OK ... request for dimensions of Solar Panels

[Refueler]

Hi Nigel I understand your question and uncertainty. I have been looking at new PV panels for household roof top. The latest panels appear to be of similar size to my 10 year old panels but seem to be claimed twice or more the wattage. Now I understand there have been huge improvements in PV efficiency over that time. I perceive that you want a flexible panel for new boat. Would you be getting latest technology? Would be interesting to see area versus watts of what is available and compare that to claims for large PV panels for domestic use. Actual watts delivered by my inverter with so called 1500w array is at best around 1200 watts summer midday. (at 32 S)
Anyway good luck with your quest and I hope to see what you find. ol'will

I have connection with industrial / domestic Solar installations - but that info is actually little use in this topic ... the scales are way out of proportion.... and the panels are aligned 24/7 to best direction ... unlike a boat !

So far various replies have gone the route I was trying to steer clear of ... looks like I shall go back to my online searches with fingers crossed that I get what I am looking for.

To those who push brand names ..... a large % of panels are made up of cells / batches made in China ... various brands state "made in Germany' etc. - that's assembled ... the cells generally are not. I know this as fact as China is a market I have been in for many years ... as some others have been on this forum ...

My goal is to have a system that is economical on space needed to mount panel - hopefully in same place replacing the old. To maintain the 3 Lead Acid batts (each of 75A/hr) ... 2 are domestic .. 3rd is engine. Plus the compressor fridge I have ... I assume at most maybe 6A or more when first cooling down ....
I am aiming I suspect at about 250 - 300W overall ... with a minimum of 100 - 150W if size is a limitation.

 

[fredrussell]

We’re not pushing “brand names” so much as reputable suppliers. Give em a call. Reputations are earned.

 

[B27]

I have connection with industrial / domestic Solar installations - but that info is actually little use in this topic ... the scales are way out of proportion.... and the panels are aligned 24/7 to best direction ... unlike a boat !

So far various replies have gone the route I was trying to steer clear of ... looks like I shall go back to my online searches with fingers crossed that I get what I am looking for.

To those who push brand names ..... a large % of panels are made up of cells / batches made in China ... various brands state "made in Germany' etc. - that's assembled ... the cells generally are not. I know this as fact as China is a market I have been in for many years ... as some others have been on this forum ...

My goal is to have a system that is economical on space needed to mount panel - hopefully in same place replacing the old. To maintain the 3 Lead Acid batts (each of 75A/hr) ... 2 are domestic .. 3rd is engine. Plus the compressor fridge I have ... I assume at most maybe 6A or more when first cooling down ....
I am aiming I suspect at about 250 - 300W overall ... with a minimum of 100 - 150W if size is a limitation.

It's not clear from what you're saying, are you looking to 'maintain the batteries' or run a fridge 24/7?

Maintaining a few lead acid batteries is no problem, typical float current is a few tens of milliamps, a few Ah per week. A small panel can do that if it sees a few hours of full sun per week or the equivalent of.

Running an efficient fridge on sunny days is easy. I have a fridge which averages less than an amp and a 50W solar panel. If the weather isn't very sunny, then some of the Ah start to come from the alternator.

As we get more into Autumn, then if I run the fridge for two days, the solar panel may take a week to fully recharge the battery.

The yield from my 50W panel can be 20Ah for a hit sunny day. On a rainy day in Autumn it might make 1Ah.

Not only does the sun shine less, but it's lower in the sky and shading from the trees and hills reduces the opportunity for the panel to be in sun.

So, if I want to run a fridge or the heater much in Autumn, I need to either rely more on the alternator, accept that the solar might take a long time to recharge the battery, or fit much more solar. Or I might get a Lithium battery of some sort which I can take home to charge.


You can always buy more panels and increase the number of days when solar will meet your needs, but in UK latitudes you will need a lot of panels to run significant loads 52 weeks of the year.


Everybody will have an individual judgement of how far to go down the 'more panels' road.
A starting point for that judgement is a clear view of your needs in Ah and what % of days in which months you want the solar to deliver that.

 

[Gatewaysailing]

can you provide the links to the items if they still in stock please?

 

[Refueler]

can you provide the links to the items if they still in stock please?

Who are you asking ??

 

[Gatewaysailing]

We used Craig Solar.

2X 200W rigid panels, each 100cmx100cm. EPever 30AMP controller.

Mounted on the pilothouse roof, only slight shadowing from the twin backstays or boom under some conditions.

Since fitting 12th May '22, when aboard we run two large refrigerators and a Dometic 40 litre freezer box 24/7.

Batteries not been charged except by main engine alternator or the solar since that date.

Even on dull days batteries reach float. Four or five consecutive dull or rainy days they drop to 12,7-12.8V. Lower if we use the inverter for cooking.

Well pleased, I got EXACTLY what I hoped for.

Monocrystaline rigids is the way to go IMHO.

can you provide the links if they still in stock?

 

[Pete7]

can you provide the links if they still in stock?

CraigSolar | eBay Stores

 

[Baggywrinkle]

I have connection with industrial / domestic Solar installations - but that info is actually little use in this topic ... the scales are way out of proportion.... and the panels are aligned 24/7 to best direction ... unlike a boat !

So far various replies have gone the route I was trying to steer clear of ... looks like I shall go back to my online searches with fingers crossed that I get what I am looking for.

To those who push brand names ..... a large % of panels are made up of cells / batches made in China ... various brands state "made in Germany' etc. - that's assembled ... the cells generally are not. I know this as fact as China is a market I have been in for many years ... as some others have been on this forum ...

My goal is to have a system that is economical on space needed to mount panel - hopefully in same place replacing the old. To maintain the 3 Lead Acid batts (each of 75A/hr) ... 2 are domestic .. 3rd is engine. Plus the compressor fridge I have ... I assume at most maybe 6A or more when first cooling down ....
I am aiming I suspect at about 250 - 300W overall ... with a minimum of 100 - 150W if size is a limitation.

Got one of these from Amazon ... Amazon.co.uk


... and used it to measure any loads where the details weren't written on the device


Transferred the values to Excel and did a load calculation for a day sitting at anchor ...



... and worked out I need 0,9kWh a day or thereabouts (Bav36 with standard compressor fridge)

I then sized my AGMs so that 0,9kWh was about 25% of capacity (to avoid deep cycling my batteries regularly) and ended up with 370Ah due to my availability/price/quality assessment.

Then looked here ... MPPT Calculator - Victron Energy .... to find out what kind of yield I could expect at my location using the details of my proposed system.

Pula in the Adriatic came out like this for a 300W array ...



Which happily covered my requirements for my cruising season and kept the batteries topped up over winter when the fridge was off.

Bought the bits, fitted it and it worked as predicted.

Could sit at anchor indefinitely with the fridge running 24/7 ... and I was never short of a cold beer or two.

 

[Refueler]

The Wattmeter you show is same as we use for Model Lipo / LifePo / NimH / Lead acid etc for determining motor / esc / battery compatibility ... we can be pulling anything from just a few amps to 100 - 150A .....

I was planning to do similar on my boats to create a graph of consumption vs input.

The only difference with mine as example ... is usual Wattmeters we use have various modes to select :

 

[Supertramp]

I have a 130w panel, Sunshine Solar. It will provide float current on a poor day. On a sunny day it provides 5-7 amps which is enough to power instruments and autopilot on passage, or fridge at anchor. As others have said angle and shading significantly reduce output from the maximum. I installed it to charge batteries on passage and at anchor. I coastal cruise, not liveaboard.

I chose the panel for its size, and the rounded corner mounts to avoid damage to me or ropes. Below is a Smart Victron MPPT controller with capacity for another panel and lots of history data via Bluetooth.

On a previous boat I had a small, flexible deck panel which was occasionally walked on. It was still going after 20 years. Much depends on how much you are prepared to let panels intrude on your boat and how much power you really need between engine charging. Shame to add excess clutter unless you really need it.

 

[Gatewaysailing]

good information guys , thanks