T i m wrote:
On Mon, 19 Aug 2019 22:53:32 +0100, newshound
wrote:

snip

When I used to try to charge a leisure battery off a small panel to run
an intermittent stable light in the winter, the actual performance was
in the low single figures percentage, not actually worth doing. (Now I
just use a couple of camping lights with lithium batteries).

We currently have a 5W panel trying to maintain charge on a small
sealed battery (~16Ah) to run an electric fence (~50mA) round
daughters rabbit hutch from dusk to dawn (managed by the PWM charge
controller).

TBF, the panel isn't optimally placed ATM (temporary / test setup) and
so only get's any real / direct sunlight in the mornings, the end
result is even with all the sun we have been getting recently, supply
can't keep up with demand.

As the days get shorter and less sunny this will only get worse and so
I've either got to reposition the panel, add another panel or run some
light SWA out to the rabbits store shed.

I *think* it's reducing the rate at which the batteries get discharged
but when adding the panel I also swapped batteries (from 22Ah to the
smaller one).

Yes (OP here), I can see very little use for small panels except maybe
for maintaining very low consumption devices like simple phones.

We have three 'full sized' (i.e. 260 watt) panels on our boat which is
only a small (10 metre) boat and they are OK in the summer, in France,
to run a domestic fridge plus lights etc. Through the winter they
maintain the batteries (which is handy since I can remove the shore
power connection and thus reduce the corrosion risk).

I'm coming to the conclusion that even a similar sized panel (i.e. 250
watt or so) panel isn't going to run much of a pump all the year
round. Since just the panel will cost about £100 that's not a sensible
economic proposition.

--
Chris Green
·