Solar panel purchase ----- which type

[clyst]

Hi all I need to boost my charging system up . Currently apart from the main engine battery charging is by an "Air Breeze" which doesnt really fullfill our needs so going for solar panels too.
What I need now is guidance as to what type is best and where to purchase . I think I need probably an 80 to 100 watt panel or is it best to split ie two 40s or 50s ??

E-bay seems a bit confusing , lots of different types and lots from China .

Thanks

 

[martinriches]

I fitted a cheap Chinese 60 watt panel from eBay last winter.plus a charge controller that splits the charge into two battery's. cost about £130 and so far very pleased with it. It keeps both battery's topped up and I can spend a couple of days on the boat without resorting to the mains charger.

Martin

 

[jordanbasset]

We bought two of these last year -
http://www.ebay.co.uk/itm/100W-Mono...Accessories&hash=item1e6e1453c5#ht_4149wt_905
Very satisfied, even had the slow cooker working the other day, drawing 7.5 amps for 1 hour and 5.5.amps for 5 hours through an inverter, plus all the usual electrical items going. Gave us plenty of power. Time will tell as to their durability but very happy so far.

 

[Ex-SolentBoy]

This is what Rustler Yachts use.

Very good quality and you can walk on them.

http://www.barden-ukshop.com/solara-semi-flexible-solar-panels-52-c.asp

 

[noelex]

The best advice is to fit the maximum watts you can. Alternatively do a careful energy analysis, then fit the maximum watts you can
One 80w panel or 2x40w are very similar in output, it's much more important what fits best. If you have a choice 2x40w will give slightly greater output, but the difference is small.
I have not used the eBay panels, but they get good reports for the price. Going for a name brand, like Kyocera gives something that is a bit more durable, uses more efficient cells so is a bit smaller for the same watts and will meet its specifications. (The eBay panels are usually a bit optimistic). You also get a warranty. The drawback is greater cost.
If you are looking for around 100 w I would go for 12v panels. These will have a Voc of about 22v. You will need a regulator at that size I would use a PWR model that will cope with the maximum current, or larger if you may increase the panels in the future. A regulator with 2 stages ( boost ant float) is better.

 

[BAtoo]

Fit the biggest you can at the price you can afford; if you can afford it then go for "walk-on" ones.
Put them in the least inconvenient place and accept they will be compromised to some extent by shadows from the rigging etc..
Go for ones with an in-built bypass between the cells to reduce shadow effects.
PWR regulator is preferable to have a float stage. At the least get an on-off regulator for when the battery is full.
My e-bay 20w special fitted last year has kept my 140AH battery fine over the winter; fully charged with 13.4V yesterday. Fitted horizontally at the front of the hatchway.

 

[VicS]

Hi all I need to boost my charging system up . Currently apart from the main engine battery charging is by an "Air Breeze" which doesnt really fullfill our needs so going for solar panels too.
What I need now is guidance as to what type is best and where to purchase . I think I need probably an 80 to 100 watt panel or is it best to split ie two 40s or 50s ??

E-bay seems a bit confusing , lots of different types and lots from China .

Thanks

Two samll panels in parallel might enable you to fit a larger total wattage if you dont have a large area in which to fit a single large panel

Three basic types.

Monocrystalline. Said to be the most effeicient but most expensive. Not flexible and has the be mounted in a rigid frame

Polycrystalline. Not quite as effeicient or expensive. Can be made into slightly flexible panels.

Amorphous. Least efficient, least expensive. Can be made into very thin flexible panels.

Other factors involved as well such as bypass diodes.

Choice of regulator equally important and possibly more confusing.

Basic types that simply disconnect at a certain volatge and reconnect again at another lower voltage

Pulse width modulated (PWM) which actually control the charge rate as the battery becomes charged

Maximum Power Point Tracking (MPPT) which controls the panel at its maximum output power, which may be at around 16 volts, and convert the the power to the correct volts for battery charging by electronic jiggery-pokery .

If you buy cheap tat from ebay be sure you get panels intended for battery charging, not panels with an open circuit volts of only 12 volts
Check also if a blocking diode is fitted or if you will have to fit one

 

[lumphammer]

Using a number of smaller panels might be more efficient if there is a likelyhood that part may be affected by shading. As all the cells in a single panel are in series any shading will affect the total power output.
By running two or three panels in parallel only the shaded panel will be affected the others should still be outputing full power.

 

[Iain C]

Picking up on this thread, can anyone point me in the direction of some smallish semi flexible ones...chinese eBay should be fine.

I want to mount them on my sprayhood (if I'm honest it gets folded away about twice a year...), on the top panel, one either side of the boom to hopefully reduce any shadow issues.

A recommendation would be good too! Thanks!

 

[GrahamM376]

We have had 4 x 43W Kyoceras on gantry + an LVM 25W semi flexible on aft coachroof for several years. All work well but can't compare to other makes as haven't used others.

Best place to mount them is on a stern gantry with ability to tilt fore and aft. It's surprising how a little shade will greatly reduce output - and don't believe the makers claims, particularly in UK sun.

 

[clyst]

Thanks fort all your replies chaps . Lot of advice but it seems that you dont get many amps for your dosh !! Back to the drawing board unless someone can come up with a unit that knocks out 7 to 8 amps in our british weather.

Cheers

 

[AntarcticPilot]

Thanks fort all your replies chaps . Lot of advice but it seems that you dont get many amps for your dosh !! Back to the drawing board unless someone can come up with a unit that knocks out 7 to 8 amps in our british weather.

Cheers

Well, the problem is that Solar Photovoltaic cells have a pretty low efficiency; a few percent. I think the very best are less than 10%, and they are made of material that costs a fortune. You're looking at 100 watt panels to get 7 or 8 amps at 12 volts; I'm just about to have that sort of thing on my roof - that's 10 panels at 220 watts each. So, the panels ARE available - but whether they are suitable for a mobile, unstable mount is another question. And my panels will cost around £500 each, with installation etc. The EXPECTED output - averaged over a year, day and night - is a lot less than half the rated value. It's still a better investment for me than leaving the money invested in a bank.

I have a wind generator - a Rutland 913. I also have an HRDi controller, which allows for an additional input from a solar panel. Some time, when I can figure out a sensible installation, I may add a solar panel - that way I should get the best of both worlds. The Rutland only gives a big output when the weather is likely to be cloudy; the solar panel will give an output when the Rutland is not performing (they need about 15 knots of wind to work).

 

[pappaecho]

I bought an 80 watt Chinese panel on Ebay last year. I have 600 amp hour storage, and in the dull grey of May they are only at 13.76 volts

 

[VicMallows]

It's still a better investment for me than leaving the money invested in a bank.

Only because the rest of us (with unsuitable E-W roofs ) are subsidising you via the absurd FIT.