[C320-list] Solar panels and shading

[Timothy Woods]

Two years ago I installed two 100 watt flexible panels on my bimini and
haven't plugged in since. I connected them in parallel with a MPPT
controler and have no problems with shading when sailing. I'm in south
Florida and primarily use my boat during the winter months when the sun is
low. ( November till April.) We live full time on the boat for two to three
months at a time. At anchor or on a mooring I tie the boom off to the side
and get approximately 65 amp hours returned on a good day to the batteries.
The refrigerator is the biggest draw at 35 AH per 24 hours. We also watch 2
to 3 hours of TV and charge both cell phones.

I hope this helps, Tim

On Jan 30, 2018 9:22 AM, "Marek Fluder" <marekf at gmail.com> wrote:

> Last summer our docks were rebuilt so we had no power for quite some time.
> I played with a fixed 100W panel/controller that friend had sitting unused.
> I wanted to check the feasibility of sustaining the fridge running.
> In full sun with the panel fully perpendicular to sun rays and unobstructed
> it was able to "pump" 6.5A at 12.7V, so roughly delivering 82W.
> With the panel just sitting at a convenient and most optimal location on
> the foredeck it was producing 5.5-6.0A - about 70W.
> Any partial shade on the panel would drop the current substantially - I do
> not remember to what level, but it was dramatic.
> This setup was able to sustain the fridge running for a few days, but the
> battery voltage was dropping slowly so I have determined it is not
> sustainable in the longer run.
> I ran this test in second half of June which has the longest days.
> I hope this shed some practical light on this topic.
>
> Marek
> #1028
> Hamilton, ON
>
>
>
> On Tue, Jan 30, 2018 at 8:58 AM, <ptormey at 4square.net> wrote:
>
> > Well, I think you really do need to check with the manufacturer. They'll
> > have guidelines.
> >
> > Internal to a panel the cells are wired both parallel and in series to
> > achieve the voltage and amperage required (Power=Volts X AMPS). This also
> > protects failed cells from blocking the output.
> > In the old days it was common for some cells to be dead at manufacturer
> > and still perform within spec.
> >
> > My own unit (Suaoki 100W 18V 12V Solar Panel Charge) is 12-18 volts with
> > an XCSOURCE 30A 12V/24V Solar Charge Controller Solar Panel Battery
> > Intelligent Regulator LD296
> > Works fine on cloudy days and great on sunny days I keep it on the
> > 'flexed' over the Dodger which is, of course, under the boom.   It
> doesn't
> > do any heavy lifting like refrigeration but keeps the batteries fresh.
> > IF I wanted more power I'd parallel another 12-18 volt panel and let the
> > regulator do its job.
> >
> > It's hard to express the affect of shade without a constant load, but
> your
> > supplier should be able to put some parameters on it.
> >
> > Here is a good (simple ) article on the subject
> > http://www.mpptsolar.com/en/solar-panels-in-parallel.html
> >
> >
> >
> > Pat
> >
> >
> >
> >
>
>
> --
> ~~~~~~~_/)~~~~~~
>