Solar charging - Advice please

[chestnutree]

Hi all,

I have been searching on google and on this forum but i just need to know a little more.

The mooring i have for my new boat doesn't have electric hookup. I thought of using a petrol generator but i don't want to be making too much noise and annoying others.

I'm looking into solar power and have been looking at things i need to be able to set it up. The one thing im not sure on is the rating. Please could someone advise what the wattage needs to be from these solar pannels to keep my batteries topped up enough to just run a fridge and the water pump occasionally? as this will just be for daytime use at the mooring.

Thanks,
Nick

 

[noelex]

Welcome to the forum

It is a difficult question fridges vary enormously in their battery consumption and you don’t give your location.

If you want to run a fridge and water pump in the UK 24 hours a day on a mooring you will need about 50- 60 Ahrs.
In summer a solar panel of about 150 to 300 W will be needed.
In winter the fridge will use less, but your solar panels wont put out much and 200 to 350w will be required.

In a sunnier climate like the Med or the solar panel could be a lot smaller.

 

[chestnutree]

Hi,

Thanks for your reply.

I'm going to be moored at Shardlow on the river trent (nottingham/derby)

I say water pump..... it's really just for when the tap is turned on to wash hands, that will be about it. I'd say it's mainly for the fridge.

If it's still going to be up to around 300W, then thats going to be quite pricey :S

I might stick with a generator.

If the fridge was only turned on 2 - 3 days a week while the boat is occupied and the panels are left hooked up 24/7, whats the lowest wattage of panels you think i could get away with then?

 

[noelex]

That will help. You would need on average to generate 20AHrs a day (for 2.5 days a week fridge use) but the fridge will have to cool down the contents so you will use a bit more.
In the UK I would expect you will need 100-200w.
If you use a small well insulated fridge that will also help, but fridges use a lot of power and that’s tough to generate in the UK with solar.

 

[EddieBlue]

As a solar panel importer and retailer it is simply not feasible to think about running fridges from solar in the UK.

You could consider a conbination of a large bank of batteries, several panels and a wind generator but the cost would be daft just to run a fridge

Eddie

 

[Assassin]

Solar power is a contentious issue as many of the claims cannot be substantiated, and many owners install solar systems and find they are not doing what they claim. Sellers then blame the conditions, and get out of any issues this way.

This is not just confined to portable solar systems, but the solar farms around the UK which have been built at great expense to the taxpayer, these currently only provide 7% of their alleged output.

 

[Croak]

Freeze a couple of 2 litre lemonade bottles full of water at home. Then take them to the fridge, That will keep your milk cool for a couple of days

 

[longjohnsilver]

Hi all,

I have been searching on google and on this forum but i just need to know a little more.

The mooring i have for my new boat doesn't have electric hookup. I thought of using a petrol generator but i don't want to be making too much noise and annoying others.

I'm looking into solar power and have been looking at things i need to be able to set it up. The one thing im not sure on is the rating. Please could someone advise what the wattage needs to be from these solar pannels to keep my batteries topped up enough to just run a fridge and the water pump occasionally? as this will just be for daytime use at the mooring.

Thanks,
Nick

I installed a 100w solar panel last year and it keeps my 900AH battery bank nicely topped up. With the current long days and almost endless sun (fingers crossed!) I'm also keeping my fridge on even when away from the boat. It's a large domestic sized unit and whilst after a week away the batteries are about 10% down it only takes an hour or so with the genny to top them back up, so so far so good.
I'm on a trot mooring and my panel faces permanently south so gets most of whatever sun we have and it's angled at about 45 degrees. It certainly would be nowhere near as effective on a swinging mooring.
On a good sunny day I see a maximum charge going into the batteries of somewhere in the region of 4.5amps.

 

[Scubadoo]

I have a 11watt flexible solar panel placed on my dashboard which keeps it at an angle. It keeps the domestic battery topped up during the week. Fitted many years ago and still doing the job. But it would be some installation to manage a fridge installation, probably not worth it and costly.

 

[noelex]

Solar power is a contentious issue as many of the claims cannot be substantiated, and many owners install solar systems and find they are not doing what they claim. Sellers then blame the conditions, and get out of any issues this way.

Solar specifications on good panels, are usually quite accurate, but you have to understand them. For example the nominal output is given with a cell temperature of 25 C. So you have to look up the specification for a cell temperature of 40C which is more realistic.
There has been a thread recently where people have assumed the solar output will continue over 12hrs in the UK. These expectations are totally unrealistic and people with these preconceptions are bound to be disappointed.

 

[Assassin]

I do understand them, and the misleading claims made to sell them to many people, and is the reason i raised the issue.

Unfortunately they are not all like us, and the majority do not understand them.

 

[Cheekybrat]

Solar specifications on good panels, are usually quite accurate, but you have to understand them. For example the nominal output is given with a cell temperature of 25 C. So you have to look up the specification for a cell temperature of 40C which is more realistic.
There has been a thread recently where people have assumed the solar output will continue over 12hrs in the UK. These expectations are totally unrealistic and people with these preconceptions are bound to be disappointed.

worked with lectric most of my working life and know that solar and wind power just don't cut it at all.
Nick Heath

 

[Assassin]

Think i will stick with 2250 A/H twin battery packs, plenty of power here.

 

[noelex]

worked with lectric most of my working life and know that solar and wind power just don't cut it at all.
Nick Heath

Solar and wind do work very well at providing domestic power for boats. Like many cruising yachts, solar panels provide over 95% our electricity.