How much power from Solar? In the uk.

[andsarkit]

That works will it gives me a yield of about 0.3 kWh per day. Can some one give me that in a useful unit?

eg amps/hr. google gives me 25 amp hours/ day.so maybe 1/3 of my requirement?

0.3kWh = 300Wh
Watts = Amps x Volts
So for a 12 V battery: 300Wh/12V = 25Ah
Google is correct

 

[samfieldhouse]

Each summer - July/September I spend around 8 weeks off grid between Chichester and Dartmouth.

My two 100w panels keep my fridge going constantly and my laptop charged to enable me to work 4 days a week, full time.

There’s also the usual phone/tablet charging etc.

My engine doesn’t charge my domestic battery at all.

Hope that’s helpful?

 

[Laminar Flow]

We spend 4-5 months a year living and cruising aboard our boat. We run a fridge 24/7, the usual navigational instruments, cabin & nav lights, charge our devices and run the occasional tool off the 12v system. At sea and on passage, we use the AP. Some passages are two to three days long, more often then not in lively seas, when the AP gets a proper workout and not necessarily with a charging station at the other end. We anchor out and often or sail in places where there are no shore based charging options. Our boat is a ketch, which makes shade free solar installation a near impossibility.

Our initial electrical power installation consisted of one 100 Amp/hr house battery charged by shore power or by engine via the alternator with 50 Amps. This we augmented with a suitcase generator.

This setup proved to be entirely inadequate for our purposes and not running the fridge is, in our case, entirely not an option for very pertinent reasons (not a joke).

According to my research, the rule of thumb for solar output in Northern latitudes around 49 degr. is:
4 x nominal watt capacity per diem, on average, from Spring to Fall.

Our next step was to install 300 W of solar on the wheelhouse roof, using 6 small panels of 50 W to reduce shading losses. This we combined with a considerably larger MPPT charger than required, as to keep our options for possible expansion open.

Importantly, we increased our battery capacity to 400 Amp/h.

This arrangement completely changed our cruising life and we are now entirely autonomous from shoreside facilities or having to run the engine, never mind the suitcase generator, for charging purposes. Initially, I used to tie off the boom to the side and fiddle with various lines to reduce shading. I no longer bother. On a sunny day, the batteries are fully charged by 10.00 in the morning, on a cloudy day by 14.00 at the latest. In late October, in Holland and with the Webasto running full time (frost at nights) solar was starting to reach it's limits.

For last year's 2500 mile trip to the Shetlands, we added two more flexible panels, of 120 W each, to the Bimini top in anticipation of reduced sun hours.
In addition to all the usual consumers, we kept the heating going throughout, to keep the boat dry and comfortable and made long, multi day passages under AP, in challenging conditions and under sail only, no matter the weather. Never had an issue with keeping the batteries charged.

We love solar and compared to any other option it is now as cheap as chips. Wind power, with which I have plenty of experience in long distance cruising, is not worth the money by comparison.

 

[AngusMcDoon]

.

 

[Neeves]

Each summer - July/September I spend around 8 weeks off grid between Chichester and Dartmouth.

My two 100w panels keep my fridge going constantly and my laptop charged to enable me to work 4 days a week, full time.

There’s also the usual phone/tablet charging etc.

My engine doesn’t charge my domestic battery at all.

Hope that’s helpful?

Interesting

So how do you charge the domestic batteries, water pump, lights, nav lights, chart plotter, windlass (which would normally be wired to the domestic (or house bank) and when you do run the engine - you imply it only charges the engine start - seems a bit wasteful of a potential resource. Recalling UK weather then 3 days of overcast skies would mean no replenishment to maintain the fridge -

Jonathan

 

[ctva]

What an astonishing dogs dinner of mangled, garbled and plain imaginary units this thread contains!
A little understanding of the most elementary basics of electricity and power consumption are necessary before any coherent discussion can thake place. (With apologies to those who do understand the units involved).

This is a forum, so rather than saying that everyone is talking doggy doo doo, why not help the op and regale us with your obvious wisdom?

 

[Beneteau381]

What an astonishing dogs dinner of mangled, garbled and plain imaginary units this thread contains!
A little understanding of the most elementary basics of electricity and power consumption are necessary before any coherent discussion can thake place. (With apologies to those who do understand the units involved).

Pedants shouldn’t make spelling mistakes!

 

[Sandy]

I installed 200 watts of solar at the tail end of last season. Here are my figures over the winter. The panels are vertical east facing while the boat is on the hard.

 

[geem]

I installed 200 watts of solar at the tail end of last season. Here are my figures over the winter. The panels are vertical east facing while the boat is on the hard.

View attachment 174834

Interesting to see the performance of solar in the UK. We will be back to that later this year. We run 920w of solar. Yesterday here in Antigua we harvested 4.3kWh from all the panels. That's about as good as it gets for us.
Our best performing panels are the ones we can tilt towards the sun. These are a pair of 180w panels wired in series. Mounted on the guardwires.
You can see from the photos from our Victron MPPT that this week, the maximum output has peaked above the rated 360w a few times.
Not relevant to the UK solar output but thought people might be interested in the difference solar makes out here. Wind turbines are pretty much a waste of time here as solar is so much more effective

 

[Laser310]

Our best performing panels are the ones we can tilt towards the sun. These are a pair of 180w panels wired in series. Mounted on the guardwires.

can you post a pic of this setup?

 

[geem]

can you post a pic of this setup?

I swapped the last two aluminium stanchions to s/s so I could install a 1" s/s tube. This gives a nice mount for the panels. Plastic clamps rotate on the s/s tube nicely. I installed s/s angle on the panel frame to reinforce the mounting point. Notched timber works great for adjusting the angle of the panels. A couple of bits of string tie down the panels when sailing. At anchor we don't need the string.

 

[Laser310]

Did you always have rigid guard rails?

Or, were they originally wire, and you converted to pipe for this installation?

It looks like the panels stay in place while sailing - right?

how big is this boat?

 

[RunAgroundHard]

Did you always have rigid guard rails?

Or, were they originally wire, and you converted to pipe for this installation?

It looks like the panels stay in place while sailing - right?

how big is this boat?

This might give you and idea. I used 1” stainless tube and end caps to make solid rails on the quarter secured to the stanchions. The guard wires are still there. Bought from Sheridan Marine.

Canopy Fittings - Sheridan Marine

No doubt there are other ways to achieve the same result.

 

[Sea Change]

Did you always have rigid guard rails?

Or, were they originally wire, and you converted to pipe for this installation?

It looks like the panels stay in place while sailing - right?

how big is this boat?

We've got a similar setup. 39ft boat with relatively high freeboard. The panels stay in place at all times except when coming alongside, when I drop them to make it easier to do warps etc.
I initially hung mine from the guard wires directly, which was fine. I later added steel tubing but that was really to brace my bimini.
I don't have a support prop, my panels are lifted using lines from above. I already had a defunct wind turbine pole and an aerial mast in the right places. Another line pulling down to the toerail stops the wind from getting under the panels and flipping them.

 

[onesea]

This is a forum, so rather than saying that everyone is talking doggy doo doo, why not help the op and regale us with your obvious wisdom?

Cause it's obvious right some of us ain't intelligent enough to understand.

Maybe it's because there are more variables than one could calculate.

The fridge has been working harder the last 36 hours as it's being cooling down some thermal mass to make it more resilient when it's out of power (I filled the fridge with beer ).

However I have upgraded my PWM controller to a MPPT. It gives lots of numbers that I don't understand either



However it does seem the more load you apply the more the solar can harvest. To me that makes sense lead acid batteries have more resistance when full.

Time will tell, the fridge is wired into the solar controller along with a couple of USB sockets.

That way I can control the voltage they turn off at, leaveing them on and be confident I am not going to come back to a flat battery. I can also monitor the fridge consumption better ( and feel like I am clever than I am ).

As the fridge went onboard when the clocks changed, I figure it might stay till they go back.

Annoyingly the MPPT controller has a setting to turn on the load of a night and turn off of a day, but vice versa.
So I have set the voltage so the battery doesn't fall below 12.6v

I do have space for a 3rd battery however the box is only 11" long so will not take a 100amp hour leisure battery. Leaving me with mixed batteries in the same circuit, ok but not ideal.

I have also considered mounting a second 100watt solar panel on the back of the existing panel so I have twice as much area to the sun, without tilting the panels. However I would want these removable/ adaptable so I could make use of all 400watts when I wished.

Those projects are on hold till I see how the present set up stands up.

We've got a similar setup. 39ft boat with relatively high freeboard. The panels stay in place at all times except when coming alongside, when I drop them to make it easier to do warps etc.
I initially hung mine from the guard wires directly, which was fine. I later added steel tubing but that was really to brace my bimini.
I don't have a support prop, my panels are lifted using lines from above. I already had a defunct wind turbine pole and an aerial mast in the right places. Another line pulling down to the toerail stops the wind from getting under the panels and flipping them.

My solar panels where bought because they where cheaper than custom side screens that where lower than the top rail.
We have hung solar panels on the lower guard rail.

About 1/3 of the way down using a bit of line to secure the bottom down. It can also be tied to the upper guard to angle the panels angled if required.

It works well for us.

 

[geem]

Did you always have rigid guard rails?

Or, were they originally wire, and you converted to pipe for this installation?

It looks like the panels stay in place while sailing - right?

how big is this boat?

That wire was swapped for tube on the last part of the boat so we could fit a panel between each stanchion.
Panels stay in place whilst sailing.
44ft boat.

 

[migs]

A rough estimate for the average daily energy from a solar panel can be made by dividing the panel’s nominal power output by four i.e. a 120W panel will produce about 30Ah per day (on a 12V system during a Northern Europe summer).

However, first of all minimise your fridge’s energy consumption by ensuring that:

* The fridge is well insulated

* Its condenser receives cool air from the bilge, and hot condenser air can escape easily (perhaps assisted by a computer fan?)

* Set it to the maximum safe temperature (and confirm this with a thermometer to check accuracy)

* Always keep the fridge completely defrosted

* Consider fitting a keel cooler

Then, maximise you daily solar energy production by fitting mppt charge controllers and if possible a Lithium battery.

By doing this, our fridge consumes about 24Ah per day; and at anchor a 120W solar panel easily meets our needs.