The Tiny Tillson Teardrop Trailer (T4)

[BLTillson]

One more thing:

I have been getting closer on solidifying the electrical system. Since 12v vehicle electrical started off as a mystery for me my confidence level is growing but not solid. Here is my latest schematic with more details of the wire gauges. I have changed from two 6v batteries to 12v. This is mostly due to cost. This was I can buy one 12v 50AH battery now and one later and connect them in parallel. Also, If I find that one 12v battery very inadequate, I can later change it out for two 6V batteries and not buy a second 12v. I think that made sense. Anyway, Here is my current schematic. I am open to and suggestions, corrections and opinions.

Current schematic 12-26-22

Trailer Electrical 12-22.jpg (115.02 KiB) Viewed 1546 times

[BLTillson]

Okay, even more...

This is the electrical cabinet I am designing. This is the Solar controller, fuse box, Charge selector switch and the Drok battery meter. This is located in the interior cabinet at our feet, (front of the trailer).

Electrical Cabinet Layout.png (254.7 KiB) Viewed 1535 times

[pchast]

My comment would be to separate your cabin lighting into
at least 2 separate fused runs. The idea is that, in the unlikely
event that you lose one fuse, you would still have lights to see.

Otherwise that is a nice schematic design. I would use #10 wire
for all battery charging, positive buss and ground buss to battery.

[MickinOz]

Mate, reading your wiring diagram and some previous posts, I'm thinking you could be about to waste about 50% of your solar panel charging capacity.

Bear with me, I'm going to make some assumptions. Also, solar experts might chime in with more detail, and possibly see errors in my explanation.
However, my aim is to simplify as much as possible:

It appears that you will put the two 50W panels in series.
Not sure which panels you have but the Renogy Australia website lists 50W flexible solar panels at 18.5 volts 2.71 amps. Amendment: the downloadable spec sheet says maximum power is at 20.3V 2.47 amps Assuming you have the same panels, that is what will go into your batteries - 2.47 amps. So, with the panels in series, and a PWM controller, the absolute max charging current you will ever see is 2.47 amps.

The controller, being pulse width modulated, will simply turn that 2.47 amps on and off to control the battery state of charge.

As well, the open circuit voltage of the panels is listed at 24.3 volts. Two in series = 48.6V.
So, with the panels in series, you are looking to inject almost maximum input voltage to the PWM (Wanderer 10 amp controller is maximum 50V input).
If you put those two solar panels in parallel, rather than series, you will have the potential to generate 4.9 amps at 20.3 volts.
This is a much better scenario, more efficient, double the capacity, excellent match with your 10 amp PWM controller.
On a day when the sun is unobstructed and the panels are facing it properly, you will potentially get your full 100 watts from your panels, etc.

[MickinOz]

That was part one. There is a possible part two:
Solar panels that are partially obstructed, not facing the right way, etc, don't generate full voltage and current. In that case, it may indeed be preferable to put the panels in series to ensure adequate potential difference (voltage) is generate to "push" the charge into your battery.
In that case though, you will still only get maximum of 2.47 amps (and probably much less) through the PWM controller.
If the above scenario is your reason for putting the panels in series, and it could be a valid reason in some circumstances, then a maximum power point tracking controller could be a better choice than a PWM.

However, I'd just put the panels in parallel and see how it goes. With the single panel Max power voltage being 20.3 , you probably won't need to be boosting the voltage.

Remember
In series, the voltages are added together.
In parallel the amps are added together.

[BLTillson]

Thank you for the responses. That is a lot to digest from MickinOz. As I am still learning all of this aspect of teardrop construction, it will take me a bit to understand the advice. I also have some people I can ask here at home. In the meantime. Here are the actual specs of what I am using.

Renogy RNG-50DB-H Solar Panel.jpg (124.58 KiB) Viewed 1473 times

Wanderer LCD PPM.png (90.41 KiB) Viewed 1473 times

Happy New year!!

[MickinOz]

Yep, I definitely/strongly recommend you wire your solar panels in parallel, not series.

[BLTillson]

First off, in agreement with MickinOz:

Yep, I definitely/strongly recommend you wire your solar panels in parallel, not series.

I will be wiring my solar panels in parallel. I will repost the final schematic when I have tweaked it a bit more for accuracy. I am still working out the wire gauges and fuse sizes. I will post the final soon along with the resources I used to get me to the right answers.

[BLTillson]

In other news, I have been working hard at getting the floor and fender assemblies completed. This has taken me way longer than I would have expected and offered me several unique construction challenges. The biggest of those is that I have never designed and built anything like this in my life. My top priority has been to make sure that it will withstand the hardness of the road and weather. We are moving back to Oregon soon and there will be rain and more rain, (and some snow!).

I finished the floor with a Flex Seal as an undercoat to linoleum. With this I think I have ruled out any moisture reached the wood on the inside.

Flex Coated Floor.jpg (132.13 KiB) Viewed 1381 times

Lenolium Glue.jpg (149.02 KiB) Viewed 1381 times

Lenolium Installed.jpg (104.7 KiB) Viewed 1381 times

I will then trim this off the outside edge by 1" to accomodate attaching the walls to the floor and being able to glue wood to wood on the edge. More on that later.

[BLTillson]

Now the fenders. You know how when you design something and say, "Oh yeah, this will work great and be easy to build" and you are wrong! Well, the fenders have been one of those things. Great on paper, difficult under the saw and hammer. Ultimately, they will work but I have come close to scrapping the design and rethinking it. I think it is only because I have already invested so much time into them that I can't stop now. It's become a self inflicted challenge.

After getting them trimmed to close enough I flex coated the road-side and edges and began fitting the aluminum.

Fender Aluminum Fitting.jpg (98.32 KiB) Viewed 1380 times

Next, I drilled all the screw holes and using a combination of construction adhesive, a bunch of screws and clamps, I married the two for life.

Fender Aluminum Attached.jpg (148.06 KiB) Viewed 1380 times

That's one. Today I do the same to the other one. Then I will finally be able to attach then to the trailer. Oh happy day!

[BLTillson]

Another part of the project I have been slowly working on is the tongue box and preliminary work on the electrical system.

Getting the components together.

Tongue Box progress.jpg (129.23 KiB) Viewed 1380 times

My new battery. 12V 75Ah AGM

Battery.jpg (45.84 KiB) Viewed 1380 times

[BLTillson]

Good morning teardrop and tiny trailer lovers.

It is encouraging to see how many people are looking at my build journal. I already feel that I am part of a bigger community.
Yesterday I had a good work day as I continued to work on the finicky fender assemblies. I long for the say (soon) when they will be installed and I can move on.

This is the final painted fender assembly.

Fender Final Painted.jpg (93.92 KiB) Viewed 1310 times

Fitted and almost ready to be finally attached.

Fender Fitting 2.jpg (165.6 KiB) Viewed 1310 times

Once the fenders and fender boxes are installed I can start working on what we call the header wall or the closet space between the bedroom and the galley.

[BLTillson]

Here are a couple of electrical progress pics.

I am working out the arrangement of the components in the tongue box. Things are getting a little tight but I am going to make my goal of two batteries, the converter, AC power in and battery cutoff switch. The rest will go inside.

Designing the tongue box pallet.

Tongue Box Power Pallet.jpg (178.57 KiB) Viewed 1309 times

Battery mount completed.

Battery Mounting 1.jpg (76.76 KiB) Viewed 1309 times

Battery mount detail.

Battery Mounting Detal.jpg (142.86 KiB) Viewed 1309 times

Just to note, I did make the mounts myself from 1" x 1" x 1/8" Aluminum angle.

[Graniterich]

One more thing:

I have been getting closer on solidifying the electrical system. Since 12v vehicle electrical started off as a mystery for me my confidence level is growing but not solid. Here is my latest schematic with more details of the wire gauges. I have changed from two 6v batteries to 12v. This is mostly due to cost. This was I can buy one 12v 50AH battery now and one later and connect them in parallel. Also, If I find that one 12v battery very inadequate, I can later change it out for two 6V batteries and not buy a second 12v. I think that made sense. Anyway, Here is my current schematic. I am open to and suggestions, corrections and opinions.

Trailer Electrical 12-22.jpg

I had a DROK, wasn't impressed. I use this, very happy
https://www.amazon.com/AiLi-Battery-Mon ... B07CTKYFTG


Sent from my KFTRWI using Tapatalk

[tony.latham]

I had a DROK, wasn't impressed. I use this, very happy
https://www.amazon.com/AiLi-Battery-Mon ... B07CTKYFTG

I, too vote for the AiLi meter. It'll tell you a LOT more.





Tony