frame and venting, Post 7

After completing the venting lid with it's exhaust hose and enclosed fans there was the question about how to control the fans. I didn't want the fans running all the time since they would just drain the battery. If my only charging system was the alternator then I could power them from the running van but I'm going to have solar so that wasn't the answer. How about having the fans run when the batteries were above a certain voltage that would show they were being charged. That wouldn't work either since the resting voltage of the batteries will probably change as they age and anyway I'm not sure of the voltage level put out by the solar charger and how it will fluctuate with the sun.

I'm no expert on electronics but I have dabbled in them before so I went to Digikey and started searching around for something that might be used with a charging battery. I found the Maxim MAX4376. If I was reading it's datasheet correctly it might work. So ordered a couple.

Ran into the first problem. Here is a MAX4376 sitting on a penny. It's a really small surface component chip. Never messed with these before. Don't think I'll be able to solder on something that small.


So started searching online. Found a way to solder something this small. It involves solder paste and a electric skillet. So order some solder paste. The paste comes shipped with a ice pack to keep it cold so you store it in the fridge.

Also ordered a small circuit board that is made for this style chip. Put the paste on the circuit board pads then place the chip legs on top of the paste.


I used a dental pick to clean off the excess paste after taking the picture.

Next get an old electric skillet.


The paste has a specific temperature versus time profile you're supposed to follow. Took me two tries to get it right.


It works. Here's the chip soldered into place.


The circuit board is big enough for me to solder pins through the eight holes and use on a breadboard.


Here is my test rig. I have both a load on the battery and a charger connected.


I've got the chip mounted on a breadboard and connected to the battery via a sensing resistor as recommended in the datasheet.


When the battery is under load but not charging the MAX4376 outputs a signal of .008 volts.

When charging the signal jumps to .021 volts. This value changes as the current into the battery changes. The signal voltage range can be changed with a different sensing resistor.


OK now that I have these value what do I do with them. Well I always wanted to learn about microcontrollers so these seems as good a time as any.

Here's the microcontroller I decided to learn on. It's an Atmel ATMEGA168P-20PU. A microcontroller is like a limited function computer. So a computer for $4.85 is a pretty good deal.


The low price is the good news. What's the bad news? The fact that I knew next to nothing on the subject of microcontrollers. At the beginning of the battery venting project I talked about hitting a slow patch. Well this is it. I had to learn a new whole subject. Here is a picture of all the manuals/info/tutorials I downloaded off the internet and printed.


I won't say I've read everything in this stack but I've read most of it. And some of it more than once. This took weeks and weeks. I won't go into much detail about how microcontrollers work since this post is already pretty boring by now. Basically you write a computer program and load it into the microcontroller which tells it what to do then test it. If it doesn't work like expected you change the program and load it into the microcontroller again and see if it works. It can be very tedious so patience is required.

I'm writing the program in assembler language which is a type of computer code. I had a class in it once a long long time ago, back when dinosaurs ruled the earth, so that helped a little. By the way if you've seen the first "Terminator" movie you've seen assembler code. It's what scrolling up the screen when you see the world through the Terminators eyes. " Hey, buddy. You got a dead cat in there, or what?"

So I built a circuit on the breadboard that includes the microcontroller.


Add it to the rig and start testing it. After much work I got it to do what I want.


Here's a simplified version of what the microcontroller does in this setup.
Every 30 seconds check the output from the MAX4376 chip. Decide if the battery is charging. If it is then make sure the fans are on and functioning OK. Sound an alarm if there is a fan problem. When the battery stops charging run the fans for 5 more minutes so to be sure to purge any gas from the vent lid.

There's more to it than that but if anyone is interested in the gritty details they can PM me. If this one application was the only use I had for microcontrollers then this would have been overkill for just the vent fans but there are several different projects I have in mind. This just gave me a good excuse to finally buckle down and tackle the subject.

Haven't build the final version of the circuit board that incorporates everything yet but I'm far enough along to be sure I can get it done. It won't be needed until I can get the house batteries charging system in place. So I'll stop posting on the battery venting project until then. Next posting I start on something else.

 

I love microcontrollers! I use them all the time. One circuit I built prevents the ABS and Transmission from freaking out about the rear axle ratio change, but still lets the (secondary) PSOM display the speed correctly.

One thing you may wish to consider later is the possibility of using an MSP430 or an Arduino. They are better targeted to one shot/prototype projects. The arduino boot loader runs on atmel chips, and lets you use a very simple language to perform very complex tasks, such as talking to serial or parallel LCD panel with 4 commands, scan button inputs, read analog data, etc. If you are building a mass consumer product, then programming to bare metal on the microcontroller makes sense.

 

Now this thread is getting even more interesting.

Electronics -- I suspect WVVan ain't stopping with the battery vent.

 

BFD (Big Flooring Deal), Post 1

Putting down the floor and securing it in place is for me a big deal since it signals the end of one phase of the van conversion. Up till now I've been able to pull up the flooring whenever needed to work on whatever new project I dreamed up. It's just been laying in place. To start adding cabinets, building up so to speak, I've got to decide that there isn't any more reasons for the floor to come up. So I've got to commit to the final design. That's why this is a BFD.

But of course there a couple of last minute changes I want to make first.

Here Tiger is pointing out one of the problems that need fixed. There is a floor seam that runs from the middle of the battery frame towards the side door. The seam is in the middle of the door opening and anchoring the ends could be a problem.


When standing outside looking into the side door this is the right floor piece...


And this is the left.


Get a new sheet of plywood (11/32") and using the other two pieces as guides cut it so the seam will now lie to the left of the fuel inlet hump. The new sheet doesn't cover the same width as the first two flooring pieces so part of the left piece is reused. Now it's a solid sheet of plywood at the side step edge.


As you can see in the previous photo I'm sealing the plywood before securing it to the floor. Here's what I'm using. The only reason I'm using this particular stain is because I already had this gallon on hand. It did the job OK. Two coats, top and bottom.


Here's comes the hardest part of this project. The basement opening.


In using the basement day to day I've found the opening isn't large enough to easily allow the passage of a body. Sorry did I say body. I meant sack of potatoes. Yeah, a sack of potatoes. And it's even harder if that sack of potatoes is struggling.

Just kidding. When creating the opening for the basement I thought the widest part should run side to side. Having used it for a while I'm thinking that having the widest part run front to back matches better with the center aisle layout of the van. It wasn't the work of changing the opening that bothered me but the fact of redoing something that was working just fine. Also I'd have to trash the custom built hatchway door and frame since it wouldn't fit the new opening. Had a long debate with myself over this one since it was either change it now or forget about it.

What finally won me over to the change was the need to weld the floor to fix the earlier cut. I'd never welded on the van itself before so this would be something new.

How it looks after enlarging the basement opening.


I'll weld a patch to close up the section of floor where it was previous cut. Use a wire wheel to remove the paint from where I'll be welding.


For patching material I'll use the section of metal that was cut from the van wall where the side window was installed. This is Hal's version of a skin graft.


Before welding on the van I had to make up an heavy duty 220 extension cord so the welder would reach outside.




Here's the patch welded into place. Need more practice on thin metal welding but think it will hold OK. You'll notice I didn't try to bend the metal to match the floor ridge. This metal is too thick for me to do more than a simple bend with my homemade bending rig so just welded it flat. Since the underneath of the van at this point is protected by the basement it's not that big a deal. If the patch was on a part of the floor that wasn't over the basement I would have done something different.


Before starting to weld I disconnected both the positive and negative terminals on the van battery. I've read online where some people do and some don't. Didn't want to take any chances and it's not that difficult.

Prime and paint. Using Rust-Oleum white enamel paint. Doesn't match but who's to know.


Notice the gap at each end of the patch where the floor ridge dips down. Seeing that gap got me to thinking. I'll come back to that.

Cut and stain a new sheet of plywood to match the new opening. After making sure it's a good fit take the plywood into the garage and use it as guide for the new hatch frame.


Here you can see the whole floor after staining along with the new hatch frame.


Speaking of bodies, I'm staring at the new opening and wondered to myself if I would fit in the basement. It took some maneuvering but was able to get all six foot of me, head and all, into the basement. After I got my arms inside couldn't reach the camera.


The plywood will cover the edge of the side plastic step so have to secure the step first. Here are the original fasteners for the side step. I replaced them with metal bolts and nuts.


Use #10 sheet metal screws at each corner of each of the three plywood sheets that make up the top floor layer. My plan is to bolt each cabinet I add in place through the floor. I'll be doing the same to the sofa-bed. It's the bolted down furniture that will keep the plywood in place. The twelve screws should work until then, hopefully.


continued -

 

BFD (Big Flooring Deal), Post 2

With the floor down, time to cover it. I'd thought about indoor-outdoor carpet but if I'm camping in the rain, which does happen, it would surely get wet and that could be a problem. So I'm going with vinyl flooring. Next choice is either sheet vinyl or tile squares. Since I still haul things in the van there is a chance of the floor being damaged. If I go with squares and damage one it can be pried up and replaced. So tile squares it is.

The floor space measures roughly 6' x 10'. Went to Lowe' to see what they had. The vinyl tiles I picked come in boxes that cover 30 square feet so two boxes should do it. They were around $25 a box. Lowe's also sells the tiles as singles which is a plus since I'll want to buy some extras in case replacements are needed in the future. Can't count on this particular style to still be available after a year or two.

I'll be laying down the tiles in a diagonal or, as I think of it, diamond pattern. I prefer the way this pattern looks but more importantly laid this way the floor seams won't line up with the vinyl tile's seams. The adhesive backing should help hold the floor seams in place.

Start by laying out some squares without removing the backing paper to get an idea how it all looks. Have to plan ahead so that there won't be any small cut pieces against a step edge.


Find and mark the center line of the van. Do this by snapping a chalk line.


Remove the paper backing from the first tile square and lay it down. Use the J-roller you can see in the below picture to press down on the square so it will adhere. This is the same J-roller I bought to apply the Formica to the sofa-bed sides.


Keep adding tile squares building out from the first one.




The downside to the diamond pattern is you have to cut more pieces for around the edges than you would with a straight pattern but I think it's worth the extra work. It helps a small space appear a little larger, at least in my eyes.


As hard as I tried there are still very small gaps between some squares.


Done with laying the tiles.


Cut a new hatch from plywood. Chisel out a place for the pull handle then stain. Apply tiles but instead of trying to match the pattern surrounding the hatchway I made it symmetric to the hatch.


I cut the heads off two 1/4" bolts and welded them to the bottom of the hatchway frame. The original idea was to use the bolts to hold the frame in place but after a test fit I realized the frame was adding rigidity to the floor. So I added another set of bolts to the frame.


Drilled holes in the floor to line up with the four bolts


With the frame bolted into place it made a big difference in the stiffness of the rear floor. There was at least a 1/4" of flex that went away.


Re-used the hinges from the first hatch.


After bolting the frame into place used a Dremel to cut off the excess bolt end. I then took a file to the bolt end till it was smooth. I know I'll be banging my hands into the bolt ends when reaching into the basement so this should help reduce possible injuries.


Looks good.


Last thing I tackled was the side step edge. While doing this project and getting in and out of the van my toe caught the edge of one tile already glued in place along this edge and caused it to flip right up. So some kind of edging along here was obviously needed. I'm going with a simple aluminum angled edge strip I had on hand.


The problem is here where the floor curves. The aluminum edging sure won't bend to fit that shape. I have a couple ideas what to do here but none that I like so just going to punt and leave it be for the present.


Screwed the edging into place.


OK, that's it for the floor. I still have to do so kind of edging strips along the back and along the front but that can wait till later. Once I finished and was looking back over the work it amazed me just how much of difference $50 worth of tile and can make to the look and "feel" of the van.

 

BFD (Big Flooring Deal), Post 3

Meant to include this in the previous post but forgot. So I'm looking at the finished floor patch and notice the gap at each end.


Occurs to me that would be a perfect spot to run wires into the basement for a light. Wasn't on the original agenda but why not? Still had some of the rigid LED light strip left over from the fluorescent light fixture upgrade. Cut the strip in half.


Cut up some scrap plexiglas pieces and add a switch. Then use the acrylic cement to glue up a led light fixture.


I notched the insides of the small square fitting on the right end so the switch will snap into place and stay.


Wire it all up to the house battery then use 3M VHB double sided tape to attach it to the roof of the basement. Test. With the aluminum walls of the basement acting like mirrors it's very bright.


Last step. Take scary looking picture.

 

love that last picture!