Now the fun starts

[MickinOz]

It has been slow going. I find myself doing anything but working on the trailer.
Friday we went to Adelaide for medical reasons.
But I squeezed in a side trip to Gaganis Bros for pizza making supplies, a look in Austral Meats' new retail store at their dry aged beef, and bought a few bits for the trailer from Bunnings.
I was torn between gas struts and another set of folding struts like I made for Ol' #1.
Then I saw some nice powder coated hinges and draw latches and my mind was made up.

Made a nice pizza tonight - Gaganis Bros had fresh yeast. Had to try that, I've never been able to get anything but instant dry yeast.
Damn it improved the flavour of the dough in my opinion.

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Austral Meats had whole t-bones 60 days dry aged. Only $70 per kilo.
My calculator informs me this is a $1000 rack of t-bones.

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Made these struts this arvo. They took about a tenth of the time the last lot took. Knew what I wanted to do this time, I guess.

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[MickinOz]

Got the struts installed. It's a good thing top and bottom hinges are identical. The way I have installed them, the bloody draw latches tend to re-hook themselves while I'm closing the hatch. Doesn't do 'em any good, to put it mildly. I was able to reassemble the one that flew apart.
So today, I will need to spend 5 minutes with a screw driver and turn them over so the latch hangs down when disengaged.

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Before installing all the screws, I put my phone on delay and closed the hatch to check the geometry was all good.
You need the closed strut pointing into clear space, and make sure there is enough clearance between mounts that the strut can close without any binding.
Happy to report I got it right first time.

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[JasenC]

Nice.

I'm still debating on gas struts or fabricate something like you have, I'm leaning towards the latter.

[MickinOz]

I'd like to use gas, but I stress about the stress on the hinge.
The struts I make aren't much cheaper than the cost of gas struts at Bunnings. But Bunnings is 125 miles away.....

[MickinOz]

Progress report.
Filled all screw holes, sanded and coated the entire exterior in marine grade exterior polyurethane varnish..
Had a change of mind and painted the visible bits of the chassis in black epoxy. Sure shoulda done that before I built a cabin on it.
Put new wheel bearings and seals in.
Since my son's business trailers have been coming in for urgent maintenance, I've gotten quicker at it. I can now do two hubs and reinstall in 1 1/2 hours with one beer break between wheels. I may come up with a manual press for pulling in the new races, that'll speed it up more. The main trick I found is leaving the wheel bolted to the hub and just slide the whole lot off after removing the pin and castellated nut.
Then I can just set the whole lot on top of the wheelie bun and knock the old races and the old grease straight into the bin, and there is no struggle at all holding onto the hub, the wheel holds it all very nicely thanks.
Decided battery will be strapped to the floor. I'm going against my own advice and not putting this little battery in a box. But I will be putting insulation over the terminals.

[MickinOz]

It was hard to find lugs here in town for the battery cables that would also fit my isolating switch.
The issue was around finding lugs that had a big enough hole to bolt on the switch, and were still small enough to crimp to 4mm2 cable.
So I made my own from flattened 1/2 inch copper pipe.
Also here in town, fuse blocks like I used on my first build are mongrel expensive.

So, half a day was spent fabricating with parts from the electronics junk box(es) in my shed.
I now have a mounted battery, a loom with inline fuse and isolator, and a fuse block installed.
Tomorrow just have to terminate and connect the wires from the cabin.


The pad the battery sits on is big enough for a standard 105AH FLA battery.

I made an 8 fuse block into a 4 fuse block with 4 negative connections as well.
I took a copper busbar link as used in AC house systems and cut pieces to replace the fuses on the negative side.
Pretty close approximation to the blade fuse spacing, I soldered all four links together inside the fuse block.
All solder used was 50/50. Should be strong enough.
Hard to describe, hope the pictures tell the story.

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Bus Bar.JPG (23.97 KiB) Viewed 628 times

After much head scratching about how to run the wiring as concealed as possible, I settled for clipping it inside the framing for the galley wall. The framing is two pieces of 19mm plywood laminated together then glued and screwed to the wall. I was going to be nailing the clips in into the edge grain, for want of a better term. A small potential for splitting the veneers apart.
So, call me overly cautious, but I drilled pilot holes.

Had dreams of hiding the fuse block in the cabinets inside, but
a) I would have had to work on my knees in cramped surroundings,
b) Seemed a lot of potential for it to be damaged by loose gear being thrown in the cabinet.
So it's out on the galley bulkhead in the top left corner.

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[MickinOz]

Battery and isolator installation. In an effort to get everything neat, I made the loom on the bench, including isolator mounted on plywood, one end soldered to the fuse block, inline fuse and battery lugs at the other end.
With distances between pieces at approximately the right lengths, I was able to install the fuse block, run the loom around the framing, clip it in position and install the switch so that there was no loose cable.

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The block holding the isolator is, rarely for me, not glued. Only screwed, it has to be removable for replacing the switch or changing the wire out.

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I plumbed in an Anderson plug for charging, or tapping off power in the galley.
In keeping with my desire to keep it as simple and robust as humanly possible, there will be no fixed solar panel on the roof, nor penetrations to outside for the wiring.
My working thesis is that this trailer is supposed to appeal to people who are tired of sleeping on the ground, but not yet ready to go the whole hog on a full size RV and appropriate tow vehicle.
I figure people who are moving up from tents or swags probably already have a portable folding solar panel set in the 100-200W range.

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So there it is, as simple and robust as I can make it, up to the distribution block. Tomorrow will connect the wires for the cabin lighting and power outlets, and maybe install some galley lighting.

[JasenC]

Love the soldered connections, I went that route years ago.

[MickinOz]

Thanks. I avoid it like the plague on my boats. Guaranteed galvanic corrosion, but I figure this thing should never be launched in the ocean.
Was a challenge getting the 50.50 solder to flow well with my 60W electric soldering iron. It's new, but it doesn't work as well as my ancient 40w "welder" used to.
I think I'm going to pull the heating element out of the old one and measure it, see if I can get a new part.

A day off today. I'm doing my washing, the dishes, tidying the work area, then I'm off down the RSL (the Legion?) to help a mate celebrate his retirement.

[rjgimp]

...then I'm off down the RSL (the Legion?) to help a mate celebrate his retirement.

Yep. Here in the States there are two veterans' organizations, Veterans of Foreign Wars and the American Legion. Often if they have a food and liquor license they are open to the public and they are a nice, low-key neighborhood bar. Most have a private room to rent for a party. So, heading down to the Legion (or the VFW) for a celebration is fairly common.

[MickinOz]

The galley lighting is bright.
Sure get a lot of light out of 360 mA when ya do it right.

[MickinOz]

As I go along, I try to practice KISS principles.
Keep It Simple Stupid.
But I do worry about things being a little too rudimentary.
Hopefully my galley hatch lighting installation falls under the heading of "Simple", not "Too Rudimentary".

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Hatch Wiring.JPG (67.79 KiB) Viewed 469 times

These LED's came from my son. He gave me several strings of them. You just cut off as many individual modules as you want.
He said they were 1W each, but the two I have used here draw 4.6W.
I messed around making little wedge shaped mounts to angle them toward the sides and also forward a little toward the bench. I think the forward angle wasn't necessary.
But dang they throw some light.

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I've been doing a little research. The amount of light coming from an LED is governed by the current, not the voltage. The voltage only has to be a small amount above the LED's forward voltage, then after that it's the current that counts, and the current is only voltage dependent in a very narrow window.
So I have two modules mounted in parallel drawing ~360 mA.
Presumably, therefore, one module draws around 180mA.
The small amount of research I have done suggests that the current flow is not directly proportional to the voltage.
i.e. you don't get double the current when you double the voltage.
If that is true, then you don't halve the current by halving the voltage.
So, I will experiment one night. I reckon I will put a couple of these in series and see what happens.
Maybe I can cut the current in half and still get plenty of light.

Edit: I think I'm talking out my hat. I suspect, these being modules rather than just LED's they'll have circuitry in them, at the very least current limiting resistors, so probably won't work.

[JasenC]

Add some resistors if you want to tame them down a bit also a defuser, opaque cover, helps to reduce the harshness.

[MickinOz]

I had a bit of a play last night. Putting two of these things in series reduced the current to about 45 mA!
That produced a very noticeable decline in light output.

I wasn't looking to tame the light output down too much.

Really I was just looking to drop the current back a bit, more toward what I was expecting.
(My son said he thought they were 1W, which would have been about 80mA per module.)
Being the owner of enormous bundles of brand new resistors and other bits, (there's a story for another day, give me a shout if you are in need of a few hundred schottky diodes) I suppose I could play around with leaving the modules in parallel, and just insert a resistor.

I'm a tad rusty, I left high school 45 years ago, but lessee:

V=IR

so

V/I=R

I have V=13, and I=0.360 in my circuit.

Therefore:
R = V/I = 13/0.36=36 ohms is the theoretical resistance of the modules when the lights are on.

Now, I want to limit the current to, say, 250mA
So I need a total resistance of R = V/I = 13/.25 = 52 ohms.

I've already got 36 ohms in the modules, so my current limiting series resistor needs to be 52-36 = 16 ohms

Now, if I have 16 ohms and 250mA then I have a voltage drop across the resistor of:

V=IR=0.25 x 16 = 4 volts

P = VI = 4 x 0.25 = 1 watt power handling capacity for the resistor.

So right now, I'm thinking I have an LED module that flows 360mA at 13V, and if I wish to reduce the current to 250mA, then I need a series resistor of 16 ohms and minimum 1 watt.

Also, the voltage across the LED module is now 13-4 = 9
Using the previously calculated 36 ohms, back calculating gives me V/R=I=9/36=0.25Amps
It all adds up as it should, I think.

I can't think in watts, apparently.
In LED's it's current that determines light output, so they say.
So current reduced from 360 to 250mA = 30% reduction.

If it is watts, then I have 9x0.25 = 2.25W going through the module.
That's a reduction of more than 50%. Too much, and simpler to just use one module rather than two in parallel with a resistor.

It will be interesting to see which way it works
To me, the logic is sound, it remains only to download an app for the phone to measure lumens (there must be losses - there are always losses), and give it a try.

Anyone wanna check my logic?

[MickinOz]

The family were unanimous. #2 must have a TV/DVD, like Ol' #1.
I was going to resist, but then a secondhand 12V 19 inch TV/DVD combo came up on the local FB Marketplace for $50 with remote and power pack.
I suspected it was too old to get the latest HD codecs, and I was right, but new 19 inch "Caravan" TV's are in the $300-400 range.
(Codecs changed here in about 2015 or so.)
Still leaves plenty of standard definition channels, plenty of digital radio, and of course DVD and HDM/USB inputs.
Can still watch the footy and the cricket, even the horse racing.
I tried her out and she pulls 2 amps with the DVD running, just like the newer unit in Ol' #1.
The trick though, is a decent antenna.
We are every close to the big regional transmission tower known as The Bluff.
This has proved tricky in the past, there is such a thing as too close I think, with reflected signals canceling each other, dead spots in valleys, etc.
Commercial antennas have a few problems:
Cost
Size
Form factor
Installation requirements, etc.
They seem built for looks as much as performance.

Enter the 2 bay bowtie.
I knocked this up in an hour and half, from plywood and welding filler rod.
I would have preferred to use copper wire, but the thicker the wire the wider the band width, and I didn't have any "fat" copper.
It works like a charm. Like, really well. As long as its vertical, it seems to get enough signal even if it is pointed nearly 90 degrees offline.
It's currently performing faultlessly under my carport with a steel shed between it and the transmitter.
It's flat, and of the correct size to fit inside the cabin cabinet and screw to the rear wall.
I do believe I will build another for Ol' #1.

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