Solar panel worry

[plople]

Hi, I have recently bought a motorhome with a solar panel and I ventured onto the roof to check this out to see if I can fit another solar panel on top of the van.

once I took a closer look I discovered the panel seems to have damage to the strips that run along the top of the panel.

I'm still getting a good charge from the panel and have had no issues keeping the batteries powered up but I'm worried this may degrade further and fail.

so my question is will this get worse and should I replace it with a larger panel or should I not worry and go with an extra panel saving money.

I've attached a picture of some of the panel.

TIA

[stevec176]

As the saying goes 'if it aint broke dont fix it'. While it's working leave alone but be prepared, look into the cost of a replacement now.

[plwsm2000]

I would also agree with the "if it ain't broke, don't fix it" comment.

 

All solar panels degrade over time. Many of the panels with "unbranded" cells will degrade by up to 2% per year so after 10 years, a 100W panel will behave like a 80W panel. 80% output may still give a useful amount of power though and might be good enough for your particular needs.

 

Your photo isn't very clear but there seems to be some corrosion on the metalised conductors. This may be normal (just poor quality) but I would look at them again in a few months to see if they have deteriorated further.

 

I wasn't sure if the round blots on the photo were just dirt on the glass or if the cell has overheated at some point due to partial shading (and lack of bypass diodes). This can be more serious and result in a sudden failure of the whole panel if it happens again. These areas would be discoloured (darker) if it has over heated.

 

If you are looking at a new panel, IMO you won't do much better than getting a panel made using Sunpower Maxeon Gen III solar cells. These are back contact cells so you do not see the metalised conductors at the front. Not only are these more efficient, they degrade far less than many other cells (0.3%/year) and don't need bypass diodes so the effects of partial shading is much reduced.

 

 

 

 

[Ocsid]

plwsm2000 - 2018-09-03 8:36 PM

All solar panels degrade over time. Many of the panels with "unbranded" cells will degrade by up to 2% per year so after 10 years, a 100W panel will behave like a 80W panel.

 

 

Interesting statement, one I have come across previously and being an owner of mine for 11 years poignant to me.

As someone who clearly knows a lot more on this subject than I, can you elaborate any more on this please?

 

Is the view, it is "time" as such or "time in use" or does the "level of power taken" each act as factors?

 

 

This summer I noted with interest my system apparently was pushing out just over its published 85 Watts rating.

Assuming this was its power by taking the simultaneous indicated Amps, and battery voltage readings.

 

My panel is an 85 Watt Kyocera with a Morningstar PWM Sun Seeker controller complete with their matching monitor.

It is a free standing job, living most of its life tucked away in a light sealed carrying cassette, though on site has been extensively used.

 

In our application considering those with fixed systems where in practice the battery(s) could be well topped up nearly all the time and so the controller placing near zero demand on the panel, for endless hours. Are these then minimal "loads" placed on the panel actually eating that much into the panels life?

[plwsm2000]

Ocsid - 2018-09-04 7:07 AM

 

plwsm2000 - 2018-09-03 8:36 PM

All solar panels degrade over time. Many of the panels with "unbranded" cells will degrade by up to 2% per year so after 10 years, a 100W panel will behave like a 80W panel.

 

 

Interesting statement, one I have come across previously and being an owner of mine for 11 years poignant to me.

As someone who clearly knows a lot more on this subject than I, can you elaborate any more on this please?

 

Is the view, it is "time" as such or "time in use" or does the "level of power taken" each act as factors?

 

Firstly, I do not regard myself as an expert in this field but I do like to read (and try to understand) technical articles so my comments are more from this "knowledge" rather than from extensive experience. That said, I am fairly good at recognising technical BS that is sometimes (IMO) written just to confuse people.

 

There are many factors that affect the life of solar panels - the dominant factors are related to the actual cells that make up the panel and others due to how the panel is assembled.

 

One of the biggest factors is humidity. Water vapour will very slowly diffuse through the back of the panel which is usually made from plastics like EVA. Over time, this forms acetic acid that will weaken the contact bonds and their ability to carry current. This degrades the output over time. One of the reason why I like the idea of the Sunpower cells is that they use back contacts.These can be coated with various materials to protect against moisture without affecting the performance of the cell. Most other cells have contacts both sides so the "sunny side" cannot be coated too much without affecting its output.

 

Some of the materials used in the construction will "yellow" over time and therefore reduce its output.

Other factors such as light induced degradation (LID), Potential induced degradation (PID) can be unique to certain cells and panels sizes.

 

It is worth stating that although there are many factors involved, their combined affects are usually still quite small for the majority of decent quality panels. Due to the variability of sun light on a day-by-day, minute-by-minute basis, most people probably won't notice that the panel has degraded until it fails totally.

 

So to finally answer your question, the degradation is mainly caused by sunlight and humidity, rather than how much or little power you take out of the panel.

The only possible exception is if the panel is partially shaded and you try to draw lots of power from it. The shaded cells can overheat as they dissipate some of the power the panel is producing and will degrade faster.

 

 

 

 

Ocsid - 2018-09-04 7:07 AM

 

This summer I noted with interest my system apparently was pushing out just over its published 85 Watts rating.

Assuming this was its power by taking the simultaneous indicated Amps, and battery voltage readings.

 

My panel is an 85 Watt Kyocera with a Morningstar PWM Sun Seeker controller complete with their matching monitor.

It is a free standing job, living most of its life tucked away in a light sealed carrying cassette, though on site has been extensively used.

 

A free standing panel can actually produce a little bit more power that its publish rating under certain conditions.

Decent manufactures (and I include Kyocera in that class), often underrate their panels to account for variabilities and include a safety margin. My panel was sold as a 110W, but if you multiply the individuals cells output by the number of cells, it should be 116W. With a +/-3% tolerance, it could even be 120W.

 

If it faces directly at the sun (perpendicular) rather than facing straight up if mounted on the roof, it will get the maximum exposure.

Panels are usually rated at "STC" (standard test conditions) which is 1000W/m^2, AM 1.5g and 25degC. The Air Mass of 1.5 is for typical atmospheric condition and assumes a certain level of water vapour, ozone levels and turbidity. On a particularly clear, dry day, the actual AM may be less that 1.5 so the suns rays will not be absorbed by the atmosphere as much, meaning more power on the panel.

There is likely to be more air flow around a free standing panel that one that is mounted on a roof with a small airgap underneath it. This will also help its output.

 

 

 

Ocsid - 2018-09-04 7:07 AM

In our application considering those with fixed systems where in practice the battery(s) could be well topped up nearly all the time and so the controller placing near zero demand on the panel, for endless hours. Are these then minimal "loads" placed on the panel actually eating that much into the panels life?

 

As mentioned above, taking minimal power from the panel does not affect its life. If you really want to preserve a panel's life, keep it dry and covered up (somewhat easier to do with a free standing panel than one mounted on your roof)

[aandncaravan]

Plwsm2000, that is an excellent post and more informative than any other I have read.

Like it.

 

May I please add it to our Solar webpages, I will credit you and you have full control on content, now and future?

 

 

[plwsm2000]

Allan,

Thanks for the compliment.

 

I have no problem with you using any of this. The only think I would say is that the reason why I sounded a bit like a salesman for Sunpower, is that many of my comments are based on what Sunpower have published on their website and I have not been able to find much information on other manufacturers cells. This in itself may say something as I don't understand why manufacturers would not make a song and dance about their technical advantages?

 

I found this article particular interesting [url=] https://us.sunpower.com/sites/sunpower/files/media-library/white-papers/wp-sunpower-module-degradation-rate.pdf [/url]

 

Incidentally, a big German manufacturer Solar World, went bust a few months ago (mainly due to competition with the cheap Chinese imports). It seems a bit unfair for companies like this who invest heavily in R&D and hi tech manufacturing while other companies just copy the technology. Makes you wonder where this is all heading. Not sure how it leaves those 25+ year warranties either.

 

[monique.hubrechtsgm]

The most important of solar is that you check regulary that it is really charging your batteries. They are designed for the sun. Mostly flat on a RV vehicle,regarding degrading. The angle of attack is a factor.

[Paul-]

Ocsid - 2018-09-04 7:07 AM

 

plwsm2000 - 2018-09-03 8:36 PM

All solar panels degrade over time. Many of the panels with "unbranded" cells will degrade by up to 2% per year so after 10 years, a 100W panel will behave like a 80W panel.

 

 

Interesting statement, one I have come across previously and being an owner of mine for 11 years poignant to me.

As someone who clearly knows a lot more on this subject than I, can you elaborate any more on this please?

 

Is the view, it is "time" as such or "time in use" or does the "level of power taken" each act as factors?

 

 

This summer I noted with interest my system apparently was pushing out just over its published 85 Watts rating.

Assuming this was its power by taking the simultaneous indicated Amps, and battery voltage readings.

 

My panel is an 85 Watt Kyocera with a Morningstar PWM Sun Seeker controller complete with their matching monitor.

It is a free standing job, living most of its life tucked away in a light sealed carrying cassette, though on site has been extensively used.

 

In our application considering those with fixed systems where in practice the battery(s) could be well topped up nearly all the time and so the controller placing near zero demand on the panel, for endless hours. Are these then minimal "loads" placed on the panel actually eating that much into the panels life?

 

You have a good combination

Kyocera make very high quality panels with exceptionally low age related power loss, the same type of quality can be said for Morningstar in relation to their controllers, however if you have doubts and want to improve the set up, I think their SunSaver controller positioned close to the battery in a ventilated position would give you better results than your SunSeaker controller.

 

 

[aandncaravan]

Plwsm2000, Thank you for the link to that Solar panel web page, I had no idea just how many different factors affect Solar Panel life and the importance that a quality manufacturer might make to the difference between 5 years useful life and 20.

 

Having seen so many panels dead before 10 years are up and lots under performing way before that time I was surprised that Ocsid's 11 year old, 80w panel was still delivering peak power.

But when I read 'your' link, it was obvious that, because Ocsid's panel was a 'foldaway' and kept stored dry, it would have a more useful and longer life.

 

 

I have added that link to the website and credited you, but using your Out and About id, see :

http://www.aandncaravanservices.co.uk/solar-panels.php

 

If you want me to add you real name, then please PM me.

 

Thank you

[weldted]

Re the last post from aandncaravan. I have just removed a Solar boost 2000E the same as the one described. This was purchased in Dec 2007 together with 2 90 watt mono panels. 3, 40 watt panels were added in 2011. This set up has been transferred twice and was fitted to our current van in 2012. As it only had a single output and I used a battery mate to top up the engine battery and given technology has moved on I decided to upgrade my system with somewhat dissapointing results. Having fitted a Votronic 350 mpp controller with a second output for the engine battery together with a Solar computer and shunt, 2 new Youasa L36-EFB 100 amp batteries I now find I am getting a lower charge rate than before. The batteries have had ten or twelve light discharges so should be working up to their peak efficiency they were on mains hook up for 3 days with a new Victron smart blue tooth 15/30 charger. That was ten days ago, I have noticed a considerable reduction in the amount of charge going to the batteries. Even with normal overnight use the input is at best down by 30% against the original set up. I am well aware that the weather and time of year will reduce the available sunlight but having had the system for over ten years am fairly used to how it performs.

[plwsm2000]

weldted - 2018-09-10 6:53 AM

 

Re the last post from aandncaravan. I have just removed a Solar boost 2000E the same as the one described. This was purchased in Dec 2007 together with 2 90 watt mono panels. 3, 40 watt panels were added in 2011. This set up has been transferred twice and was fitted to our current van in 2012. As it only had a single output and I used a battery mate to top up the engine battery and given technology has moved on I decided to upgrade my system with somewhat dissapointing results. Having fitted a Votronic 350 mpp controller with a second output for the engine battery together with a Solar computer and shunt, 2 new Youasa L36-EFB 100 amp batteries I now find I am getting a lower charge rate than before. The batteries have had ten or twelve light discharges so should be working up to their peak efficiency they were on mains hook up for 3 days with a new Victron smart blue tooth 15/30 charger. That was ten days ago, I have noticed a considerable reduction in the amount of charge going to the batteries. Even with normal overnight use the input is at best down by 30% against the original set up. I am well aware that the weather and time of year will reduce the available sunlight but having had the system for over ten years am fairly used to how it performs.

 

I can think of a few possibilities that might explain an apparent drop in output.

Obviously it is difficult to compare solar outputs at different times as the amount of solar energy available varies considerably.

 

Is it possible that your new EHU charger is doing a better job at charging the batteries? (so the solar charger doesn't need to work as hard?)

 

I notice that your old 2000E was also an MPPT charger. There are 4 or 5 different methods (algorithms) of implementing the MPPT function and they may behave slightly differently to each other depending on the various conditions. Unfortunately, it is not a simple case of one is better than another because if the conditions change (i.e temperature, shading, how fast the solar energy changes etc), another algorithm may be better than the first. I don't know what algorithm is used in the 2000E or the Votronic but if they are different, you may see a small difference in the available power.

 

Are the panels connected properly and working ok? If all 5 panels are connected in parallel, if one panel stops working you would obviously see a significant drop in output from the array. How are your 2x90W and 3x40W panels connected (including any blocking diodes).

 

Also are the panels output voltage matched to each other? If not, the MPPT tracking may not be as good as it could be. If you have mismatched voltages, the shape of the power curve may not have a "clean" peak so the MPPT algorithm may not find the optimum operating point. Badly mismatched panels give you other problems too.

 

Another possibility is the length of the main/full charge set on the solar regulator (battery dependent). On the Votronic, the "lead acid" setting gives 14.4V for between 0.5 and 4 hours before going into a 13.8V float charge. I don't know what the 2000E does.

The Votronic starts up when the voltage on the solar panels reaches about 14V. I don't know at what point the main/full charge timer starts running so I assume it starts immediately.

A possible problem I can see with this is that there is not much power in the sun in early morning. As the battery will be demanding maximum solar current following its overnight use, there won't be enough solar energy available before the timer runs out and the regulator goes into its float charge.

On mid summers day in the south of the UK, the sun rises just before 5am so before 9am, the regulator will switch into its float charge. Obviously you won't get much power from the "main" charge, so it would be nice if the regulator holds off this timer until there is a reasonable amount of power available. I have tried unsuccessfully to clarify this point with Votronic but I'll have another go.

The 2000E may behave differently in this respect.

 

The first thing I would rule out if I were you is to check that each panel is working normally. Either connect them up individually or if it is easier, cover 4 of them up (leaving just one uncovered) and check each one separately.

 

 

 

 

 

 

 

[aandncaravan]

I agree with the above assessment but would also add that you have just fitted two new very efficient batteries that won't need, or draw, so much charge. They won't pull any power if they are "full".

 

There can easily be 30% difference between the best and worst batteries when new.

Add into the equation that your old ones were not new, possibly corroded, tired and with a higher self drain when the sun goes down, etc.

Not hard to imagine a 50% reduction in the power needed, solely through less wasted 12v power.

 

I would expect a big drop in charging of your batteries, because the Yuasa L36-EFB is so very good.

 

 

I think I say above somewhere in the 'Yet another battery question' thread, that running poor quality, old batteries is like driving around with 50% of the Solar Panel covered with a blanket, and it really is.

 

If you look at the graphic below you will see the corrosion/Grid growth that builds up between the Grid and the 'Active Paste'. All your electricity has to fight it's way through that that crud, both to get into the battery, and get out again. You can see why the photo on the right might allow Varta/Bosch claim a 70% better electrical flow?

You have probably gone from batteries like on the left to those on the right so a 70% improvement is something you will really notice. I think the setup working a whole lot less hard is a good sign.

 

 

 

If you want to test the max output of the panel you need to "take the batteries out of the equation" and put on a high electrical load, just slightly more than that which the Solar setup can achieve, and then monitor over a day or two.

 

The difference between what you can max out of the panels and what you now use each day will be your contingency.

 

[Paul-]

The general rule is, if connected in parallel the volts on each panel should be the same, if in series the watts on each panel should be the same.

 

[plwsm2000]

Paul- - 2018-09-13 7:36 PM

 

The general rule is, if connected in parallel the volts on each panel should be the same, if in series the watts on each panel should be the same.

 

Paul.

I think you meant to say "..if connected in series, the CURRENT of each panel should be the same"

[EMS]

It will be interesting too see the cost of solar panels in the near future as the EU has just permitted the importation without restriction of solar panels from China.

The logic is based on the commercial installations of solar panels not for motorhomes or vans, more people will be employed installing solar panels on houses and the like than manufacturing them.

So a win for the ecological groups reducing the use of fossil fuels in europe.