Solar panels positions & power

[gzahl]

I am thinking on installing a solar system on my DF 800 SW. I does not need to be completely autonomous, but it would still be nice. We don't need a lot of power - if it could power the refrigerator it would be enough.

Where do you have solar modules installed?
Are they fixed or do you only install them when needed?
What peak power do you have installed?
What kind of modules do you use?
Where do the cables run?

For now i was thinking either about one module behind the mast. But i don't have the measurements right now if an 50/60W panel even fits there?
A mobile solution only installed on vacations would also be nice. Is this something anyone is doing?
Thanks!

[Double Horizon]

How many amps does your refrigerator draw? Assume a 50% duty cycle (compressor on/off) x 24 hours. Then consider the rated power of the solar panels you need, and factor for the number of hours of peak sunlight per day, shade from rigging, clouds, and latitude.

Most “danfoss” type small refrigerator compressors draw about 3.2A at 12v. In Germany you probably need at least 150w of solar panels to be self sufficient, and a 200 amp-hour battery bank (assumes 50% draw-down and 100 amp hours usable).

[gzahl]

Thanks for the answer.
Of course i already did all of the theoretical calculations, estimated the solar input and so on. The small compressor refrigerators need about 5-10W, so about 12-24Ah/day or 0.5-1A.
I was more looking for some actual experience of someone, who is running such a system on a DF 800 and especially where they have mounted the solar cells - behind the mast, on the amas or use a "mobile" solar panel in the harbour.

[PerPedersen]

Bought my DF last year including a solar cell panel.

This is mounted fixed behind the mast and fits perfectly.

Only issue with that location is that when handling sail, boom etc you naturally want to step where the panel is, and I'm not sure it won't break even if it is a flat bendable type, so I avoid stepping on it.

[Steve B.]

I have never heard of a small refrigerator taking only ten watts. Are you sure about that?
I have a BD35 compressor (actually two) on my Dragonfly 1000.
The fridge has a smart thermostat so it draws about 5 amps on high speed and progressively less on lower speeds.
The second compressor is in a Dometic CF35 freezer under our berth.
It draws about 3 amps when running.
Multiply the anperages by 12 volts to get watt ratings.

[gzahl]

@PerPedersen: Do you know, how much power you can expect from it on average?
Is shading a big problem in that position?

@Steve B.: i meant the average power. Yes, it draws more power if it is on, but depending on the configured temperature difference to the outside temperature, it only turns on for maybe 5 minutes every hour.

[PerPedersen]

@PerPedersen: Do you know, how much power you can expect from it on average?
Is shading a big problem in that position?

I don't have any equipment using electricity, so I'm not so concerned with the charging, hence not sure about the output. That also answers your 2nd question: not a big problem for me