What wattage of solar panels should you try for as a liveaboard.

I am looking forward to sunnier climes but have read elsewhere that 600 to 1000 watts is needed with fridge freezer and all the other mod cons. I opted for 640 watts with an mppt controller on a stern arch. With some conservatism on power it just about copes week on week in the uk in the summer but 1,000 watts is probably whats needed year round. I can fit one more panel and reckon that should give total independance anywhere between the med south.
 
OR4751 said:
No - there isn't.
We have 4x100W rigid solar panels bought on a caravaning website.
For the price of less than a single 100W 'marine' solar panel.
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Couldn't agree more, as Nostro well knows we have 2 rigid domestic panels which provide all the power we could possibly need except for running the washing machine. Cost £180 each, 3 years use so far and going strong :)
 
We have 200w + Aerogen which is fine in summer but now the days are getting shorter and a bit of cloud around, barely sufficient particularly when tide holds us sideways to sun, I would like 300w. Biggest killer is the fridge which draws 7 amps, netbook computer very frugal and usually running all day. All interior lights + anchor light LED. Top up when necessary with Honda genny.
 
We have 4x100w semi flexible, with a MPPT controller, were currently in the Med.
Ok be realistic with 4 panels unless you have a boat without, mast, Radar, and VHF Aries your always going to have at least one with shadow on it, (even a couple of sq inches of shadow will stop a panel working completely) so my 400w is at best 3 x 100w (300w).
In the Med in the summer, The panels provide more than needed middle of the day, (the monitor has shown them producing just over 21 amp middle of the day, (while under load, running the kettle through the inverter)
They just about cope evenings, TV, Fridge, lighting etc.
And are totally dead once it's dark, (it's now getting darker earlier)
At no time will they provide more than 15% of what's required to run the air conditioning through the inverter.
 
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blampied said:
We have 4x100 semi flexible, currently in the Med. They provide more than needed middle of the day, just about cope evenings, dead at night, and at no time will they provide more than 10% of what's required to run the air conditioning through the inverter.
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I had 140w of semi flexible which were on top of the saloon roof. The panels developed blisters and after only 2.5 years use will only work briefly in the morning and just before sunset. The company who made them (GB Sol were totally unhelpful and would not answer any of my questions about them or give technical support). I would never buy semi flexibles again even though they did offer to replace them at cost price plus VAT plus transport.
 
Calculate what your average power consumption is every 24 hours.

Work on 9 hours of uninterrupted sunshine in summer, 4 in winter so divide the 24 hour consumption by 9 for summer or 4 for winter.

Convert to watt / hours

Add 20% for losses

Add 30% for the ability to charge, not just maintain.

now you know what would keep you completely independant.

Look into your wallet and decide how independant you want to be!

A generator can charge batteries but it can also make toast in a proper toaster, run a microwave or even a hairdryer. ( Mucho brownie points )

:)
 
Nostrodamus said:
I had 140w of semi flexible which were on top of the saloon roof. The panels developed blisters and after only 2.5 years use will only work briefly in the morning and just before sunset. The company who made them (GB Sol were totally unhelpful and would not answer any of my questions about them or give technical support). I would never buy semi flexibles again even though they did offer to replace them at cost price plus VAT plus transport.
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Hi Nostrodamus.
Can't vouch for the longevity of the semi flexible panels,
Only purchased them via e.bay direct from China last year, about £180 each,
they are still working fine so far, and I'm happy with them.
We only have a 33' motor boat, and the solid ones would have been too heavy / unsightly.
They provide far more than needed during the day, so wouldn't add more panels even if I had the room,
a bigger battery bank (we only have 360 ah bank) would be more usefull to store the excess of the day for the evening.

Any suggestions for what to do with the boat over the winter?
We could stay with the boat but would prefer to return home to Jersey for the deepest part of winter.
We came through the French canals taking 4 months to reach the Med,
Came out at Port st Louis two weeks ago, been as far as Cassis and currently in Marseille!

Port st Louis is a possibility, cost about £1700 to lift out and back in.
Port Nepolian the same, but about £2000
Not sure I want it lifted out in this area due to many stories about the winter Mistral getting to 20c below, causing freezing problems for boats not kept in the water.

Best regards
Paul
 
nimbusgb said:
Calculate what your average power consumption is every 24 hours.

Work on 9 hours of uninterrupted sunshine in summer, 4 in winter so divide the 24 hour consumption by 9 for summer or 4 for winter.

Convert to watt / hours

Add 20% for losses

Add 30% for the ability to charge, not just maintain.

now you know what would keep you completely independant.

Look into your wallet and decide how independant you want to be!

A generator can charge batteries but it can also make toast in a proper toaster, run a microwave or even a hairdryer. ( Mucho brownie points )

:)
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We do all of your last list from our 2000w inverter!
 
RobbieW said:
Short answer - as much as you can fit.

Longer answer - do you first know roughly what your daily usage is in amps ? Good, now you have a target to meet and can work out whether its feasible to meet it with the real estate you have available. If you cant meet it you can either run a regime where you start to minimise use or work out how to make up the shortfall.

Got to go, I'll add a bit more later
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I'd agree with the philosophy - my budgeted 24-hr usage is 50-90 amp-hrs (computer and fridge) and I've a nominal 328 watts of PV panel. May/June/July I can lay at anchor indefinitely without starting the engine, at this time of year system volts gradually drop to about 12.4v by dawn.
The charger never has to bulk-charge during those infrequent times I connect to shore-power.

PS Despite the didactic tone of nimbusgb's reply, the limiting factor is not depth of wallet but the area available to mount panels. Purchasing domestic PV panels (the ones used by solar energy installers), is the cheapest way to get lots of watts - but they do need to go through an MPPT tracker or the like to reduce from 48 to 12 volts. If I was starting again I'd eschew 12v nominal panels. Also buying direct from the importers is a good idea - prices are about 65% of those you'll find on e-Bay and reputable manufacturers like Kyocera..
PSS Re flexible panels - cheap as chips, poor output, but less affected by shading - my two cost £80.
 
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Vonasi said:
The OP was asking about capacity for a sunny location. When you get further south you'll find that you have about four times more power than you can ever use - and some. It might be worth rigging up a cable and selling it to other people on the quay! Having said that the amount that they are starting to charge for electricity here in Greece now you might have the right idea. Only trouble is our 33 footer would sink under the weight of all those solar panels!
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Your opinions are interesting, if a little bizarre - on nearly all subjects.
 
Short answer to Nostros's question is as many watts as you can fit, you will always find a way to use that power!

We use two domestic 250w panels and see around 200 ah a day from them in the summer, cost (as Sam Tabs said earlier) was around £190 each. Something that is often missed is that a solar panel needs to be kept cool to be efficient, which is why a panel in the UK is actually more efficient that one in the mediteranean (although may not see as much sun!). Flexible panels glued to the deck are going to get a lot warmer than a free panel that allows air to circulate around them. Ours are mounted with a six inch air gap underneath them which makes a huge difference.
 
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Vonasi said:
The person I responded to was suggesting that 1000 Watts is needed. He is still in the UK, I am in the Med which is where the OP is. I have been using solar power here for over nine years and so speak from experience that 1000 Watts is serious overkill for these sunny climes. Not only is it overkill but with the average 100 Watt rigid panel weighing in at about 13kg a serious structural engineering project would be needed to support that 130 kg weight.
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Our 250w panels weigh 18kg each... We have 500w, If I had more I could save a lot of money on gas. As it is we use the inverter for the kettle, slow cooker, sandwich toaster and ice machine.
 
SeamanStaines said:
Our 250w panels weigh 18kg each... We have 500w, If I had more I could save a lot of money on gas. As it is we use the inverter for the kettle, slow cooker, sandwich toaster and ice machine.
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I know Nostro knows this, so for the benefit of any other reader; you do have a cat so the real estate to place panels, almost irrespective of weight, is less of a problem for you than for those of us with monos - especially the narrow *rsed variety :)
 
Nostrodamus said:
I had 140w of semi flexible which were on top of the saloon roof. The panels developed blisters and after only 2.5 years use will only work briefly in the morning and just before sunset. The company who made them (GB Sol were totally unhelpful and would not answer any of my questions about them or give technical support). I would never buy semi flexibles again even though they did offer to replace them at cost price plus VAT plus transport.
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+1 (although not about that particular supplier). I've had four different brands of semi-flexible panels, two allegedly 'top of the range'. None survived extended exposure to the Med/Carib sun. On the other hand every rigid panel I've had has carried on undaunted.
 
At the moment I am looking at about 380w of solar panels (4x95w)
I have found a company which have been the most helpful I have come across yet with very quick response time and good technical knowledge.
http://midsummerenergy.co.uk/index.html
They apparently bought out all the Kyocera panels when the Japanese company pulled out of the UK so can do them at discount.
 
I manage really well on 160 watts (from triplesolar on ebay), 2 x 80 watts panels on a stern gantry. Controlled by a dual charger from Sunpower which charges the house batteries first then the engine battery. It's important to use 6mm cable and connectors due to volt drop. The fridge is on 24/7 and so far not a problem. However I'm back out there in 1 1/2 weeks time, then I can truly gauge how well they perform in the autumn. The rear gantry cost €1000 which the 2 panels are mounted on, but looking at it, i could have got larger panels. I paid £1 per watt using domestic panels and was assured that they meet the marine standard by the supplier. He would have said that anyway!
 
Nostrodamus said:
At the moment I am looking at about 380w of solar panels (4x95w)
I have found a company which have been the most helpful I have come across yet with very quick response time and good technical knowledge.
http://midsummerenergy.co.uk/index.html
They apparently bought out all the Kyocera panels when the Japanese company pulled out of the UK so can do them at discount.
Click to expand...

I have Kyocera panels from Midsummer Energy. No problems whatsoever after around seven years.
 
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