Starting a home build FG and looking for lots of advice.

A

Alastair D(Aus)

aging but active
solar panels

I have 6 x 100w panels on my roof. Each one is 7.5kg and the Al frame etc maybe makes it ~8kg. So I have 600w and ~50Kg spread over my roof. I don't think that load is a problem and I have room for 2 more panels if needed. So far they are working really well with my LFP battery system through a Victron 75/50 MPPT requlator. We also use an induction cooktop and I am now rethinking the installation of a Webasto dual top in favour of a 12/240v electric HW system due to weight and space etc. Will post my thinking soon.
 
1

1aquaholic

Adventurer
Wow close to a thousand dollars for 100w for the Solbian panels, between that and thousands for lithium batteries we are talking 20 grand. Very hard to justify....

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D

DzlToy

Explorer
^^ So is a 500K Earthroamer or a 250K Earthcruiser, but somehow they seem to be flying off the shelves....

If I were building a custom rig, I would consider the high quality solar and high quality Lithium to be an investment that will pay for itself over time, as opposed to buying lead acid or inferior solar panels for less $$. The upfront cost may be tough to swallow, but they should pay for themselves in the long run if you are going to spend a decent amount of time off the grid.
 
SkiFreak

SkiFreak

Crazy Person
As much as UniSolar has been defunked for a few years now, some of these well known and proven panels are still available, and at a pretty reasonable price.
i recently purchased 680 watts for a thousand bucks.
 
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LeishaShannon

Adventurer
Unisolar are great if you plan to park in partial shade, but after 12 months full time travel I could count on one hand the number of times that has happened.

They require 4 times as much roof space as a decent mono-crystalline rigid panel like the LG Neon Black or Sunpower X22, or put another way you can generate 4x as much power for the same roof space using quality grid-connect residential panels.

Any weight advantage of Unisolar panels is soon lost once you devise a method for mounting them above the camper, which is recommended for optimal solar performance and for reducing the heat inside.

Eg. 136W Unisolar = 7.7Kg (5.66Kg/100W) , 360W Sunpower = 18.6Kg ( 5.16K g/ 100W) , 100W Solbian ( 1.5Kg/100W)

Paying a premium for panels which weigh more, require 4x as much roof space, but may perform better when partially shaded doesn't stack up for me. (Hint - when you have 4x higher W/m2 , the partial shading performance is rarely an issue)

The flexible Solbian panels are lighter, but you still need to devise a method to mount them above the roof unless you want the inside of your camper to cook... think about the effect inside of painting your roof black.

FLIR0100_1.jpg

Thats what the thermal camera saw when I left a packet of black cable ties on my roof (35mm HD PU foam insulation)

Its hard to go past decent grid-tie rigid panels as they're miles ahead in efficiency (34% ahead of Solbian and 400% ahead of Unisolar) , cheaper, and easier to mount above the roof.
 
whatcharterboat

whatcharterboat

Supporting Sponsor, Overland Certified OC0018
LeishaShannon said:
Any weight advantage of Unisolar panels is soon lost once you devise a method for mounting them above the camper, which is recommended for optimal solar performance and for reducing the heat inside.

Paying a premium for panels which weigh more, require 4x as much roof space, but may perform better when partially shaded doesn't stack up for me. (Hint - when you have 4x higher W/m2 , the partial shading performance is rarely an issue)

......... as they're miles ahead in efficiency (34% ahead of Solbian and 400% ahead of Unisolar) , cheaper, and easier to mount above the roof.
Click to expand...

Hi Shannon,

Just wanted to throw my 2 cents in.
.
Firstly regarding Unisolar panels being recommended "mounted above the camper". I've never heard this before. As you know thermal efficiency of solar panels drops off with high temperatures .... the term for this is called "Cell Temp Derating" and exact figures for how much an individual panel is effected must be specified on each panel. As you know, the reason panels are recommended to be mounted above a camper is to allow some airflow underneath in an attempt to reduce surface cell temperatures above. Monocrystalline panels are typically the most effected by this with polycrystralline panels almost as bad. Cell temp derating figures for Unisolar and typical amorphous panels are virtually nil. Not sure if you knew that but mounting a Unisolar flat on the roof as intended or mounting it above the camper will make virtually no difference to the performance.......I could almost argue that in this respect a Unisolar panel is 500% more efficient than a Monocrystalline. Hahaha.
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The main reason I am such a fan of the Unisolar panels is the amount of watt/hours a day they punch out. Monos and polys need to be tilted to the sun angle for maximum performance. Amorphous not so much.(Starting to sound like Owen. Scary) Anyway we did a lot of testing years back measuring total watt/hours a day from various panels laying flat. At low sun angles the Unisolar kept pumping the power in long after the monos had gone to sleep. So efficiency figures stated for various panels means bugger all to me. The only time I would ever take "efficiency" into account is if space was at an absolute premium .... like a yacht and then sure, a Monocrystalline would usually win out.....but then tilting arrays mounted on a rail in the breeze behind the cockpit solve a lot of issues. As for a truck camper , if you only reguire 280watts of Unisolar and have the room for it, then does "efficiency" come in to it??? Especially when you could argue that 280watts of the most "efficient" monocrystalline panels (based only on the power output per square metre) can actually produce less power over the whole day due to the poorer performance at lower sun angles and high cell temps than 280watts of Unisolar.
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When we were taught at college to calculate stand alone solar power systems >> for monocrystalline and polycrystalline solar panels not tilted to the sun angle and laying flat , you would subtract 20% from the rated power output. So a 100Watt panel would come back to 80W x Peak Sun Hours = W/hrs a day ....then we would factor in cell temp derating, soil derating, etc..... that sort of throws given efficiency figures into dispute right there.
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One of the other reasons I used to like the Unisolar was their performance under partial shading but not for the same reasons as you mentioned.....I found they were so tough you could throw gear up on the roof occasionally like fishing rods, surfboards, etc and as long as the panels was not completely covered, they would still put out some thing. They were pretty tough things that you could walk around on too. A shame they went off the market....but they certainly could never compete in the grid-tie market.
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Shannon, of course you make a very valid point about the effect of stick-on panels heating the cabin ceiling.
Kind regards John.
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LeishaShannon

Adventurer
Apologises if it wasn't clear - the comment about mounting (any) panels above the camper was to reduce the heat transferred inside. I wouldn't want anything dark stuck to my roof after seeing that thermal image! I realise the UniSolar panels aren't as affected by temperature as the monos.

Our LG Neons use double sided cells - they produce energy from both the front and back of the cells which improves the low light / low incident angle performance compared to "normal" mono panels. The typical daily output curve has quite steep sides and a fairly flat top - its generating 80% of the output just after 9am and starts to drop off after 3pm.

These aren't your average 12v "RV" panels made with B grade cells, Sunpower claim their panels will produce 21% more energy per rated watt than a standard mono-crystalline.

From the 1200W installed on ~7m2 of roof space we generate upwards of 8kWh/day, I can't see ~420W of UniSolar getting close to that output but it'd be interesting to compare them side by side.. Hurry up and finish your truck Owen! ;)
 
gait

gait

Explorer
I've just (yesterday) replaced 590W of 8 year old Kyocera panels with 1160W of nominal 24v poly panels. Memories of childhood tesselations. Roof is about 4x2m.

The old panels will go to daughter's off-grid install where space doesn't matter. New panels have a spec'd 25% higher W/m2 for same solar conditions. Technical evolution.

I've stuck with MPPT. Figures with old panels and new batteries on a good solar day show above 10% energy (Wh/day) due to mppt when batteries below 100% SOC at end of day. That will be about 7% of battery capacity with new panels.

Unlike Shannon I've spent lots of days in the last three months under trees (in national parks) as well as in the middle of my daughter's treeless field. The lack of panels made a big difference.

I knew when I changed from AGM to Li and diesel cooking to induction I would need more solar. All part of the plan.

On the control front I'm using an Arduino for BMS. Yet to do, my inverter has a remote switch which I will be able to drive from Arduino for low volts cutout. The extension of that is to turn a second inverter on/off for hot water when there is excess solar - my calorifier has 240v coil. In turn that will reduce the load on the induction and effectively increase energy storage - its become easier to boil the kettle than use the diesel hot water heater - about 350Wh to heat 10 litres water from 20 to 50 deg C.

Its taking a while and there's a long way to go but solar is slowly coming of age.

I happen to be around Canberra at the moment - away from home. Owen has been very generous with time and facilities. I haven't convinced him to sell me his unisolar panels, but haven't tried.
 
1

1aquaholic

Adventurer
Well life sidetracks you sometimes, haven't gotten nearly as much done as I'd hoped and never motivated enough to post my progress so here's a little video. Will try and do another to show what the wireless airbag control and self leveling can do, very happy with it. Any questions ask and I'll try and answer soon.

https://youtu.be/gA8dRMIXJsc

Sent from my SM-G955U using Tapatalk
 
1

1aquaholic

Adventurer
No nothing underneath, HNR on the floor on the inside which is a sound deadener, I wish I would have spent a little more time and put a couple more coats of that on. Then I spray in bedliner over that and sound deaden the walls and ceiling I was pretty meticulous about putting it on and the results are dramatic. I'd guess about a 75% reduction in sound if not more. The mirrors are now the noisiest part of the rig and I want to change them out anyway just trying to figure out how to custom do that.

It was a lot of work but I think it was worth it.

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J
 
D

DzlToy

Explorer
1aquaholic said:
The mirrors are now the noisiest part of the rig and I want to change them out anyway just trying to figure out how to custom do that.
Click to expand...

good quality back up cameras mounted in an aerodynamic pod on the door and piped to an in dash monitor.

It is being done on commercial trucks, as recently demonstrated at a commercial vehicle trade show that I attended.

Towing mirrors from a half ton or 3/4 ton pickup would be a much better choice than the factory FE mirrors, they are terrible IMO.

If you fancy a roof mounted option, look at the large motorhomes and touring coaches (SETRA, Volvo, Prevost, etc)
 
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