Solar panels indoors!

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richardsnowstar

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I have been thinking of getting some solar panels to keep my batteries topped up now that I am on a mid stream pontoon mooring. I do not want to fix them permanently to the deck or coachroof. I was thinking of getting a flexible panel that I can put away when I am sailing but am worried about a few hundred pounds worth of panel getting nicked. My boat has large windows so I was wondering about rigging the panels inside the boat when on the mooring.

Does anyone know if the solar panel will still work through a glass or acrylic window?
 
Solar panels behind acrylic

Yes they will still work behind acrylic but with some losses. I would suggest you try the panel using an amp meter. You will need to have window facing south at suitable angle. You might be disappointed at results due to high latitude and bad weather but it should still be useful.
Alternatively you might be able to use some rigging wire or chain and padlock to provide some security.
I just bungee my small panel onto the top of the boom and mainsail and unplug and remove when I go sailing. good luck olewill
 
A thought.

VW/Audi have a solar charger which plugs into the 12 Volt outlet. If all you wish is to keep your batteries topped up, this could be a solution?

However, Pegasus has a large flexible panel permanently attached just forward of the companion way. Weighs 10 kgs max and keeps batts at 100% and helps keep the beer cold (does better now that we have a Frigoboat with keel cooler) ... lots of dosh though.

GL
 
That's exactly what I have on my boat, a solar panel inside the window.

I did that because I haven't found anywhere to fix it outside that wouldn't look rediculous.

It looks straught out of an east facing window (when in the harbour) so gets direct moring sunsine.

It appears to do it's job of keeping the battery topped up for our sailing trips, last season I never had to take the battery home for a proper charge.
 
Richard, this what my parents do in their motorhome. They have one of the suitcase style panels which folds up when not in use. Theres is 13w (there are also smaller 4w versions) and keeps the batteries topped up nicely all be it with some losses throught the tinted windows.

Pete
 
Richard
I used a solar briefcase last winter inside my wheelhouse.
Charges 12 or 24v up to 13 amps.
In fact I was just about to put it on Ebay as I now have permanent panels on my wheelhouse roof.
Interested? PM me.
 
If you just want to keep your batteries healthy, you don't need to spend hundreds of pounds. We used one of these http://www.maplin.co.uk/solar-powered-12v-12w-battery-charger-217850 at less then £40 on our previous boat and the batteries stayed topped up all the time. I didn't mount it permanently - just propped it up on the cockpit floor at approximately the right angle to maximise solar exposure and used a couple of thin bungee cords to stop it flipping over in the wind.

I used one of Maplin's charge controllers - http://www.maplin.co.uk/dual-16a-solar-charge-regulator-266145 to split the charge across the domestic and engine batteries - worked fine and the total bill was about fifty quid!

The panel is low output and only good for protecting the battery against self-discharge. On our new boat, we leave the fridge running most of the time and no panel costing less than several hundred will cope with that, so she stays on shorepower.
 
Given the vagaries of the English weather, would that Maplin panel recharge a 12v battery from one weekend to the next? I..e if the battery is used one weekend, unused (no drain) for five days and then be fully charged by the following weekend?
 
Highndry said:
Given the vagaries of the English weather, would that Maplin panel recharge a 12v battery from one weekend to the next? I..e if the battery is used one weekend, unused (no drain) for five days and then be fully charged by the following weekend?
Click to expand...

No, we are not in that league, we are talking about a small panel top up and protect the battery against self-discharge. Not re-charging after heavy use.
A friend of mine has a small panel on his boat, inside a south facing window.
It has helped significantly, most noticeably with better engine starting during the winter.
It should easily pay for itself by making the batteries last longer.
 
Highndry said:
Given the vagaries of the English weather, would that Maplin panel recharge a 12v battery from one weekend to the next? I..e if the battery is used one weekend, unused (no drain) for five days and then be fully charged by the following weekend?
Click to expand...

It's a 12w panel so it will produce around 1A in bright sun. Even in cloudy sun, it will produce upwards of 0.25A around midday, though this will drop off early morning and late afternoon. In the summer with long days and a fair amount of sunshine you should be able to hope for 4 or 5 amp-hours per day - more in really good weather - multiply by 5 and you could hope for 20 to 25 AH per week. Is that enough for you? If you also run the engine for an hour or two during the weekend, probably so.

The figures in winter will probably be a lot less - if only because the days are shorter - on the other hand, most people sail a lot less often in the winter, so it will have longer to recover. We used this panel on a Hunter Ranger 265 and we normally came back to the boat to find the two batteries fully charged. We did, however, have shorepower available, so if we stayed on the boat overnight we would not significantly discharge the battery. We also are moored well up a narrow river and would generally have run the engine for half an hour or more on our way back.
 
I may have overstated the likely drain on my battery over a weekend. My boat is on Rutland and the only likely power drain is with an electric outboard for getting in and out of the mooring or if we become becalmed and have to motor back (max one hour use). I currently take the battery home and put it on a charger between sails. I'm just wondering if a solar panel might mean I can leave it on the boat.
As a matter of interest, if I did want something to recharge a 100A 12v battery from an almost discharged state, what sort of wattage would I need to be looking at?
 
Highndry said:
I may have overstated the likely drain on my battery over a weekend. My boat is on Rutland and the only likely power drain is with an electric outboard for getting in and out of the mooring or if we become becalmed and have to motor back (max one hour use). I currently take the battery home and put it on a charger between sails. I'm just wondering if a solar panel might mean I can leave it on the boat.
As a matter of interest, if I did want something to recharge a 100A 12v battery from an almost discharged state, what sort of wattage would I need to be looking at?
Click to expand...

100Ah to recharge in 5 days say.
Estimate 4 hours sunshine per day ave?
So that would be 20 hours, so 5Amps needed, or 60W.
But your panel will not be ideally aimed most of the time, so you might need to double that!
It depends on whether you want something to work on an average week, the worst case or something in between.

A small panel that allowed you to only take the battery home if it had seen heavy use might be a more cost-effective goal.
 
Highndry said:
I may have overstated the likely drain on my battery over a weekend. My boat is on Rutland and the only likely power drain is with an electric outboard for getting in and out of the mooring or if we become becalmed and have to motor back (max one hour use). I currently take the battery home and put it on a charger between sails. I'm just wondering if a solar panel might mean I can leave it on the boat.
As a matter of interest, if I did want something to recharge a 100A 12v battery from an almost discharged state, what sort of wattage would I need to be looking at?
Click to expand...

I assume you mean a 100AH battery. If you ran it completely flat you would need 100A for 1 hour or 1A for 100 hours or .....

So, if you have the whole week to recharge, you need to pump in about 20AH per day - middle of the summer you get eight to ten hours of fairly strong sunlight so you want to average a couple of amps output across the day - that's 24w average - put in about 50w of panels to give you some headroom. Those are all rather speculative figures, but you get the idea, don't you? Four of those Maplins £40 panels should have a fighting chance of managing it in mid summer - performance will obviously drop off considerably as winter approaches.

HOWEVER! If you were to draw all 100AH out of your battery too often, you would kill it anyway, so you probably need a fair bit less charging capacity...
 
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