Solar panel

[Slow_boat]

I bought a small (1.5w) solar panel at the Maplin sale yesterday. The idea is to keep the batteries topped up while I'm away from the boat. It has a cigarette lighter type plug or crocodile clips.

As I have two batteries, I assume I'll have to use the cigarette lighter to plug it in but will I have to switch the battery switch to the 'Both on' postition for it to work?

 

[sarabande]

are your boat batteries separate or connected ?

If connected (e.g. parallel) then stick one clip on the pos of one batt, and the other clip on the neg of the other.

If separate batts, then I'd be tempted to just charge one of the batteries and ignore the other.


1.5 watts is not a huge charge even in amps In fact it's quite dinky so no regulator required. Do you know if it fitted with a diode to prevent the batteries warming the solar panel at night ?

 

[VicS]

Unless you have very small batteries 1.5 watts is probably too small to charge two


I think id buy another panel and connect one directly to each battery and leave the isolator switch off.
Not the best idea to leave them paralleled nor to leave the isolator on.

Fit in line fuses close to the batteries.

Alternatively charge the batteries alternately. A month at a time will do

 

[elton]

A panel that small will just about provide a maintenance charge sufficient for one battery. Be sure to fit an in-line fuse close to the battery connection to prevent fire in the event of a fault or damage to the cabling.

 

[vyv_cox]

I suspect that the effect of 1.5 watts on two reasonable sized batteries in the 80 - 110 Ah range, will be undetectable. I use one 10 watt panel per 110 Ah battery on my camper van, no regulator.

 

[CAPTAIN FANTASTIC]

Do you mean 15watt? because 1.5 watts is far too small to make any difference whatsoever.

 

[VicS]

Do you mean 15watt? because 1.5 watts is far too small to make any difference whatsoever.

One of these I would have assumed ( £9.99 instead of £19.99 )

http://www.maplin.co.uk/solar-powered-12v-1.5w-battery-trickle-charger-98358

.

 

[colind3782]

One of these I would have assumed

http://www.maplin.co.uk/solar-powered-12v-1.5w-battery-trickle-charger-98358

.

That looks like the one I bought some time ago for a different, but similar, job. Completely useless.

 

[haydude]

I suspect that the effect of 1.5 watts on two reasonable sized batteries in the 80 - 110 Ah range, will be undetectable. I use one 10 watt panel per 110 Ah battery on my camper van, no regulator.

I agree.

I have a 65W panel fitted on the foredeck. In the summer I get 4.7 Amps top, and now it struggles to provide up to 1Amp.

A 1.5W panel supplies 0.125 Amps at 12V top. But then you have to account for wire length and size that will take up to 10% off. Also in winter the panel will supply 1/10th of its peak Amps for just a few hours, which is nothing to a lead acid battery. Since those small panels most probably do not have a diode, it is more likely that it will discharge your battery at night.

I think that for a trickle charge you need a 10W panel as minimum.

 

[Slow_boat]

That's the kiddy!

Maybe I should have bought the 15w one. Ho hum.

 

[Robin]

Take it back quick?

 

[ghostlymoron]

A 1.5w panel won't really provide a worthwhile amount of charging especially at this time of year. I would return it if I were you and put the money towards a proper installation. Your panel is not waterproof either and probably won't last long on a boat.

 

[Searush]

I use one of those on the boat & leave it under the sprayhood window. Connected direct & with good light, it will keep one battery from slowly discharging over the winter. Swopping batteries is OK, but I usually decide whether to swop over by checking on the voltage when I arrive.

I bought another for the motorhome, but it is parked in the shade & it doesn't get enough light to keep the battery up to snuff. It probably needs a bigger one on the roof so I will probably transfer it to the boat & get a bigger one for the van. 10 squid is a reasonable price for what you have, 20 squid is silly.

 

[Robin]

It might keep a beard trimmer battery up?