Solar Panel Requirments

[monkfish24]

I've got a racing yacht and a single battery, I have no engine to start so can supply all my electrical needs with one battery, supplying one chart light (which I will go down the LED route with), a speed and depth display and I may add a CD/radio later on. I'm not sure of the current draw of any of these items yet as I haven't bought them

If I buy this Solar Panel, which it says I will not need a charge controller with for a Battery over 70ah. Is this correct?

http://www.google.co.uk/products/ca...=X&ei=bQpiT4fXM9G58gPCxcShCA&ved=0CJcBEPMCMAA

EDIT: Just started looking into that SP, it charges UP TO Approx. amp-hours/day** - 4.62 based on 7 hours of light....

So if I have a say 72ah leisure battery, with this solar panel connected straight up, am I going to be ok or is there a severe risk of overcharging? EDIT: NOT REALLY

Thanks in advance!

 

[ghostlymoron]

It's unlikely that you'll fry your battery with a 10w panel but at the cost of about £10 why not install a simply regulator. It'll show if it is charging and also if the battery is fully charged. The panel that you are considering doesn't look fully weatherproof to me. You may be better getting one that is made for the harsh marine environment and semi-flexible so that you don't break it if you tread on it - more money though.

 

[BAtoo]

I've been told that solar chargers up to 10w are ok without a regulator but the simple regulators are quite cheap & will prevent overcharging in the glorious summer we are about to have...

I bought my 20W panel last year off ebay for about what is indicated on the link - might be worth looking around...

 

[pappaecho]

The answer to the solar charge controller is ... depends. If you have a panel sufficiently big to overcharge the battery then you need a controller.

Perhaps a better way of looking at it, when do you want to use the boat? If it is 12 months a year, then you will need a bigger panel to ensure adequate charge during the winter. If you only say want from March to October, then a smaller panel will be OK.

another possible consideration is the way the boat is moored. If it is moored in a fixed position, on pontoon or fore and after mooring then you can site you panel facing south.
If on a swinging mooring, then you will have to put up with the panel being pointing in nay direction, which will mean less solar collection, and then you will have to flat the plate effectively flat, which fives some solar gain, but is far less efficient than a panels angled at 30-40 degrees facing south.

Probably one way forward is to talk to others in your locale who have solar panels. them. For a 75 amp hour battery I would guess a 20watt panel will suffice subject to the above

 

[VicS]

I've got a racing yacht and a single battery, I have no engine to start so can supply all my electrical needs with one battery, supplying one chart light (which I will go down the LED route with), a speed and depth display and I may add a CD/radio later on. I'm not sure of the current draw of any of these items yet as I haven't bought them

If I buy this Solar Panel, which it says I will not need a charge controller with for a Battery over 70ah. Is this correct?

http://www.google.co.uk/products/ca...=X&ei=bQpiT4fXM9G58gPCxcShCA&ved=0CJcBEPMCMAA

EDIT: Just started looking into that SP, it charges UP TO Approx. amp-hours/day** - 4.62 based on 7 hours of light....

So if I have a say 72ah leisure battery, with this solar panel connected straight up, am I going to be ok or is there a severe risk of overcharging? EDIT: NOT REALLY

Thanks in advance!

One common rule of thumb is that if the solar panel does not exceed 1 watt per 10 Ah you do not need a regulator but one is advisable regardless of this for panels in excess of 10 watts.

So 10 watts into 100 Ah is the limit.

10 watts into 70 Ah is best with a regualator ... or you will find the battery needs its electrolyte topping up rather more frequently than it might otherwise. A non-sealed battery is then vital.

A cheap regulator eg from Maplin will disconnect once the volts have risen to a certain level and reconnect when they fall.

A pulse width modulated regulator (PWM) will give a more graduated control of the charging rate.

A "maximum power point tracking" regulator (MPPT) will control the panel at is optimum output .. usually around 16 volts, and convert the extra volts into amps by electronic wizardry.

 

[monkfish24]

Brilliant, thank you everyone!

Just to answer a few concerns, I'm going to make a frame to support it under the hatch which is completely perspex, this should hopefull protect it and stop it being trodden on by clumsy people like me It will slide forward from under the hatch whilst sailing so it is out of the way and stowed some where so as not to get damaged.

Will this cause much loss in power generated if it is under a pane of perspex?

Yes, i think a regulator may be the answer with a slightly larger Wattage on the solar panel, however I don't want it too big as I will not have anywhere to fit it. the boat is only 23ft in the first place.

Ok, so revised set up, 70ish ah battery with a regulator linked to a 20w solar panel and that should provide for my needs

 

[E.T.]

i fitted a 30 W panel last week from solarbright.com in norwich.

real quality kit. has a walkable surface, so its on the roof next to the companion way hatch.

the controllers are encased in resin (if you buy their marine version)

customer service is fantastic

not the cheapest. . . but its the old story about getting what you pay for.



when you consider the cost of electrical hook up in a marina this will pay for itself in two years!

 

[viago]

i fitted a 20 watt panel recently to charge a 110 and a starter battery. the regulator from maplins which supplies regulation to both measures about 70 x 50 x 20mm so you should be able to easily fit one in or around the battery compartment. apparently the closer the better. it is keeping me nicely topped up.