Tom & Shelly's build

[bdosborn]

NCAR just inked the deal for the next gen supercomputer, this will be the 3rd one since they've opened.
Bruce

[Tom&Shelly]

NCAR just inked the deal for the next gen supercomputer, this will be the 3rd one since they've opened.
Bruce

Nice! Thank you for the information Bruce.

I've worked with meteorologists in the past on laser communications research, and my understanding is that by having weather data from boxes of a few hundred meters to a kilometer or so--from satellites, in situ weather stations, etc.--they can feed all that data into mathematical models, on the super computers, and make really accurate predictions. The equations all have to be solved simultaneously (from all over the world) hence the need for the super computers. It's actually similar to analyses of turbulence, around aircraft (or teardrops and tow vehicles), except for the latter, the grid size is on the order of millimeters.

Of course, the cloud cover modeling database for the solar energy app already exists in some form. I'll have to look into it to see if it's something I could use in my laser communications consulting business, and if it's available. I know a meteorologist who specializes in cloud cover models for lasercom, but he charges beaucoup bucks for high fidelity models. A lower fidelity, lower cost model would be appropriate for many initial engineering studies. But most of us who have looked, because of our backgrounds, have looked to the astronomy community. I don't think we thought about the solar energy folks.

Tom

[Tom&Shelly]

Based on the latest curves you show, which angle (fixed angle) yields the best return each year in power generation?

Hi Tim,

The highest total energy per year comes from the 60 degree elevation curve. But, of course, in our case (for either the teardrop, or garage), we'll most likely be using the batteries every few days or weeks, so that's probably the better time frame for us to consider.

Tom

[Tom&Shelly]

Finally have the main electrical box prototyped



The circular thing is an AiLi battery capacity meter, the other circular thing is the Battery-PD 4045 cut-off switch, the big black thing is the PD 4045, and the little black thing is the solar charge controller. The real little black thing is a single fuse holder I was going to use for the solar panel to controller circuit, but I decided not to when I realized the fuse holder requires 3/16 inch female blade disconnects. No one else seems to have a fuse there anyway.

I need to shorten the cable to the hatch. The little wire going across the galley is for the right side rear running light, and will be hidden by the top drawer/counter lighting.

On the side of the box, we have an AC outlet (GFI), USB port and cigarette lighter port.

Incidentally, when I started the build 3 years ago, they only had that type of USB port in white. Shelly really wanted a black one here, to match everything else, and Amazon now sells them. This one came with an unadvertised feature (a real one--not a bug, which is what that phrase normally means in my lexicon): The top USB fast-charges our telephones. I'd order some new white ones for inside the teardrop cabin if they advertised it, and I knew that's what I'd get.



I say "prototype", above, because I decided I should make the box about an inch and 5/8ths deeper to better hold the rats nest inside. If I push, I can get it to close, but it would be better (especially since the PD4045 has a fan and I designed it to push air out a notch behind the counter) if it were a little deeper. I have it positioned in the picture so the front of the box is flush with the oak holding the hatch strut, which is where I think I want it.

So, I'm not proud of this, but here's what it looks like inside:



Yuck! Let's see, the big terminal block on the galley wall is the 12 VDC bus; connected to the battery, except for the AiLi meter terminal. One of those black cables is for tow vehicle charging. The other two next to it are for the USB ports on the headboard, and they go to the lower terminal block, which connects (via 14 gauge speaker wire) to the terminal block right behind the PD 4045. Meanwhile the 16/6 cable coming in from the top are the other lines from the tow vehicle. They go behind the wires on the 12 VDC bus to another terminal block which connects to the hatch cable. And then the last black cable from the top is the brake wire. We don't touch that here! Then there is the AC wiring coming back from the PD 4045, and ....

What! You're confused!? Well, luckily, the electrons know where to go...



At least I used color coded heat shrink to make it look neater. The color coding helps to get the wires back in the right place if I have to remove a wire, but the main purpose is to hide bad solder joints.

Anyway, I tested the AC circuits and the PD 4045 12 volt side to the teardrop lights and power ports, and it all works.

Tom

[tony.latham]

So, I'm not proud of this, but here's what it looks like inside:

It looks organized. So nice job.

I'm happy to be a 12-volt Neanderthal.

Tony

[Tom&Shelly]

The MC 4 connectors for solar panels seem a little bulky for a teardrop, so I decided to use a panel mount XT-60. Mounted it on the plastic box behind the left fender, right next to the AC power in:



I used an XT-60 plug as a dust cap. Here it is open:



Inside, there is yet another black cable (10 gauge) that runs up to the solar controller in the galley electrical box.

Tom

[Tom&Shelly]

So, I'm not proud of this, but here's what it looks like inside:

It looks organized. So nice job.

I'm happy to be a 12-volt Neanderthal.

Tony

Thank you Tony.

I saved the hard stuff for the end, so today was frustrating, but I think I agree with the 12 volt sentiment! Seems to me the PD 4045 could be better designed, physically, for installation. But then, 120 VAC stuff is designed for houses, not moving vehicles, and modifying electrical boxes, screwing down 12 gauge stranded wire to outlets, etc. is not optimal.

Tom

[Tom&Shelly]

Next job will be adding the battery



I found this Group 27 battery on Amazon, slightly cheaper than at the local auto-parts stores. It's made in Vietnam. So much for certain talk about only buying batteries locally due to high shipping costs! On the other hand, the UPS man had to carry it 120 feet up our muddy driveway, and he still isn't speaking to us!

The battery weighs 65 lbs, which I knew when I designed the battery box, but after lifting it, I have a better than theoretical sense of what that means, and I'm hoping I did a good enough job!



There are two compartments because I originally considered two 6 volt golf cart batteries. 120 lbs on two aluminum boxes held to two pieces of angle aluminum by a few dozen horizontal 4-40 screws (shearing force). Hmm...

Well, we'll keep an eye on it.

I have no real way to clamp it down, but plan to use scrap foam to keep it from moving around. I plan to cut a piece to fit on top and will screw down the lid.

Tom

[noseoil]

Looks really good, a nice clean installation! Wiring is so much fun, the 12 volt battery, 110 volt shore power, running lights, brake lights, turn signals, converters, inverters, usb ports, reading lights, etc. etc. etc.

It's a minor PITA, but nice once it's all done, working, then you can forget about it until the battery needs to be replaced.

[lfhoward]

Your wiring hub is a great idea! If anything ever needs work, it's all right there in one place and easily accessible. Nice work.

[Tom&Shelly]

Thanks guys! I always wanted everything to terminate there, just wish I could have figured out a neater way to do it!

Installed the battery this morning



Turns out, getting a 65 lb battery in under the counter isn't too tricky, but getting it out again, to adjust the size of the foam around it, is. I was thinking I'd need to take off the counter, then the bottom of the shelf, etc. but managed to figure out a trick, that wouldn't work with an unsealed battery. If it's ever stolen, I imagine the thieves will break the counter to get it.

Seems to charge well on either the PD 4045 or the tow vehicle. It started out too charged to really take a lot of current, but it appears the ~twenty foot run from alternator to teardrop battery won't be an issue. The 3rd gen Taco appears to disconnect the charging line when the ignition is off, but there did seem to be a small parasitic draw when plugged in, so I'll investigate that further.

I'm planning on charging overnight with the PD 4045, then setting the AiLi to "full".

Still have to run a ground wire from the trailer frame, a temperature probe to the battery from the solar charge controller, and a pigtail from one of the 12 vdc circuits to an XT-30 connector in anticipation of the counter lights. Then I'll build a new box out of Baltic birch, varnish it, and change over all the components. That last step seems like it might take a whole day or so!

Tom

[tony.latham]

Turns out, getting a 65 lb battery in under the counter isn't too tricky...

So... was there a moment where you heard yourself say, "Why didn't I buy lithium?



Tony

[Tom&Shelly]

Turns out, getting a 65 lb battery in under the counter isn't too tricky...

So... was there a moment where you heard yourself say, "Why didn't I buy lithium?



Tony

Oddly enough, it was "why didn't I take home those spent nuclear fuel rods when I had the chance". Working in New Mexico has its perks.

That would also put that propane vs diesel heater debate into perspective.

Tom

[Tom&Shelly]

Well, I thought I'd finished the electrical box today



Tested all of the electrical circuits, tested charging with the tow vehicle and with the PD 4045. Then I tried to close the hatch



Somewhere along the line, I forgot where that strut goes when the hatch closes.

So...for my next trick...

I'll have to take the box out, and figure out how deep the strut would go. One idea is simply make a third box, but this one with a slant built in all the way across. I'd prefer a quicker fix on the existing box, but one that still looks good, by effectively cutting that corner out. Not sure how to do that neatly though. It'll almost certainly involve taking all the electrical stuff out, performing the rocket surgery, and then putting it back (took me several hours this morning to put it all back in this box.)

I have a feeling, somewhere along the lines I'm going to have to cut some straight lines in the already built box. Probably also involve some serious sanding and recoating with varnish <sigh>.

Good thing we have one more big snow storm coming tomorrow.

In other news, I glued a few chunks of foam to the top of the battery



Right before discovering the strut issue, I was going to test fit the battery lid/drawers. Hopefully the foam will keep it from moving around on bumpy roads.

Found the battery read 13.4 volts when fully charged. Took a few minutes with a load (galley light) to bring it to the 12.7 volts I expect to see.

The battery was fully charged, so I could only make a few preliminary measurements on the chargers: The PD 4045 charged at 13.6 volts, 0.5 amps, while the tow vehicle was at 14.0 volts at 0.6 amps. So I don't think the tow vehicle will hurt the battery--in the fully charged state, both methods of charge deliver essentially the same thing to the battery. After the snow storm I'll try draining it some and see what happens. My expectations (and calculations) at this point are that the tow vehicle will take a few hours to charge a well drained battery, but is capable of doing the job (through the ~20 feet of 10 gauge wire and 7 pin connector).

Tom

[tony.latham]

Somewhere along the line...

So... what cussword burst forth? Anything extra-coarse that I could add to my vocabulary for one of my future screw-ups?



Tony