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Does anyone have reasonably long-term experience of flexible panels on vehicles?

There are a lot of different panel types out there, of varying robustness. Numerous tales of failed panels, but also some happy customers.

I have a camper (with an almost flat, but ribbed, pop-top roof), and am wading through the info I can find trying to pick a panel/setup. But it's a bit of a minefield so actual experience of stuff that worked (or didn't) would be helpful.

I do know of some flex-panels which have been given a mechanically quite hard life, and frozen/cooked for 17 years, which are still working fine so they are not _all_ crap. Sadly those panels were acquired s/h (but unused) and don't have a label, so we don't actually know what manufacturer/model they are. State-of the art in late 2006 I think, probabaly CIGS.

CIGS panels are much more flexible, and robust, but there are still some which have delaminated outside desert environments (e.g. Rich Solar in the US, which put the generally-sensible Will Prowse off all flex panels for life but that appears to be an over-reaction). BIPVco's panels still require support between ribs (e.g. using foamex).

Mono-crystalline panels are very prone to cracking (because the cell is basically glass and only flexible at all because it's very thin). Various designs are varying flex-radiuses, some only bend at all in one axis, and there is a lot of talk in the instructions about careful handling before installation to avoid flexing too much/in the wrong direction/more than once. But I suspect that if you can get them on without cracking them, especially onto an almost planar surface, with adequate support between ribs and enough glue so that there is no significant movement when driving about, that the cheaper mono panels can have reasonable lifetimes. But I don't know this for sure so would like to hear of success stories. Maybe they always end up cracking and then you have a useless panel glued down so well that you will damage the roof getting it off?

We had a 100W stick on panel on our Mazda Bongo for around 5 years. Worked well, no complaints. I think we bought it from Ebay along with an inexpensive pwm controller and there was a 500W inverter already fitted with an 80Ah LB. It worked well enough as a system but didn't have the raw horsepower to keep up with our fridge so we'd be running it down too often.

Second pass on the new van has been two 195W bifacial panels and a Victron controller along with a 1kW inverter.

Being able to compare the two set ups the most obvious difference is speed of recovery on the LB with the mppt and bigger array. Also the lack of drain on the LB due to the momentary power being generated by the PV is also apparent.

Going bigger means we can run a 0.75ltr travel kettle, induction hob or small oven. In the old set up I was relying on gas or an electric hookup.

I'd advise a Victron charge controller for their robust build and high efficiency and as much panel as you can fit. With hindsight 200W is minimum I'd try with but preferably more.

With the old setup we were getting by, With the new setup we are getting on.

It was this style
https://www.ebay.co.uk/itm/235987073940 ... media=COPY

We also bought and installed a small 12V panel to keep the starter battery topped up. We had these in the Bongo too and they do make a difference.

My only experience of flexible panels are thin film types: I have a Unisolar 32w rollable panel that must be 20 years old by now (don't think they make them anymore): water and air have gotten into it and it doesn't lie flat anymore due to air & kinks and creases; but it still works fine if i need a remote battery charger, and is very shadow tolerant due to each of it's eleven cells having its own bypass diode.

I have no experience of the mono/polycrystalline 'flexible' panels, (just to be a pedant: they are crystalline Si, not glass (amorphous SiO2) or quartz (crystalline SiO2 (I think). But yes, the cells are VERY brittle, and IIRC, they were sold as flexible so "could be fitted to a curve roof or boat deck and you can walk on them": fit to a curved surface, perhaps; walk on them, no! I suspect the mis-selling is part of their bad reputation).

Joeboy wrote: ↑Sat Apr 19, 2025 1:46 pm We had a 100W stick on panel on our Mazda Bongo for around 5 years. Worked well, no complaints.

OK, good to hear those panels _can_ last for a reasonable period of time.

I'd advise a Victron charge controller for their robust build and high efficiency and as much panel as you can fit. With hindsight 200W is minimum I'd try with but preferably more.

Yes, a Victron MPPT is the plan. Having picked Victron at home, it makes a lot of sense to put it in the van too. It will add monitoring and logging as well as efficiency/utilisation. A 100/20 that does up to 290W is only £55. But the next size 100/30 is nearly double at £109 which stings a bit more. I can get more than 290W on the roof, but it gets expensive so (as I plan to only own this van for a couple of years) I might see how 270-290W works out.

wookey wrote: ↑Sun Apr 20, 2025 2:41 am

Joeboy wrote: ↑Sat Apr 19, 2025 1:46 pm We had a 100W stick on panel on our Mazda Bongo for around 5 years. Worked well, no complaints.

OK, good to hear those panels _can_ last for a reasonable period of time.

I'd advise a Victron charge controller for their robust build and high efficiency and as much panel as you can fit. With hindsight 200W is minimum I'd try with but preferably more.

Yes, a Victron MPPT is the plan. Having picked Victron at home, it makes a lot of sense to put it in the van too. It will add monitoring and logging as well as efficiency/utilisation. A 100/20 that does up to 290W is only £55. But the next size 100/30 is nearly double at £109 which stings a bit more. I can get more than 290W on the roof, but it gets expensive so (as I plan to only own this van for a couple of years) I might see how 270-290W works out.

I guess it all depends on what you want to run and for how long? I am bringing a couple of big 5V battery packs back from Turkey next month so we always have phone & light charging capability.

Scenario, we run the LB fully down somehow. It will be good to have a few days charging cap for phones, radio etc if it's dull.

With hindsight, I bought the Bongo at 48 and sold a few months back so a little under 8 years with the mono panel in place. It had an annual clean. No signs of cracks and was outputting well when the new owner drove away. The efficiency on the mono flex has risen well over the years too.

There is a pretty standard pass through available on Ebay etc. Stick it down with CT1 and forget.

I also had a flexible panel fitted to my previous van for the last 5 years. It was fitted to my transit custom using tiger seal & worked a treat.
80W panel plus mppt and a 130Ah lead acid leisure battery ran our fridge, lights, USB chargers etc perfectly.

For my new van I will go bigger though, rigid panel(s) fixed to a roof rack and an LFP battery

Weve used flexipanels on all of the boats we have owned. They have been fine sitting with saltwater spray, acidic seagull droppings and battered by every weather type known to man. The wiring has failed before the panels did on the two we had to replace.
Only smaller panels each time. 50W to keep batteries charged, but all relative.
The current one has been on the wheelhouse roof for at least 10 years, its yellowing now, but still working fine.

All have been non descript ebay affairs.