UKH

Hi

Has anyone put solar panels on their van?

I'm looking into it, and can't decide between a rigid one (heavy, more reliable?, don't have to stick to roof) vs a flexible one (lighter, stick to roof so pain if it fails).

has anyone got any experience of either? cheers!

The flexible ones are quite prone to overheating, which reduces the amperage they can generate in direct sun.  I found this a problem on mine when in europe (i.e. more southerly latitudes than our fair land).  In hindsight I would go with a rigid panel, they're generally going to provide a more reliable output. 

It does depend on how reliant you will be on the solar - if its just to keep the leisure batteries topped up, flexible is ok. If you're relying on it for a few days at a time to keep everything working, go rigid, and go for as much quality and watts as you can afford!

Thanks! Yep, it's for topping up battery.

Tempted by flexible, just getting a bit put off by every blog I've read in which they rave about the flexible panels then featuring a follow-up post saying they've ripped them off and replaced them with a fixed panel! Oh well!

I went with a rigid 40v domestic panel, with MPPT controller for efficiency. Several years of full timing later I'm still happy with my choice. BimbleSolar do some great deals on domestic panels, if you can wait for their delivery schedule. 

Best to bond the brackets to the roof IMO, so you don't create holes except for the cable entry box. Does make them a right pain to remove of you ever want to though

Another vote for bimble solar. I bought a rigid 210w panel (+ charge controller etc.) from them 3 years ago and haven't had any problems with it.

Weight wasn't a problem, think the panel on it's own is about 20kg? Just get a friend to help you get it on to the roof if you're not happy doing it on your own.

I made some little brackets to attach it to the roof of the van. Used some big rubber washers and a load of sealant to keep everything waterproof. No leaks so far.

Thanks guys, hadn’t seen Bimble Solar, they look good will go and check them out...

There’s a kind of self sealing bolt you can use to go through sheet metal roofs for the semi-flexible panels. I can’t remember their proper name but an example is “motorcycle windshield bolts”.

If you’re new to auto electrics be sure to read this handy guide to circuit protection - https://www.12voltplanet.co.uk/fuses-guide-uses.html - there’s no real point in fusing the panel itself.  Sorry if you know all this stuff!

Flexible ones stuck directly to the roof fail.

I've killed 8 so far.

If you do decide to go that way, I strongly suggest you avoid eBay and pay a little more for some distributed by a UK company so you have some sort of comeback.

Beware of sticking rigid panels to the roof.  The holding power is only as strong as bond of the top coat of paint to the roof .  We have all seen the top layer of lacquer come off some panels due to lack of adhesion. There have been some case's of large panels coming adrift while on the move. Always use proper bolts with the right sealant.

It's a subject that gets a lot of posts on the VW Forums, 4 pager here with lots of good advice, i have thought about it and think roof bars and rigid is the way to go for best performance and reliability

https://www.vwt4forum.co.uk/showthread.php?t=1570850

Thanks all, super useful!

Flexi glued on pop top, no bolts or screws. A rigid is not a beauty or aerodynamic. 80 watt to top up 120 amp hour domestic battery.

Bought from a company that supplied the glue and the panel and said it would stick. You would struggle to shift it. 

Ours will beat the fridge in hot weather. 

Big point is output from these panels is almost infinitely higher in summer than winter so averages are useless. 

For taking the cables through the roof look at yacht 'deck glands' , much cuter than the stuff sold for campers. 

If you want a decent adhesive / sealant then use sikaflex 291. Be warned about 2 of its properties though:-

1) it multiplies. Get a blob on the van and try to wipe it off with a finger. You now somehow seem to have the same amount on your van plus the same amount on your finger...!

2) It's unremoveable, to the point that boatbuilding books say not to use it for bedding in seawater inlets as you can't do anything to them without destroying either the inlet or the hull you've bonded it to.

... and when you buy one, make sure it is coming from the UK. They are sizable things to be sending back overseas if they are not correct for whatever reason. e.g. Sunworks.co.uk is in France. 

I’ve got a flexible one, fine for what it is and gives you a bit more off-mains time.  Keeps the battery it’s attached to fully charged even on a winter’s day in the uk, but.... as I found out when trying to work from the road, running the fridge, lights, computer etc will still drain stored power faster than it can be replenished. 

When I put roof rails on my t4 elevating roof I realised I could fit a solar panel without worrying about how to fit the panel itself to the roof.

i initially fitted a flexible 50w panel and 10 mppt controller but this proved to be insufficient for keeping the battery topped up in usual lakes conditions.

i fitted additional 110a leisure battery and just fitted new rigid 120w panel which is a massive improvement in cloudy conditions. 

Mom me if you like for photos. All kit bought from photonic universe who were pretty helpful. 

I've used 2 110W flexible panels. Firstly some cheap chinese ones that failed and now some German ones. 

Rigid are much cheaper and about 30% more efficient as they can cool much better.

Flexible are mainly only beneficial for cosmetic purposes and perhaps if using roof bars etc...

If using flexible first mount a Dibond panel as it'll give a flat mounting surface and will help prevent work hardening of contact's within the panel, it'll also make removing the panel easier of it ever fails.

220W of flexible 22V panels, 2 6V traction batteries wired in series and a Ctek d250s with a smart pass keeps us off grid. But we only run a compressor fridge. (Dometic CRX50) lights, chargers and a 150W inverter for charging laptop and a speaker.

This it what we used https://sunworks.co.uk/product/semi-flexible-solar-panel-110-watts/ the brand is Wattstunde.

I went for a flexible panel because I wanted to still be able to get under a standard 2.1m height restriction and a rigid panel was too fat. I glued it to a sheet of aluminium and mounted it on hinges so that I can tilt it towards the sun. This has come in handy a couple of times when I've been at a festival for several nights and couldn't park with the panels facing the sun. I used a Bimble solar 145W. The most I've seen out of it is about 80W, but it's sufficient to run my fridge, pump, heater etc. 

I don't know how applicable this will turn out to be to solar panels, but at some point in my 20's I decided to start listening to the advice of people around me for an easier life, when it came from experience or what seemed to be 'universal truths', and it did pay off. 

Another vote for Bimble. I used them a few years ago for a rigid panel and accoutrements for a narrowboat. Very competitively priced, and very good to deal with.

Do you actually need it? If you’re driving fairly regularly (say every 3 days) or staying on sites you don’t. 

Thanks everyone, even more great info, especially about Diabond panel.  

(Yep, I'm not 100% sure I need it either, but if you want a fridge then it seems like a good way to go.)

I have a fridge which lasts (along with everything else) about 2-3 days on 2x 100Ah batteries

72 hrs @ 1.5a/hr is 108a (estimate) which is about ok for 2 x 100a batteries but I think it would depend on how often you are doing it and how long you need to drive to fully charge them up. If your alternator through the split load relay is delivering 6a that’s a long run and not just from one valley to another.

well done for managing it but I’ve not been able to, maybe I’ve just had crap leisure batteries but I have killed 2 by over the years discharging them while forgetting to switch off any power drains etc. 

So, it was a major expense not taken lightly but even if it saves 2 batteries it’s paid for itself eventually and I don’t need the hassle of the guy next to me last week who spoiled the peace running his engine for what seemed 2 hours a day. 

Hmmm, not so simple. If you run a leisure gel type battery down to say 10.5v, it takes up to 3 days of continuous charge to bring it back. If you just drive 10 miles or so the volts will jump to 13.2 ish but it is not an accurate view of the state of charge. If you then run the battery down again and repeat for a few days you will have a dead battery.

We switch the fridge off if volts drop below 12.4.

Or use a LPG powered fridge....

We found that the lpg powered fridges don't work very well when the temperature is in the 30s, plus you get through a lot of gas.

Well it’s that simple for us and we spend a lot of time away in the van. After 2-3 days batteries are down to 12.1 usually which is fine. They’ve been in use for years. I’m not saying park up for 3 days drive for 10 minutes and repeat because obviously that wouldn’t work

Fair enough. Out of interest how many battery amp hours do you have and what wattage of fridge or ampage?