Are these Solar Panels any good?

[junior]

I'm about to purchase a couple of solar panels. Due to restrictions in space and the fact that i don't want to change the profile of the boat (yet), i've decided to go with flexible/semi-flexible.

 

With some of the more popular solar panel retailers, these semi-flexible panels cost a fortune (£300+) for a 100w panel. I've found these on eBay for a much more affordable price, but as i'm no expert with solar or electrics i wondered if anybody could spot a flaw with my plan. Either that they are crap panels, or that they wouldn't be suitable for a boat solar system etc. Or indeed the seller looks like a con-artist.

 

http://www.ebay.co.uk/itm/NEW-100W-12v-Energy-Semi-Flexible-Solar-Panel-Monocrystalline-TUV-ISO-UK-/251328916630?pt=UK_Gadgets&hash=item3a845eec96#ht_3802wt_932

 

 

http://www.ebay.co.uk/itm/100W-Watt-Semi-Flexible-Solar-Panel-For-12V-Battery-Charging-Boats-Caravans-RV-/380658742405?pt=UK_Gadgets&hash=item58a1077485#ht_5069wt_932

[Justme]

I dont think they are the sort that you can glue down & walk on.

 

Might be worth checking.

[Ex- Member]

Well they are a lot cheaper than the the other flexible I think you're talking about. That type are ones that adhere to the surface and can be walked on. There's mention of fixing by bonding with the ebay panels but walking on them doesn't look a good option, and there's no mention of being able to. I also note they only output 5 amps.

 

I';; keep my eye on these though, I might need to add extra panels for winter, wold be good to get them bigger though 250 watt each.

Edited August 31, 2013 by Julynian

[junior]

I dont think they are the sort that you can glue down & walk on.

 

Might be worth checking.

 

I'm not fussed about walking on them, i'll have enough room to walk round them. I hadn't thought about how they are to be fixed, although i hadn't planned to glue them.

I also note they only output 5 amps.

 

 

I hadnt noticed that, but then again i don't really know my amps from my watts from my volts, it's all japanese to me. I just knew i wanted 100w panels (X2).

 

What sort of amp output SHOULD i be looking for/expecting?

[Phil Ambrose]

To work out amps divide watts by voltage so in the case of a 100w panel the very best you can get is about 8amps. This figure would be the best you could get mid summer with the panels at the right inclination to the sun.

Phil

[MtB]

I can't see how they can possibly be 100W panels if the max current they can supply is 5.3 amps.

 

Amps x voltage = watts. 5.3 amps x 12 volts = 67 Watts.

 

 

MtB

[grahame r]

I can't see how they can possibly be 100W panels if the max current they can supply is 5.3 amps.

 

Amps x voltage = watts. 5.3 amps x 12 volts = 67 Watts.

 

 

MtB

They're 18.9v x 5.3amps = 100w. It says for 12v application

[MtB]

Spec on the listing states "

Current at maximum power (Imp)

Av 5.3A @ 12v

 

MtB

[Phil Ambrose]

You are not going to get 18.9 volts into your battery though.

 

Phil

[blackrose]

 

I'm not fussed about walking on them, i'll have enough room to walk round them. I hadn't thought about how they are to be fixed, although i hadn't planned to glue them.

 

The second link you posted says they can be bonded to the roof "This 100W flexible solar panel at 2.8kg is extremely light but very durable. It can be bonded directly or screwed/bolted to the roof using the pre-drilled holes in the corners of the panel."

 

It would certainly make them look a bit better than the way some panel installations ruin the look of the boat, but it won't be the most effective way of mounting them in terms of producing amps. Although you may not be able to walk on them, it migh be worth checking how durable they are if something gets dropped on them for example.

 

I can't really comment on the electrical side as I have no experience with solar panels, but I'd be interested to know if the controllers that come with the panels are any good or whether you should use another type of controller.

[Jigsawged]

During my extended cruising this season, I have met a good number of narrow boaters who have either installed or had installed, solar panels and without exception, they have all reported positively on them (well they would say that - wouldn't they?) I know nothing about them other than what I read on the forum but it does make me wonder.

 

A chap I met yesterday had three small panels (measuring about 3ft x 2ft) which had been installed by a specialist in under 3 hours. He maintained that he could sit for 4 days without running the engine except for hot water and that he was running a variety of 240 items without any difficulty.

 

The jury is still out but if they are a worthwhile investment, the truth will be known on this forum before long.

[Ex- Member]

 

The second link you posted says they can be bonded to the roof "This 100W flexible solar panel at 2.8kg is extremely light but very durable. It can be bonded directly or screwed/bolted to the roof using the pre-drilled holes in the corners of the panel."

 

It would certainly make them look a bit better than the way some panel installations ruin the look of the boat, but it won't be the most effective way of mounting them in terms of producing amps. Although you may not be able to walk on them, it migh be worth checking how durable they are if something gets dropped on them for example.

 

I can't really comment on the electrical side as I have no experience with solar panels, but I'd be interested to know if the controllers that come with the panels are any good or whether you should use another type of controller.

 

There are quite a few semi flexible panels on e-bay, not as cheap as these though although they clearly are not 100amp if they only put out 5.3amps at 12v as MTB has pointed out, so I'm already dubious.

 

Other flexi panels do say they can be walked upon but only with soft sole, so I would assume slippers or deck shoes.

 

The panels do not include a 10 amp controller either, it states you will need one. Possibly a MPPT controller might work better with them unsure.

 

I'm watching some of these though. http://www.ebay.co.uk/itm/100W-flexible-solar-panel-2x50W-semi-flexible-solar-panel-for-RV-boat-camper-/360651749569?pt=UK_Gadgets&hash=item53f884f8c1

 

Our array is big and there's no way Lynn will have more panels like that, these though I could easily fit another 3/4 which would use our Outback up to it's maximum amps output. They wouldn't intrude in to the roof walkways either side either, so no need to walk on them anyway. They need to fall in price first though so I'll give it a couple of months and get some feedback on the cheaper ones.

[junior]

During my extended cruising this season, I have met a good number of narrow boaters who have either installed or had installed, solar panels and without exception, they have all reported positively on them (well they would say that - wouldn't they?) I know nothing about them other than what I read on the forum but it does make me wonder.

 

A chap I met yesterday had three small panels (measuring about 3ft x 2ft) which had been installed by a specialist in under 3 hours. He maintained that he could sit for 4 days without running the engine except for hot water and that he was running a variety of 240 items without any difficulty.

 

The jury is still out but if they are a worthwhile investment, the truth will be known on this forum before long.

 

My panels will not be for powering things whilst i am on the boat. They will be to ensure that when i leave the boat for a week to go to work i will returned to a fully charged battery bank. The system that i am having installed will do just that, of that i am confident. I will of course get the added benefit in the summer of them being able to provide a certain ammount of my daily elecrical useage as well.

 

As i will be sourcing the panels for the system (and i know nothing about electrics), i though i would get opinions on the panels i had found BEFORE i commit to buying them. Someone has already pointed out that the amps provided by these panels might be too low, so i am going to compare that figure to the alternative more expensive ones.

 

There are quite a few semi flexible panels on e-bay, not as cheap as these though although they clearly are not 100amp if they only put out 5.3amps at 12v as MTB has pointed out, so I'm already dubious.

 

Other flexi panels do say they can be walked upon but only with soft sole, so I would assume slippers or deck shoes.

 

The panels do not include a 10 amp controller either, it states you will need one. Possibly a MPPT controller might work better with them unsure.

 

I'm watching some of these though. http://www.ebay.co.uk/itm/100W-flexible-solar-panel-2x50W-semi-flexible-solar-panel-for-RV-boat-camper-/360651749569?pt=UK_Gadgets&hash=item53f884f8c1

 

 

 

 

I'm not fussed about what controllers they do/do not come with, i'm purchasing a seperate MPPT 30amp.

 

I've looked at those panels you provide the link to. Being a technaphobe i can't see what amps they put out so as to be able to compare them to the cheaper ones i linked to in my OP.

 

I have about £300 to spend on panels and had hoped to get 200w for my dosh. I wondered if i was to buy THREE of the panels in your link (150w total) for about £300 ish, i may end up getting MORE power out of them than if i was to but TWO of the panels in my OP (200w advertised but MTB thinks otherwise) for about £300 ish. Whaddya think?

 

 

Edited September 1, 2013 by junior

[Ex- Member]

 

My panels will not be for powering things whilst i am on the boat. They will be to ensure that when i leave the boat for a week to go to work i will returned to a fully charged battery bank. The system that i am having installed will do just that, of that i am confident. I will of course get the added benefit in the summer of them being able to provide a certain ammount of my daily elecrical useage as well.

 

As i will be sourcing the panels for the system (and i know nothing about electrics), i though i would get opinions on the panels i had found BEFORE i commit to buying them. Someone has already pointed out that the amps provided by these panels might be too low, so i am going to compare that figure to the alternative more expensive ones.

 

The amperage of the panel is irrelevant in respect of the amperage you require. Having looked again it could be to do with the open circuit voltage being 19v I', no expert so will await comment from those who understand LOL

 

What you need to assess is the amount of amps required to maintain you batteries whilst you're away. So you need to assess total amps of battery bank, the SOC of that bank when you leave for work and take account of any power usage whilst away. It will be difficult though because as winter approaches less and less solar energy becomes available. You'll probably need 3 times the panels in winter to produce the same as one through the summer, so need to find a balance or go for fully charged batteries through the winter and lots of excess energy in summer, you can always decommission panels though when not required.

[junior]

 

 

What you need to assess is the amount of amps required to maintain you batteries whilst you're away. So you need to assess total amps of battery bank, the SOC of that bank when you leave for work and take account of any power usage whilst away. It will be difficult though because as winter approaches less and less solar energy becomes available. You'll probably need 3 times the panels in winter to produce the same as one through the summer, so need to find a balance or go for fully charged batteries through the winter and lots of excess energy in summer, you can always decommission panels though when not required.

 

Unfortunately i am being guided by funds though. It's a simple case of getting as much solar output (into my batteries) as i can for my £300. Well i say simple, it's not really as i have limited space on the roof so can't just get those whopping great fixed 100w/200w panels. I have a narrow roof and lots of un-moveable fittings. I also don't want to change the asthetic profile of the boat too much if i can help it, hence the flexible flat ones.

 

There will be no electrical useage on the boat while i am away as far as i know and the battery isolator will be off if i can do that and still charge them from solar.

 

If i get no better suggestions during the day or unless someone see's this and tells me i am wasting my money, i will probably order 2 of the ones in my OP.

[Paul C]

You're wasting your money ordering 2 of them, if you only need 1 of them! If its really just for preserving the batteries, then 1A or less should do this with good condition ones.

 

But I'd recommend you look a little beyond just keeping the batteries charged while unattended. For example, our boat has 200W of solar panels, and they allow the fridge/freezer to be left on through the summertime and occasional use of electrical items such as microwave, laptop, radio, TV, etc.

[junior]

You're wasting your money ordering 2 of them, if you only need 1 of them! If its really just for preserving the batteries, then 1A or less should do this with good condition ones.

 

But I'd recommend you look a little beyond just keeping the batteries charged while unattended. For example, our boat has 200W of solar panels, and they allow the fridge/freezer to be left on through the summertime and occasional use of electrical items such as microwave, laptop, radio, TV, etc.

 

Hence why i am going to order two of them Or have i misunderstood you?

[trackman]

Solar panels don't produce a fixed voltage, it varies with the sun on them. The maximum may be up to 20V or more depending on the type of panel. If several panels are wired in series then much higher voltages can be generated of course.

This is why there is apparently a discrepancy between the quoted 100W and the maximum current stated. I assume that the max current is at a significantly higher voltage than 12V to deliver the 100W at 5.3A.

For this reason you need a controller to put out the correct voltage for your batteries. MPPT controllers do this most effectively, and are even able to put out a higher voltage than the panels are generating in some cases. The power stays the same of course, volts x amps staying constant (ignoring the slight losses inside the controller of course).

[Timleech]

You're wasting your money ordering 2 of them, if you only need 1 of them! If its really just for preserving the batteries, then 1A or less should do this with good condition ones.

c.

 

If I've understood the OP, his need is similar to ours in that he may need to leave the boat with batteries less than fully charged, so they need the charge to be topped up as well as maintained. We have 2 x 80W, similar but not identical, bought from a Chinese ebay supplier 'from UK stock', limited experience so far but they seem to be doing the job.

 

Tim

Edited September 1, 2013 by Timleech

[blackrose]

During my extended cruising this season, I have met a good number of narrow boaters who have either installed or had installed, solar panels and without exception, they have all reported positively on them (well they would say that - wouldn't they?) I know nothing about them other than what I read on the forum but it does make me wonder.

 

A chap I met yesterday had three small panels (measuring about 3ft x 2ft) which had been installed by a specialist in under 3 hours. He maintained that he could sit for 4 days without running the engine except for hot water and that he was running a variety of 240 items without any difficulty.

 

The jury is still out but if they are a worthwhile investment, the truth will be known on this forum before long.

 

I don't think the jury is out at all on solar panels. As others have said, it really depends on one's 12v power consumption and what you want them to do.

 

I have mostly led lights, a gas fridge, 12v car stereo and a mini 12v flatscreen TV that only draw 1 amp each (in addition to mains TV and stereo for shore power use). I also have a gas water heater in addition to my calorifier. I don't have any solar panels but I can also sit for 4 days without running the engine even for hot water - and my batteries are 8 years old!

Edited September 1, 2013 by blackrose

[smileypete]

Might be worth a trawl of Ebay for the 18V RV/camping type panels, should get them for ~80p/watt and some will fit nicely on a NB roof, maybe build a couple into a roof box.

 

cheers, Pete.

~smpt~

[Justme]

If you dont want to walk on them then get standard framed panels for about 50p per watt.