Sizing my solar panel

[ashtead]

I went to Photonic Universe and bought a kit for £160 ish. No doubt I could have got something cheaper but I have read many good reviews and met them at the London boats show a couple of years ago. I persuaded my wife on the basis it was just over a hundred.....
I'm no boat electrician and don't get the more technical stuff so the gist of forum wisdom really helps my decision making.

For Ashtead

https://www.photonicuniverse.com/en...roller--regulator-for-12V--24V-batteries.html

With that I am told I could add 2 further 50W panels

Many thanks FWD - aI might follow your lead as I'm just dipping my toe in the solar water but might be able to rope in more tecky advice for others.

 

[Buck Turgidson]

So lots of "keeps my bank full' reply's - how do you know?

Not an easy thing to be accurate about.

Well I just use my phone and the vlctron app which shows per day time spent in Bulk/absorb/float. Wh from panel. Wh into the battery too.(the two are not the same).
Having left the boat for a month, when I came back I could see how much power the auto bilge pump had used keeping my leaky stern gland from sinking the boat which also helped me decide what to do about it. Could pretty much tell the daily sunshine hours from the times too.

 

[[3889]]

"IMO, for a fixed panel to be effective they need to be on a bimini, sprayhood or arch. Anywhere on deck is too often in the shade."
I disagree, my 20w panel was mounted on the coach roof forward of the hatch garage and so subject to shading from mast and boom. The boat was on a swinging mooring so no control over horizontal orientation. Despite this my batteries were always fully charged by next weekend and stayed charged for the weekend sailing.

A roof mounted 20W panel may well be suitable for your needs but does not provide a comparison with anything. I have used the same panel on both the coachouse roof and as a roaming panel left on the cockpit floor whilst away from the boat and the latter is more efficient without doubt.

 

[LittleSister]

a roaming panel left on the cockpit floor whilst away from the boat and the latter is more efficient without doubt.

Would a cockpit floor get much sun on it during a UK winter?

 

[Momac]

I just returned from a charter holiday in Greece. The boat had a solar panel.although I don't know what capacity it has.
In clear skies it was probably keeping up with the fridge but in shade was pretty worthless.
Even in Greece they have overcast skies occasionally. One day the weather turned a bit English and we had to run the engine to charge the batteries.