Final Odds n Ends

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This weekend I began what will be 2 weeks of punch list work.  Meaning I finished all the little odds n ends that were too time consuming to deal with when I was building.  It also means that I was fixing things that I broke when building other things (wall dings etc).

The weekend began by renting a 12ft ladder from Home Depot.  I could have bought one, but they are $280 and I just don’t see the need when a rental was 22 bucks.

Fan Fix

When I originally installed the fan, very little air was blowing.  I speculated that it needed some room away from the ceiling to let aerodynamics work properly.

I pulled down the ceiling fan and installed a 24 inch rod on it.  I also decided to install a special switch that would reverse the direction of the fan.  That is a very useful feature in the winter heating season where you want the fan sucking instead of blowing.  Here is the circuit diagram in case you want to add one to your DC fan (I did not draw this, just stole it from a google search).

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With everything back together I tested the fan and guess what?  It actually blows and sucks air!  Lesson: make sure you have enough space around your fan….tough in a tiny house, but important.

Stove Trim

The other task I needed the ladder for was the trim around the stove pipe.  This was a very complex piece since the pipe goes thru both the flat and sloped ceiling.  I had my friend Tim make me templates on his CAD system so I could trace them onto cardboard and then metal.

The trim is made in two pieces and are different sizes.  I made cardboard ones first, then when I thought I had it right the cardboard helped me mark the sheet of aluminum.  I use thin gauge aluminum and scribe it with a sharp utility knife.  If you scribe it deep enough, the pieces can be wiggled a bit and will break at the scribed line.  The process was a real pain in the ass let me tell you! If possible install your chimney so standard trim can be used.

Kitchen Trim

I wanted something to break up the walls of the kitchen and make the control panels not look so much like well….control panels.  I decided to use up the leftover paneling from the porch project.

Using a liberal amount of Liquid Nails paneling formula and a few strategically placed finish nails I added about 24 inches of paneling.  I will add some nice black coat hooks and who knows what else.  Might find an old school telephone for the wall as well.

Water Tank

The last thing needed before the plumber comes is the water tank.  I built up the “tee” pipe with all the doo-dads you need.  It starts with a gate valve which lets me block the pipe so I can force water to the other house.  Then a check valve is installed so that the tank can’t push water back into the well.  Next a connection to the tank, pressure gauge, relief valve, and pressure switch is made.  The pressure switch “switches” at 60 PSI which will command my pump controller to shut off.  The relief valve opens if that fails to happen.

After installation I discovered that there was a leak which sucks since this stuff is really packed in there.  The cause was the plastic fitting on the tank.  The instructions to hand tighten and then some are totally bogus.

My solution was to rip out the tank and use a pipe sealant rather than teflon tape.  Then I tightened it pretty darn tight.  After pressurizing it for the second time….there was still a leak!

For the third attempt, I decided to leave everything in the hole and tighten it in place.  Using a mother adjustable wrench I tightened it to the point where I thought it was ready to crack.  After pressurizing the third time, it was still leaking a tiny bit.  I’m going to let it be and see if the pipe sealant stops it up.  There is nothing in the hole that can be damaged, so a little drip is not an issue.  During humid months the tank will sweat which can produce a lot of moisture….so a little drip is acceptable (to me anyway).

Whats Next?

This Thurs the plumber is coming for final plumbing work.  The propane company will be coming by next Thurs to install a 200 pound tank.  This weekend, I will be doing more punch list items, cleanup, and hardwood floor shopping.  If all goes well, I should be installing the flooring by the third week in Sept.  A move in date of Oct 1 looks to be doable.  Stay Tuned!

Converting AC LED Lights to DC

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They are doing some pretty cool stuff with recessed LED lights these days.  Unfortunately, this style of LED light requires 120V AC not 12V DC.  Some of the smaller track lighting does run from 12V DC directly.

Internally these lights do run from DC, there is just a converter circuit inside that makes the 120V AC into a DC voltage.  Some lights have this circuit built internal to the light and it’s not easy to get at.  Others have this circuit in a box that is very easy to get at.

A couple of weeks ago, I found some LED lights on clearance at Home Depot for about 10 bucks each.  I opened the package and saw that the AC to DC converter was in a small plastic box bolted to the back of the light.  I immediately, bought up 7 lights for use in my Bodega.

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Constant Current LED Driver
LED’s operate on just enough voltage to make them draw their rated amperage.  For some LED’s this will be 8.5 volts, others might be only 6.  You need a special circuit to drive them called a constant current LED driver.

In my case the LED’s I bought require .6 amps.  I needed a constant current driver that would accept 12V DC and drive an LED at .6 amps.  I found the LDD-700H at Jameco for $6.95 in single unit quantities (data sheet here).  It will supply .7 amps to the LED which is a bit more than the driver I removed, but still within the tolerance for the LED’s.  There are other versions of the LDD that can supply less current if that’s what your LED requires.

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THe LDD-700 has 9 small pins on it for electrical connections.  Don’t let the small pins scare you, it’s really easy to connect to.  The outside two pins on each corner are connected together so you actually end up with a pretty big target to apply solder.  One corner has 3 pins.  This third pin is for a dimming function that you will not use.  The spec sheet says to leave this pin open.  I suggest you cut this pin off flush with the case and put some electrical tape over it.

Making Connections
My lights come with an adapter that screws into the light socket with an orange plug.  The light has an orange plug and a white box.  I cut the wired from the box and removed it.  The remaining wires get soldered to the LDD.

The LED wires (white and grey) are connected to the Vout terminals [white to (-) and black to  (+)].  Colors may vary so do your research.

The input wires go to the orange plug.  I decided to install a 2 amp blade style automotive fuse on one line “just in case”.  One side of the fuse is soldered to the pins and the side to the orange plug wire.

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When all the wires are connected I applied some electrical tape to keep things secure.  Over the electrical tape I used some large heat shrink tubing.

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Its Alive!
I screwed the adapter into my recessed light fixture and attached the orange plug making sure the on/off switch was “off”.  I connected my amp meter across the switch to measure the current draw of the light.

My first measurement read 1.6 amps, the light did not go on, and the LDD got really hot.  It turns out that I’m a dumbass and swapped the plus and minus wires.  In the realms outside of house wiring, a black wire is generally the minus side of a DC circuit, in-house wiring its positive.  subconsciously I connected it without thinking because my brain is wired that way.  If someone with 20+ years of experience can screw up, you can too…..always double check your work (and buy a spare LDD just in case) :).

After replacing the LDD, the fixture lit up and drew .659 amps.  Multiplying my battery voltage of 12.22 volts with .659 amps we get 8.05 watts of power being consumed by each fixture.  The light output is excellent and just right for the size of my kitchen.

Now that I have lights, I can work late into the night without having to operate the generator.  Very happy with the results of this project.

Electrical Complete!

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Busy weekend at the Bodega.  saturday I put most of the finishing touches on the electrical system.  Sunday I spent the day running errands like a much-needed oil change for the Spark.  In the afternoon I met up with the Tumbweed guys at the workshop and gave my presentation to about 30 (hopefully) future tiny home dwellers.

Executive Decision

I have made the decision to use sheetrock rather than tongue and groove pine for the wall coverings.  I was not sure about the look of so much pine on the cathedral ceiling.  I think its going to look like an upside down boat when sitting in the living room.  I will sheetrock the place and then apply a T&G pine as an accent in the kitchen and maybe carry it around to the front wall.

If this were a trailer based tiny house, the decision would have been different.  For something fixed drywall will hold up very nicely and is durable enough.  I also will have the luxury of changing paint colors if I want to do something a bit different.  I have started watching YouTube videos on drywall installation and taping to prepare myself for what I am sure will be a dusty month of hell putting my wall covering on.

Final Electrical

With my battery enclosure installed, I needed to run wires to the disconnect.  I bought some 2 gauge welding cable from eBay to complete these runs.  I bought a bit extra so I could rip out the very stiff 2 gauge wire in the breaker panel as well.

Welding cable is an excellent type of wire for DC applications.  It’s very flexible, the insulation is very abrasion resistant, it handles temperatures up to 105C. Due to its high temperature rating, the NEC will allow it to carry 130 amps, but it will actually carry 200 according to manufacturer data.

The only downside to welding cable is fishing it thru conduit.  The rubberized jacket grips the conduit and is a real bitch to pull.  I attempted to fish thru a 20ft bundle and got stuck about 4ft from the end.  Fortunately, I was not stuck that bad and was able to pull the bundle out.  A $8.00 bottle of pulling lube from home depot liberally applied to the cable cured this issue and I was able to get my wires thru.  Reminded me of cow insemination as I slathered the bottle of goo all over my cable.

The disconnect that I bought came equipped with fuse holders that were not for type R fuses.  I could not locate the type R parts from Square D, so I just ordered a 3 pole fuse holder from McMaster Carr and removed the fuse blocks.  The terminals from one end of the fuse block replaced the fuse holder on the switch side of the disconnect without any problem.  They make these disconnects with a number of options, one of which is no fuse holder…the configuration I have it in now.

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I have a total of 5 wires into the disconnect.  Two are for my 60 amp 12V DC circuits (+ side) that run the house.  One is a 60 amp circuit that will deliver power from my panels in the future.  There is a black wire used as the minus side of the 12V DC circuit.  Last, there is a large green wire for earth ground.

The three red wires are switched thru the disconnect, and the black wire is via a shunt to the panel.  The shunt allows me to measure the amount of current going into and out of the battery.  The ground wire connects to my ground rod.

My secondary panel holds the charge controller and pump controller (not installed).  I’m sure a bunch of other doo-dads will make their way into this panel…which is why I bought one that is a bit larger because you never know.

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“There are four lights”

I ripped out the ceiling boxes I originally installed and replaced them with 4 inch recessed lighting boxes.  I managed to find some LED lights on clearance that I can modify to meet make some kick ass lights for my kitchen and bath.  These lights have a nice nickel finish and fit in 4 inch housings.

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They are intended to replace 120V lamps and have a small plastic power supply box mounted on them.  The box says 120V AC in, 12VDC out at .6 amps.  I will be ripping that out and replacing it with a LDD-700 constant current LED driver which costs about 6 bucks.  It will require some soldering skills, but in the end I will have a nice set of 4 really bright lights in the kitchen and bath that run from 12V DC.  I powered one up just to see it in action and it looks sweet (I was over-driving it by a ton, so it might end up a bit dimmer in the end).

Generator Connection

The last bit of electrical work I wanted to complete was a 120V generator curcuit that can be used to power the AC unit and whatever else I need.  I installed a plug and disconnect to the generator box and ran a conduit thru the wall to a dedicated 120V outlet.  I then ran another outlet to the laundry room in case I want to power a washing machine in there.  I’m not sure how my little “bonus” circuit fits into the NEC.  I don’t see any reason why it would be an issue.  I have two disconnecting means within sight of the generator and it’s not connected to the houses electrical system….its just a fancy extension cord.

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Tumbleweed Workshop

Sunday I spent a couple hours talking to the folks attending the Tumbleweed workshop in Boston.  I gave about an hour long presentation and showed off the Bodega and my XS house.  The atendees had lots of great questions.  Attending these workshops helps me to get a better sense of how I should present my info here on the blog.   It was also pretty cool to meet Deek from Relax Shacks in person.

Inspections

This Saturday morning I have my final framing inspection and the electrical inspection.  The building inspector has already seen everything so I don’t think he will have any issues.  The electrical inspector I have no idea what he will care about….hopefully nothing.

Weekend Work

This weekend I will be prepping for wall covering installation and installing pink insulation.  I’m not sure how much insulation I can install but I hope its all or most of it.  I would really like to start hanging drywall.

Electrical, Trim, and Siding

This week I will update my progress on the electrical and trim work on the Bodega

Electrical

The outlets and switches in the Bodega are wired like any others with a few exceptions.  First I am using 10AWG romex with the black conductor being the positive (+) side of 12V and the white being the minus (-) side.  The uninsulated ground conductor is wired to all the green screws on each receptacle and switch.  Switches and receptacles are a bit different. I am using a 6-20P style receptacle and switches rated for DC loads.

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The load center is where things get a bit interesting.  I am using a six slot QO series load center which is available at Home Depot.  The breakers are also QO series which are DC rated to 48V.  Load centers have 4 input connections: L1, L2, Neutral, and Ground.  L1 and L2 in a DC setup are connected to the (+) side of the battery.  I am running these two legs thru a fused DC disconnect.  The neutral (-) connection will be run thru a 500 amp shunt that my system monitor will use to measure the current into and out of the battery bank.  The ground is connected to the neutral bar with a short length of wire and then to the ground rod.

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Back Door Switches Installed

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Main Disconnect

I have added a second panel below the load center that will house a charge controller and pump controller and whatever misc electrical crap that I may need to install.

Trim

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Made drying racks by screwing scrap boards to the wall studs

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I measured and cut plywood that will be used to cover the soffit areas.  I used 3/8 thick sanded plywood for this.  Each piece was given a coat of primer before installation so the trim paint will stick well.  I have decided to keep my soffits flush to the roof rafters rather than meeting the wall at 90 degrees.  There is a very tight corner to be dealt with in this configuration.  I installed some 1×4 trim in this corner to give it a finished look.  This joint is caulked and smoothed to give a nice finished appearance.

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Plywood soffit without trim board

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Trim board installed and caulked

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The corners have been fitted with 1×4 trim as well.  I was going to use 1×6 but decided that it would be too wide and look dumb.

Siding

I originally wanted to install cedar siding, but my concerns about it weathering properly made me change my mind.  Nearby homes with natural siding are not weathering well at all.  Being in the middle of the woods there are lots of mold spores that create black or green growth. I just didn’t want to deal with power washing the place every spring.

Anderson over at Tall Man Tiny Mansion turned me on to siding by LP called LP Smartside.  It’s an OSB product that comes with fake wood grain on one side and a coat of primer.  Its super rugged unlike the cement based siding products.  I do have concerns about water absorption and rotting but the product comes with a 50 year warranty.  If I manage the water runoff around the house and use a quality paint I think I can make it last.  I expect to paint the place every 5 years or so.  With only 800 square feet of area this should be a weekend project.

I ordered 136 pieces of 6″ x 16′ siding which will be delivered this coming weekend.  I will be setting up an assembly line to paint it prior to installation.  Here is the mockup of what a corner of the Bodega will look like.

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Paint is not 100% uniform since I used a rag to put it on

Electrical Part 2

In this post I will discuss the layout of the receptacles and lights.

Correction

In my last post the schematic lists a Square D H361RB disconnect.  I have switched to a H362RB which is a 60 amp unit and will offer more flexibility in the future should I decide to add a small inverter for the washing machine.

Receptacles

I have selected a dual receptacle that is typically used for 250V circuits.  It is a NEMA 6-20P style receptacle.  The ones I purchased are made by Morris and are part number 82205.

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The one feature I really like on these units is the wire attachment method.  Most receptacles and switches you make a wire loop and attach it to the screw terminal.  Another common method, you strip the end of the wire and stick it in a hole that contains a spring loaded clamp.  I hate the spring loaded clamps because I think they wear out over time and get loose.  Screw terminals work but you need to make the loop, screw it down, and make it look good.

These Morris receptacles have the hole in the back where you tighten down the screw to clamp the wire in place.  Its the best of both attachment methods in my opinion.  Since I will be working with 10 gauge romex in this application the easier you can make it the better.

Switches

First of all, you can’t use normal switches in my application.  Wall switches are rated for AC only and will quickly burn out when switching larger DC loads.  For small loads they may work just fine for a while depending on the quality of the switch.

I have selected a switch made by Leviton part number 12021-2l.  This is a DC rated (up to 24V) switch that can switch 3 amps.  This is more than enough current for lights and other small DC appliances.

Technically, these switches are not rated for the the amount of power that each of my branch circuits can produce which is 20 amps.  It seems that NEC 404.14 only requires that the switches must be rated for the loads they are used to switch.  Since I will be using them to switch lights that are about 1/2 amp, I’m sure they will work just fine in my application.

Receptacle spacing

When installing receptacles there is a rule in the NEC that makes you put outlets within 6ft of an appliance.  If you had a lamp with a 6ft cord there should be no place in the room where that cord would not reach a receptacle.

Required Circuits

The NEC requires certain circuits in a dwelling unit.  THe kitchen needs to have 2 that supply only the receptacles, lights must be on a different circuit.  The laundry room and bathroom should have a circuit each.  The laundry circuit should not run anything except the stuff in the laundry room.  My bathroom circuit runs the lights and receptacles in the bath.  The laundry circuit runs the hot water heater and washing machine which are located in the same cubby.

Wiring

Since I am using 12VDC to run everything, the voltage loss in the wiring is a concern.  I will be using 10 gauge wire for everything to keep the voltage loss to less than .6V @15 amps on the longest run.  I will never run 15 amps on any of these circuits so this is really a worst case number.

Misc

There is a charge controller and other instrumentation that I will be installing. The charge controller positive lead is looped thru the main disconnect so that the batteries will stop charging when the disconnect is opened.  The well control box will be connected to one of my circuits and the other side run down to the pump.  I will mount the charge controller and well controller in a load center box that has had the innards removed.  Turns out load center boxes are cheap compared to NEMA 1 boxes and they have a nice little door on the front where I can hide any lights or switches I might decide to add.

Weekend

This weekend I plan to engage in a ton of wiring work and finish up some minor framing details in the cabinets and closets.  I also need to de-clutter the place as its gotten full of tools and other stuff that is not needed going forward.

Electrical Plans: Part 1

Today I will share the electrical design for the Bodega.  As you might have read in the past, it will be 100 percent off grid and most everything will run from 12vDC.  I will probably do a series of posts on the design since there is a lot to go over.  I will start by saying that I take no responsibility if you copy my design and burn your house down (or electrocute yourself).  The following 2 pics are the schematic diagram and the layout for electrical boxes:

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Circuit Description

Life begins in the battery box where a pair of very large batteries (300AH+) will deliver 12V to a disconnect.  The batteries will be housed in some kind of box that will be vented to the outside so that hydrogen gas does not build up.  I will either put the batteries in the loft in plastic battery boxes or in a job box outside the house.  If its outside the house I will omit the hydrogen vent as job boxes are pretty well ventilated.

The disconnect will be a 3 pole unit rated at 60 amps that can switch 600VDC.  Beware not all disconnects are DC rated.  You will find that the DC rated ones are quite expensive ($250-$350).  The unit I have selected contains fuse holders more about that in a bit.  The three poles of the disconnect will switch two wires connected to the positive side of the battery and the charge circuit (charge controller).  When the disconnect is OFF everything will really be off.

The ground rod will be connected to the negative of the battery inside the disconnect.  The metal parts of all electrical devices will connect here along with the negative terminal of all lights receptacles etc.  I reserve the right to move this connection to inside the load center if I discover something in the code that requires it (I’m thinking it might…more research to do).

The load center is a Square D QO series that contains 6 breakers.  No main breaker is required on panels with 6 or less breakers.  The circuit breakers will be 20 amp QO series which are DC rated to 48 volts.  On gotcha is that their DC interrupting rating (AIC) is only 5000 amps.  Code requires that you place a fuse in series that provides a larger interrupting capacity (cant remember what value right now).  The disconnect I picked has slots for class R fuses which provides the required level of protection.

The last interesting bit is the charge controller which is shown for reference only since I have not picked an actual unit yet.  They all have about the same wiring configuration so whats shown is correct.

Next post

I will write more on the electrical design…

PV Panel Surge Supression & Updates

As you may have read in the news we got hit with some pretty nasty weather here in the Northeast this weekend.  I watched a wall of water head my way as I worked on things Saturday morning.

I ordered a surge suppressor from Midnight Solar a few weeks back and has yet to install it.  I opened the panel for my electrical system and connected the red and black wires to a pair of unused terminals.  I then connected the green wire to my ground stake.  As expected the blue lights inside the device lit up to tell me it was working.

The storm passed without incident however I soon discovered that the surge suppressor is very power hungry!  My Xantrex system monitor went from -0.1 amp to -0.4 amps.  The fan on my composting toilet draws about .1 amp under normal conditions.  The additional .2-.3 amps was going to feed the lights and leakage currents thru the surge suppressor.

Needless to say its unacceptable to waste this much power so I disconnected the device and will reconnect it when there is a change of lightning.  I’m thinking that there may be a way to install a diode module between the charge controller and panel that will prevent using power from the batteries.  I don’t mind wasting a bit of PV power but a constant draw on the batteries is something I can’t live with.

Another option may be to tame the power consumption by removing the blue lights.

 

Plumber Update

As expected the plumber called me yesterday afternoon to say he would not be coming.  The next work day will be Thursday.  I wanted to pour concrete this weekend…I guess that’s not going to happen.  Thing that pisses me off is that I could install these drain pipes in 2 hours.