Solar panel recommendation again please!

[Iain C]

Ok, I really need to get my solar panels ordered before this "summer's" cruise. Looking at other smaller boats, I've decided the best strategy will be 2 panels, on top of the sprayhood, held in place by bungee and clips, easily demountable for dropping the hood or silly weather. I'm looking for personal recomendations if possible. I'm afraid I havent done any of the "sums" re power, but let's say worse case scenario I could be running:

CP180 plotter
VHF Rx
ST1000 tiller pilot
NASA clipper duet
NASA AIS Radar
NASA GPS repeater
Tack Tick Wind (12v, not solar)
A phone or ipad on charge
12v camping style coolbox
Tricolour
BM1 battery monitor
Base model Pilot gas sniffer
Occasional Sony car stereo use

The above scenario would be very rare TBH (unlikely to have the stereo on at night) and the longest single passage realistically I will be doing will be cross channel. I understand the draw from the NASA instruments and sniffer will be very minimal. No water pumps, showers, TVs or electric windlasses on board. I am in the process of swapping out cabin lighting for LEDs and will change the tric too next time I am up that way!

Am I right in saying 2 panels are better than one at the lower end, as they are less susceptible to shadows? I have a voltage regulator, can I wire both panels to one?

The panels need to be reasonable value, not looking for ocean spec here, semi flexible, fairly tough, and with eyelets or similar for rope/bungee mounting. Area approx 2'x1 each.

Any recommendations chaps?

 

[TQA]

Forget running the cool box on 4'x1' of fixed solar.

I have 15 sq ft 400 watts of tiltable solar and 675 amp/hrs battery capacity and am in the Caribbean. That runs an efficient compressor fridge and all other domestic stuff.

I like Kyocera panels and they have a good rep in the cruising community out here.

 

[oldvarnish]

Do the sums, and then buy Kyocera.

 

[VicS]

As Old Varnish says, "do the sums first". Work out what your daily power consumption will be in Amp hours from the current each item will draw and the number of hours it will be in use.

Size your battery to ensure that you do not run it below half charge.

Work out how much solar panel capacity will be needed to make up for the power used in the length of time your will have your panels deployed Take the manufacturers figures for the current output. ( The power quoted is the power at some optimum terminal volts , which should be quoted but is usually around 17 volts. Dividing the nominal power by 12 will give an unrealistic figure for the current output.

Decide what sort of regulator you want to use. The simple ones merely disconnect the panel when the battery volts reach some predetermined figure to prevent overcharging.
Better ones are "Pulse width modulated" (PWM) and control the rate of charge.
To extract the maximum power from the panels "Maximum power point tracking" ( MPPT) regulators control the panel at the optimum terminal volts and convert the extra volts into extra current at battery volts by electronic jiggery-pokery.

Panels can be simply connected in parallel but unless they are fitted with diodes already they will need blocking diodes


I'd recommend permanently mounted solar panels so that they are always operational when there is light to convert into electricity. A flexible panel stowed away in locker is serving no useful purpose.

 

[davidej]

A 2ft by 1ft panel is unlikely to be more than 40 watts.

We have similar and it is great for recharging over a week what you have taken out in a days sailing - we are on a swinging mooring so no plugging to the mains

However don't expect it to keep up with continuous use of all that gear on your annual cruise - you would need 10 times as much or go into a marina each night and plug in.

 

[Pete7]

Iain, is price an issue? The reason I ask is we have one of the Solar 45w semi flexible panels from Barden batteries. It's okay (and dammed expensive) but only give about 1.5 AH at best mounted infront of the sprayhood, so subject to some shading depending on the boom.

However, we also have an e bay 80w square rigid panel mounted on the pushpit which cost £108 and really does give a good charge of over 4AH.

There is no comparison the rigid panel is much better value. We have a similar use to you including fridge and laptop etc. I am not looking to be completely self suficient in solar power, but enough that we can do a week in harbour without running the engines or lowering the batteries to far. I think the two panels together will do that for us.

Pete

 

[vyv_cox]

The cool box is probably the killer. Could be drawing 5 amps or more. You are going to need something like 200 watts of solar and maybe 350 Ah of battery to run that 24 hours per day. Small flexible panels in UK are just not going to deliver.

Agree on Kyocera. We have 125 watts in two panels, runs the fridge well in high summer but struggles in autumn, in Greece. Our fridge takes about 3 amps and is on around 30% of the time.

 

[Iain C]

Ok, thanks all. I think a rethink is needed then. As you've probably worked out, I'm an electrical Luddite...perhaps I will have a look at the collbox and see if the draw is marked on it somewhere.

I don't have a big enough boat for acres of panels, so perhaps I need to be more realistic and whilst still aiming for a similar sized setup, have more realistic expectations of what it can do.

TBH, for the bulk of the "weekend sailing" year, if I could come down to a full battery thanks to the solar panels, and have enough oomph combined with the inevitable hour or so of motoring for me to run the coolbox to Sunday lunchtime, that's a big step forward.

What are people's experiences with the cheaper eBay panels? Any good?

Also, the coolbox is amazingly efficient for a cheapie...over the jubilee weekend stuff was still very cold by Tuesday lunchtime, without the fan running at all...

 

[pappaecho]

With regard to the coolbox or fridge, what is the acceptable temperature for the food and beer etc?
If the fridge or cool box is properly insulated, you can get away with not running it at night. That means the solar panels more less runs it during the day, and it does not deplete the house batteries at night

 

[TQA]

If you are mostly weekending with limited charging capacity, I have two words for you ;-

BUY ICE!

 

[BAtoo]

Ok,

CP180 plotter
VHF Rx
ST1000 tiller pilot
NASA clipper duet
NASA AIS Radar
NASA GPS repeater
Tack Tick Wind (12v, not solar)
A phone or ipad on charge
12v camping style coolbox
Tricolour
BM1 battery monitor
Base model Pilot gas sniffer
Occasional Sony car stereo use

Look at it another way:

Whats the biggest you can fit?

Whats the best you can afford?

Then buy the biggest and best (that you can fit/afford)


........then live within you means......



This is the non-euro approach to solar panels


(& buy ICE.)

 

[BAtoo]

Alternatively:

CP180 plotter - chart & pencil
VHF Rx - be self rel0ant
ST1000 tiller pilot - steer it yourself
NASA clipper duet - maybe...
NASA AIS Radar - No1 eyeball
NASA GPS repeater - take the chart & pencil into the cockpit/have a second chart
Tack Tick Wind (12v, not solar) - by tacTic Solar
A phone or ipad on charge - FFS you are on holiday..
12v camping style coolbox - buy ice
Tricolour - buy ice/drink warm beer - you are English aren't you??
BM1 battery monitor - if you don't use it you won't need to count it...
Base model Pilot gas sniffer - turn the gas off
Occasional Sony car stereo use - sing (or i-pod)



This is the "greek-now-we-voted-to-stay-in-the-euro" austerity guide to sailing......

 

[Mistroma]

I'd agree about efficiency (i.e. Cut out stuff you don't need). However, that doesn't mean doing without.

Radar: Turn it off (plotters often put it in Standby by default). Mostly used in poor vis. and Nav. lights on at same time so solar not particularly relevant (not much sun and large load).

Cool box: Terribly inefficient if Peltier effect type. Well insulated compressor driven unit much better. Or use ice if installation cost is an issue (if you can get block ice).

Anchor light: LED

etc.

Rigid panels give most bang per buck. I considered "marine" flexibles but decided to try a 65W BP panel from e-Bay. Excess stock from solar installation company (approx. £100). It was genuine, brand new and works well.

However, it is hugely affected by shadowing and only mounting place I have is on coach roof. I accepted that as cost was low.

DATA FROM 20th May - 18th June: 720 hours

65W Panel: 483 Ahr (Avg. 16 Ahr each day)
Rutland 913: 248 Ahr (Avg. 8 Ahr each day)
Total: 731Ahr

This covers Eire - South Brittany. Wind gen. tied up a couple of times when holed up in a marina. Solar panel just tied down on deck (no attempt to optimise location, move out of shade etc.).

I imagine that you will get similar performance from a cheap e-Bay unit (16-18 Ahr each day). No idea how they compare to my BP unit (could well be same quality for all I know).

You are correct to consider a solar panel (much better buy than wind-gen. but both are useful). Don't expect to cover all power requirements as it is difficult to find enough space (unless you add a gantry on the stern).

 

[William_H]

Solar power

As said throw away the peltier style cool box and use ice. Or buy a compressor type freezer.
Measure up the area you have for panels and buy to fit. 2 panels are fine in parallel. If they end up being small and you only use them when on board don't use a regulator. But if they are a 20 w or more then don't leave them on when you are away from the boat for the week. (Or fit regulator)
Monitor your current usage and turn things off as necessary to maintain batteries 50%. good luck olewill

 

[jordanbasset]

What are people's experiences with the cheaper eBay panels? Any good?

Bought two 100w rigid panels from e-bay last year, very pleased with them. Keeps my 4 x 140 amp batteries topped up. Been tied up now for 4 days (meltemi in the Agean) and even with the slow cooker (through an invertor) being used for several hours in the day, fridge, computers (two) t.v. etc never been close to going below 80% even at 6am in the morning. Back to full capacity by 11am. Looking at other more expensive panels they seem very similar in build quality and look to my untrained eyes as my own panels.
This is the company I bought from
http://www.ebay.co.uk/itm/100W-Mono...ervan_Caravan_Accessories&hash=item1e63fed57c
No connection only satisfied customer etc

 

[ukmctc]

Look at it another way:

Whats the biggest you can fit?

Whats the best you can afford?

Then buy the biggest and best (that you can fit/afford)


........then live within you means......



This is the non-euro approach to solar panels


(& buy ICE.)

+1
thats the best way togo, I have 3 x BP solar panels 2 x 80 and 1x 65 the biggest drain will be your coolbox, it will use all the power supplied by your panels so think permenant mount large panels, forget cool box.

 

[RupertW]

If you are mostly weekending with limited charging capacity, I have two words for you ;-

BUY ICE!

No, buy this http:www.amazon.co.uk/Andrew-James-Compact-Counter-Machine/dp/B002ALJAVM

Unless your coolbox is already a fast cooling compressor type this will really accelerate the cooling of your food and provide bags of ice for drinks ready whenever you are in a Marina. We find ice often runs out just when you need it and this is the business.

Often some of the ice is still frozen a week after leaving a marina as the coolbox just keeps the temp steady without having to work too hard or too often.

 

[Iain C]

Thanks Rupert but my boat is on a swinging mooring and I try to avoid marinas where possible...more of a town quay/trots/anchor/visitors mooring kinda guy. And if I was in a marina I'd probably just run the coolbox off 240v or plug my battery charger in. Nice bit of kit though, G&Ts without ice or sliced lime is a just plain wrong!

OK so I think it's going to be a case of measure the available space, buy the biggest panels I can without breaking the bank and take it from there...perhaps on a smaller boat with limited space for panels I should be looking at a second alternator or some clever charging in the engine department, and just rely on the panels to keep the battery topped up when not in use.

I did have some suitable space for hard panels but after having converted to coach roof winching (much more important!) that's not an option now as there's string everywhere!

 

[TQA]

I did have some suitable space for hard panels but after having converted to coach roof winching (much more important!) that's not an option now as there's string everywhere!

I have seen some boats with a set up that hinges the panels on the top lifeline and props them up with sticks when at anchor and securing them to the lower lifeline on passage.

This would not be my choice but is a low tech low cost solution that seems to work.

 

[AngusMcDoon]

I have a Spectraflex 32W solar panel. This is amorphous so doesn't suffer much if there is a small shadow falling on it. I get 1A on a cloudy bright day and 2A in bright sun at the best angle in the UK. My only other source of power when away is 6A maximum from my outboard engine, all into 120Ah of batteries.

I run...

Tillerpilot nearly all the time when sailing
Waeco 18l compressor coolbox continuously (500mA on average in UK summer)
Full set of ST60 instruments
Chartplotter now and then
LED navigation and internal lights
VHF now and then, similarly entertainment radio
Phone chargers
Navtex
AIS receiver when needed
Recharge a netbook every few days

Despite the doom and gloom mongers and their humongous battery banks, generators and huge solar panel arrays, I have never run out of power yet.