Solar panel question

AntarcticPilot

AntarcticPilot

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www.cooperandyau.co.uk
Has anyone used these: https://www.ebay.co.uk//itm/132337008784 ?

They look like a good deal at a reasonable price - and there's the potential for improving on the price by buying when I'm in Hong Kong in January! But are they any good? I'm looking for a cabin top mount with two panels - the more the merrier, but I'll be limited by price. The panels must a) be slightly flexible to take up the curve of the cabin top and b) be OK for walking on - they'll be located near the mast, so in an area that takes some foot traffic.

Comments?
 
I've no idea whether it matters but those 100W panels are 3 x 11 so 33 cells and rather elongated. Mine 100W semi-flexibles are 4 x 9 so 36 cells. Whether the shape is a problem depends on the space you have but I think that the fewer cells is resulting in a reduced maximum voltage under load of only 16.5V. This could be important with an MPPT controller but I'm sure the controller supplied is PWM so perhaps not so important?

However, my panels were £200 each and no controller so you're clearly getting a lot more bang for your buck. ;)

Richard
 
RichardS said:
I've no idea whether it matters but those 100W panels are 3 x 11 so 33 cells and rather elongated. Mine 100W semi-flexibles are 4 x 9 so 36 cells. Whether the shape is a problem depends on the space you have but I think that the fewer cells is resulting in a reduced maximum voltage under load of only 16.5V. This could be important with an MPPT controller but I'm sure the controller supplied is PWM so perhaps not so important?

However, my panels were £200 each and no controller so you're clearly getting a lot more bang for your buck. ;)

Richard
Click to expand...
The space is such that a long, thin shape will fit better than a squarer one. I'm thinking of one either side of the mast, extending forward next to the forehatch. There's convenient access for wiring in that location, and at least one panel ought to be catching the sun at any given time!
 
AntarcticPilot said:
The space is such that a long, thin shape will fit better than a squarer one.
Click to expand...

Is that on deck or in the case on the way back from HK?

Beware that I've been stopped by customs coming back from HK or Singapore when they've been on the hunt for electronic goods (but for some reason never when coming back from dodgy South American drug-producing countries). I even got chased once - I was unaware of it but I've got long legs and the poor woman chasing me had short ones so the effect was the same. She apparently thought I was smuggling a laptop in and was really disappointed when she saw my ancient company-allocated one.
 
lpdsn said:
Is that on deck or in the case on the way back from HK?

Beware that I've been stopped by customs coming back from HK or Singapore when they've been on the hunt for electronic goods (but for some reason never when coming back from dodgy South American drug-producing countries). I even got chased once - I was unaware of it but I've got long legs and the poor woman chasing me had short ones so the effect was the same. She apparently thought I was smuggling a laptop in and was really disappointed when she saw my ancient company-allocated one.
Click to expand...
I doubt they'd fit in checked baggage- and I don't sail to Hong Kong. I've no doubt that we could, but it would take a while, and my wife only has about 5 weeks leave a year! If I bought them in HK, I'd probably arrange for them to be shipped.

There's not usually much point in buying PCs or laptops in HK - the prices are actually a little higher than in the UK, for branded goods with some sort of warranty! Low cost consumer electronics are different - bluetooth accessories and such like are considerably cheaper, but at a price point that won't attract attention from HMRC!

The reason I might buy in HK is because my wife has contacts in the green energy area in HK, and they may be able to point at sources that are cheap enough to get in below the personal allowance. As she is from HK, we visit there at least once a year.
 
I know that particular controller is rubbish (after having tried 4 of them from different outlets), but does that mean the solar panels are not top notch? I don't know I'm afraid.
 
Not sure if they are any good or not, never used them, but their output figures are erm... optimistic :)

IMO, solar installations are a long term investment, don't skimp.
 
Oooh - what was wrong with the controller. I reckon my huge 2A regulator on my trickle charge panel is on the way out and I was just thinking that controlled (which costs about £6) would do me just fine...
 
I must agree with earlier comments about the controller. I bought one on e bay, about £15 I think, and it was useless and went in the bin. I had bought a 10w solar panel from NASA to keep a Numax 75 Amp hour battery topped up and it seems to be working fine without a controller.
 
ShinyShoe said:
Oooh - what was wrong with the controller. I reckon my huge 2A regulator on my trickle charge panel is on the way out and I was just thinking that controlled (which costs about £6) would do me just fine...
Click to expand...

It may work for you depending upon your battery.
What it DOES do is allow a large solar panel to input 14.4 Volts and no more (so that is good).

What it does not do (although various adverts state it should) is allow one to change the voltage from 14.4 to a lower voltage.
In fact is does not do any other advertised things.

It simply controls the 20V solar panel to input 14.4 volts. This means the battery could overcharge (gas and lose electrolyte and therefore need topping up - if one does not have a sealed battery) on clear, long sunny days.

It is supposed to have the option of going to float charge, but the ones I have bought have not done that.
 
Don't think much of the ebay supplier, they can't even get the title and the details correct.

As Paul said it might be worth going for a better quality panel perhaps EFTE like this, just not sure they can be walked on.

http://www.ebay.co.uk/itm/100W-50W-...d=162770809320&_trksid=p2047675.c100005.m2219

I have bought from Photo-Universe before without problem.

However, sometimes there are problem with solar you don't foresee

user27361_pic28035_1506082202.jpg
 
Last edited:
Pete7 said:
Don't think much of the ebay supplier, they can't even get the title and the details correct.

As Paul said it might be worth going for a better quality panel perhaps EFTE like this, just not sure they can be walked on.

http://www.ebay.co.uk/itm/100W-50W-...d=162770809320&_trksid=p2047675.c100005.m2219

I have bought from Photo-Universe before without problem.

However, sometimes there are problem with solar you don't foresee

View attachment 67573
Click to expand...

Well, our dog is much smaller - but I gather that if you block one cell, it blocks the whole panel...
 
Thanks for all the inputs - I was considering I might need a different controller anyway, as I have two 110 Ah batteries, and would rather charge them separately. I also have a 10w panel that barely keeps up with the self-discharge; all I get from that is that the batteries don't get flat when I leave her. But it won't top the batteries up and keep them in good condition.
 
brainstorm said:
I must agree with earlier comments about the controller. I bought one on e bay, about £15 I think, and it was useless and went in the bin. I had bought a 10w solar panel from NASA to keep a Numax 75 Amp hour battery topped up and it seems to be working fine without a controller.
Click to expand...

I bought a controller for low price and looks similar. Was claimed to be suitable for 24v system with auto selection. Not so it will only suit a 12v battery. Apparently OK for 12v system. olewill
 
Apols to atlanticPilot for the thread hijack.
Sailingsaves said:
It is supposed to have the option of going to float charge, but the ones I have bought have not done that.
Click to expand...
Argh! Thats what I was hoping for. My panel isn't huge 20W or 30W on 120Ah, so I may not really need anything. But I do wonder what happens if we get a long windless summer one year so it charges the battery well and at the same time I don't do much sailing and so never go near and run down any electrics.

I've had the odd situation where the battery has run low while I've been there. Left it with the solar going for 2 weeks in decent summer days. Even if I only got say 5W of power for 5 hours (25W = 2A @12V) - I should have topped the battery up by 28Ah yet I was still registering empty. (Definitely no electrics on). Of course that was the weekend the multimeter battery died too! (I would actually expect in summer to get a complete top up in the two weeks (10hrs at maybe 7.5W = ~6A/day = 84Ah) unless I'm being over optomistic in my battery requirements.

Battery charged fine from engine and took home and charged on fancy charger and been fine since. Was just thinking by current little regulator isn't up to the job!
 
ShinyShoe said:
Apols to atlanticPilot for the thread hijack.

Argh! Thats what I was hoping for. My panel isn't huge 20W or 30W on 120Ah, so I may not really need anything. But I do wonder what happens if we get a long windless summer one year so it charges the battery well and at the same time I don't do much sailing and so never go near and run down any electrics.

I've had the odd situation where the battery has run low while I've been there. Left it with the solar going for 2 weeks in decent summer days. Even if I only got say 5W of power for 5 hours (25W = 2A @12V) - I should have topped the battery up by 28Ah yet I was still registering empty. (Definitely no electrics on). Of course that was the weekend the multimeter battery died too! (I would actually expect in summer to get a complete top up in the two weeks (10hrs at maybe 7.5W = ~6A/day = 84Ah) unless I'm being over optomistic in my battery requirements.

Battery charged fine from engine and took home and charged on fancy charger and been fine since. Was just thinking by current little regulator isn't up to the job!
Click to expand...


At 20w or 30w you really ought to have a controller.
 
AntarcticPilot said:
No longer - moved down to Essex last year. Being an 8 hour drive from her turned out to be too much in the end, especially as my wife has less flexibility in her working hours than I did when I was working.
Click to expand...

In that case you probably do need to worry about long sunny days. As SailingSaves says you'd have to check whether a cheap controller would back off from 14.4V when the batteries are charged. In Scotland nature has a way of protecting you from overcharging your batteries with a solar panel. Certainly works in NI, as although I occasionally get gassing on the odd summer day (they're odd because it doesn't rain) water levels don't seem to drop rapidly and a top up every 6 to 9 months is adequate.
 
RichardS said:
I've no idea whether it matters but those 100W panels are 3 x 11 so 33 cells and rather elongated. Mine 100W semi-flexibles are 4 x 9 so 36 cells. Whether the shape is a problem depends on the space you have but I think that the fewer cells is resulting in a reduced maximum voltage under load of only 16.5V. This could be important with an MPPT controller but I'm sure the controller supplied is PWM so perhaps not so important?

However, my panels were £200 each and no controller so you're clearly getting a lot more bang for your buck. ;)

Richard
Click to expand...

Sailingsaves said:
It may work for you depending upon your battery.
What it DOES do is allow a large solar panel to input 14.4 Volts and no more (so that is good).

What it does not do (although various adverts state it should) is allow one to change the voltage from 14.4 to a lower voltage.
In fact is does not do any other advertised things.

It simply controls the 20V solar panel to input 14.4 volts. This means the battery could overcharge (gas and lose electrolyte and therefore need topping up - if one does not have a sealed battery) on clear, long sunny days.

It is supposed to have the option of going to float charge, but the ones I have bought have not done that.
Click to expand...

The user manual is here: http://thytronic.dk/index.php?controller=attachment&id_attachment=81

It confirms Richards thoughts that it is a PWM controller, with 4 stage charging.

It shows how to adjust for flooded, AGM or gel batteries , how to adjust the float voltage and how to set the load disconnect/reconnect parameters.

In view of the doubts it would probably worth, with 200watts worth of solar panel, binning it and investing in a decent MPPT controller.
 
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