Solar Powered 12v 12w battery charger on offer.

Alternative Chioce ?

Prompted by this thread I paid Maplins a visit , intending to buy the same.
Looking at one i considered it too big for my small boat when deployed and when stored.
So I bought this one :-
http://www.maplin.co.uk/13w-solar-briefcase-99760
I know it's only 13w but it folds up and includes a regulator for £49.99
For my single 90ah battery I probably don't really need a regulator but now I have one if I ever buy a more powerful panel.
I will site it under the spay hood (I have big windows in mine) when off the boat and outside the spray hood when I am on the boat.
The fact that it folds up is good for me when it's not in use since space is always an issue on a 24 footer.
 
salinia said:
I have mine in the garden at the moment charging my battery it is connected to the solar charger. I tested the output with my multimeter from the charger via the regulator and was initially disapointed with a low reading (I do not understand how these things work) however when connected to the battery all was fine and it was charging. I will make a video and post it here back in a few minutes.

http://www.youtube.com/watch?v=Er49hCKSNV0&feature=player_detailpage
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The fluctuating readings are because the regulator is confused by not having a battery connected.

Try switching your meter to current, and put it in series with the battery. I would be interested in the charging current.

The low readings I have seen so far show that there will be no risk of boiling the battery, and a charge regulator is IMO unecessary.

Indoors, behind the workshop window, I can get up to 600mA (about 7W) charge when the sun is out, but as soon as the sun goes behind a cloud it's down under 200mA or less (no more than 2W)

I'm doing my tests indoors behind a window as that's how I'm going to use it initially on the boat. Any thoughts of mounting it outside is a winter project, not something to try and do afloat.
 
Just got back from installing my two on the coachroof. Very little sun but quite windy and boat moving around a lot so difficult to get a stable reading.

Best 1.2 amps, worst 0.45.

Very pleased with that as over a week given typical weather , some sun some cloud, I expect to get 12 hours x 7 days x '0.8' amps , 76ah.

At a total cost of < £100 including regulator , 10 amp fuse and holder, some choccy blocks and wires.

Salinia: interesting video but why were you measuring volts? Does this convert into amps in some mystical way?
 
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Bav34 - "Salinia: interesting video but why were you measuring volts? Does this convert into amps in some mystical way?"

Measuring volts I think so? As a rule of thumb my idea was to measure the battery with nothing attached to it and get a reading in volts and then connect the solar charger up attach the multimeter and see if the reading is higher than the one previous..it was a little so I determined that the battery was charging. I will have to read up on it all this electrickery is facinating stuff wish I understood it better...I didnt know what a diode did untill yesterday. I have a DCmA setting on my multimeter perhaps I should give that a go:confused:
 
salinia said:
Measuring volts I think so? As a rule of thumb my idea was to measure the battery with nothing attached to it and get a reading in volts and then connect the solar charger up attach the multimeter and see if the reading is higher than the one previous..it was a little so I determined that the battery was charging. I will have to read up on it all this electrickery is facinating stuff wish I understood it better...I didnt know what a diode did untill yesterday. I have a DCmA setting on my multimeter perhaps I should give that a go:confused:
Click to expand...

The voltage will increase as the battery is charged, but only slowly. My battery has gone from 12.39V to 12.61V today, with the panel indoors close to the window in my workshop. You won't see an immediate increase as soon as you connect the panel.

But yes, switch your meter to mA and try it in series with the panel and battery. Remember many meters require the probes to be inserted into a different socket for current than the normal one used for volts and ohms.

I'm going to leave my panel set up near the window for a week to simulate being inside the boat hung up right next to the window for a week between outings, and see how high the voltage gets.

There's some interesting facts here about charging lead acid batteries http://www.scubaengineer.com/documents/lead_acid_battery_charging_graphs.pdf

See the graph on page 2 of that document.. the "c/40" graph plot is the most applicable, since we are talking of a very low charge rate. So my battery has gone from 12.39V (25% charged) to 12.61V (35% charged) in a day. So that's 10% of the batteries 55Ah capacity or 5.5Ah of charge received today.

Actually I doubt it's received that much charge, but it gives some indication. It just shows (as explained in that article) how difficult it is to measure the state of charge of a battery.
 
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So all in all people seem pleased then? I quite fancy one just to keep my batteries topped up when the boat is unused...I have an inboard so no problems charging if I need to with the engine.

Is it a bit of a "no-brainer" at that price or should I be spending more for increased output/durability?
 
I bought one of these at Maplin's previous sale during the winter and tried it for the first time on the boat a couple of weeks ago. Swinging around at anchor in bright sun with the solar panel tied onto the stowed sail on the boom, angled roughly perpendicular to the sun, I got a charging rate of around 0.6 A when pointing in the optimum direction, falling to 0.1 A when not in direct sunlight. About what I would expect, so quite pleased.

I have shore power while in the marina so have no immediate plans to install it permanently, but for extended trips it could be quite useful deployed temporarily, particularly in sunny early mornings or evenings when I would hope to collect 1 Ah or so. Small, but not useless. For this sort of occasional use I feel a regulator is unnecessary.
 
Can someone help me out please:

I fitted my panel in the boat today. but it din't quite fit where I expected it to, so I need to make a bracket for it.

Trouble is, panel is now on boat, and I'm at home.

So can someone with one of these plese give me the overall dimensions of the panel, and more importantly, the exact centre to centre dimensions of the 4 mounting holes (in both planes)

Thanks.

P.S offer has now finished and back up to full price.
 
Bav34 said:
External dimensions: 98(l) x 34(w) x 1.5(d) cm
Panel dimensions: 90(l) x 29(w) cm

from

http://www.maplin.co.uk/solar-powered-12v-12w-battery-charger-217850

If you want I'll go out to my boat and get the other figures for you tm

?
Click to expand...

Don't go out of your way to get the info, I can drive to my own boat to measure it.

It's the spacings of the mounting holes that are not on the website that I really need, so whoever gets the chance first I would appreciate if you could measure them.
 
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