Solar panels

[gjeffery]

I want to fit solar panels with a capacity of 15 watts, mainly to charge my battery at the mooring. I would be grateful for any advice concerning suitable battery charging regulators, and especially for any validated circuits to enable me to build one.

 

[byron]

I would be interested to know if those solar panels that plug into the ciggie lighters will work on a boat too.

http://www.alexander-advertising.co.uk

 

[quaelgeist2]

Unless you have a very small battery, it should work by directly connecting the panel to the battery.

Just in case, check that your panel has, like most others, a diode preventing reverse flows when charging with the engine

chris

 

[brianrunyard]

December issue of Motor Boats Monthly, has an article on this.

Brian
http://homepage.ntlworld.com/brunyard

 

[bedouin]

They should do. After all the ciggie lighter is just a convenient way of connecting the solar panel to the battery. How you do so shouldn't matter.

 

[davidbains]

I read somewhere that 5watts was enough to trickle charge in the Med, and 10watts in northern Europe. At this power level you don't really need a regulator. Just a blocking diode to prevent discharge into the panel at night. The blocking diode can be found for pence in Maplins. They also sell the auto panels but I suspect these are designed to be left on a dashboard and won't last long in the sun and rain. I have a 12watt panel from Sunware ( who have a website). They are not the cheapest but IMHO the most robust for deck fitting.
Anything more than ten watts should be regulated unless you live aboard with a fridge running.

 

[yoda]

All my domestic requirements are run from 2 batteries only fed by a 10w solar panel via a solasum regulator (about£35) I have a changeover switch in the output to select the battery being charged. Works a treat. I have also taken to using one of the car trickle charge pannels on the engine bateries and it seems to just keep them from draining in the winter months.

Yoda

 

[VicS]

My 5 watt panel (charging a 45 ah battery) is one of the best bits of kit I've bought.

This does not need a regulator but the panel suppliers (check the web sites) will advise on the need with a 15w panel and what ever size of battery you have.

You could save money by trying it without a regulator and if the battery shows no signs of overcharging then leave it at that.

Whether you fit a regulator or not FIT A FUSE as close as possible to the battery.

 

[smb]

I think it depends on your setup and what you want to achieve. On my boat the lighter socket is downstream of the masterswich, so to get a charge from a solar panel I would need to leave the masterswitch in the on position otherwise the only things receiving free juice from the sun would be all those things I intended to isolate from the supply in the first place.

Steve

 

[colinroybarrett]

Gordon,

There is a lot of interest in Solar, under “alternative power” in the UsofA, I would suggest you look around the Web, for more technical assistance.

The general opinion seems to be that; unless your solar capacity exceeds 10% of your batteries, you’ve no need for regulation, particularly in the UK.

Keep an eye on the fully charged voltage in high sunshine, no lead/acid battery should be allowed to rise above 13.8v at 20deg C, (more for lower temp, less for higher). Much above this and excessive gassing will occur and the batteries will have a greatly reduced life.

Solar panels are quite happy to be short-circuited, so if you decide to build your own regulation (Why? RS sell these cheap enough anyway) you simply need to clamp the output at, say 14v at the panel, before your blocking diode, which should leave you with about 13.4-13.8 at the batteries.

Cell arrays; series-parallel wired, will always suffer from any shadow falling upon them, any one cell not producing; will simply absorb, or not pass current for the whole of the rest of the string, so shadow losses are much greater than you would expect.

My experience of “cheap” panels is they are often made from cells rejected during manufacture, if it looks like a jigsaw puzzle of bits, laced together with thin flat ribbon cabling, I doubt if it will have a long life at sea. Vyv Cox has written a good article on fitting Solar Panels (to keep his Gin cold - See my Web-Site link below).

Good luck with this, send me a ‘private message’ as I have (somewhere) a load of documentation about Solar Panels and regulation.

Cheers,
Colin & Urszula Barrett
<A target="_blank" HREF=http://www.kahawi.co.uk>http://www.kahawi.co.uk</A>