5w solar panel

[hurley]

Hi Just looking for a bit of advice please.

Do I need a voltage regulator for a 5w solar panel. It will be connected to an 85 hr Leisure battery. It will be connected for upto a week at a time on a swinging mooring.

Thanks Nick

[stevebrassett]

If it has a built-in diode to prevent discharge, it will not need a regulator. I used mine for over a season like that with no problems.

[simonfraser]

you can put 10% of the capacity of the battery in with a solar panel without using a regulator, so no.
you'll get more out of your panel if you mount it near vertical pointing south, side of the cabin is much better than the top.

[VicS]

[ QUOTE ]
Do I need a voltage regulator for a 5w solar panel. It will be connected to an 85 hr Leisure battery

[/ QUOTE ] No not at all. I have used 5watt panel with no regulator connected permanently to a much smaller (40 or 45 Ah leisure battery) However a 5 watt panel might just be a tad small for a 85 Ah battery. I note Maplin recommend 10watts for a 70Ah, although I dont really see why.

As others have said check that it has a blocking diode to prevent discharge at night.

Also connect the panel to the battery via fuse rated to protect the wiring.

[hurley]

Cheers Guys, for your prompt help !

I will go for it !

Regards Nick

[William_H]

On a swing mooring you are likely to have the panel pointing at the sun only a portion of the day so actual Amp hours produced will be a lot less than for a boat in a fixed mooring. So certainly don't need a regulator.
Regarding the blocking diode. You can test if you don't know if one is fitted by connecting a milliampmeter (multimeter on current) between on lead and the battery. You should be able to measure the actual current into the battery at the time about 250 milliamps (1/4 amp) is good.
Now cover the panel so it is in darkness. The current should drop to zero but show no reverse current. (switch the meter to the most sensitive range. No current means it has a blocking diode (most have them fitted) good luck olewill

[rogerdog]

As already stated will be fine (most contain the blocking diode - but worth checking as detailed before) however it is on the small side. Don't forget that the 5W output is under ideal conditions - so you are unlikely to see this averaged out over a day (even without cloud etc)

[Relax]

If you look at 'the book' (Calder) he recons you can get away with 0.5% capacity unregulated (AHr cpacity viz panel capacity) and that 0.3% is ideal as a float charge for the battery - to prevent discharge.

I have a tiny (think they are 1.5W Maplins panels) attached directly to each of two 85 AHr batteries and they keep the charge up fine - though I doubt they would actually recharge the battery.