Jump to content

solar panels


trundler

Featured Posts

Hello ,

 

We have moved up from a 45ft nb to a 60ft nb. We have a winter mooring with electric hook up, so we are looking at solar panels for the summer months.

 

We are looking at 2 x 165w panels with mppt regulator.

 

Do the more experienced folks think this will give us enough power to NOT have to keep running the engine, please.

 

I run the washing machine when we are cruising, so typically, when moored up, we have TV, Laptop,radio. Lights are all led. We also inherited an old 12v fridge, which is still just about working. We charge up2 phones and 2 kindles.

 

Thanking you in advance for any info.

 

 

Jenny.

Link to comment
Share on other sites

We have 440w and from May till end of summer they cover our electrical needs.

We have an inverter which has a very low power sleep mode that powers the fridge, a 240v A++ model.

We also have LED lights and our tv is just 20W and a bit of lap top use.

We have 660Ah of battery capacity so can easily cope with the odd cloudy day.

 

In summer the batteries are full by lunch time, so if you are reasonably modest users of power, than I would think you will be fine for all the summer.

 

We do run the engine for hot water, which also makes electric power, which we don't need with the solar, but as we move a bit most days it is not an issue for us.

Edited by Chewbacka
Link to comment
Share on other sites

200w of solar and a 220ah bank covers our needs from late April to September. We have a 12v shoreline fridge, LED lights, pumps , mobile phones and use the TV from a cheap MSW inverter. Fitting a Victron MPPT controller instead of the Chinese PWM made a huge difference!

Link to comment
Share on other sites

Should be ok just make sure you have enough good batteries to store the electric in

What he said. Having decent batteries is just as important. I have 500w of solar but 3 x 100ah batteries which probably want replacing. I'm fine for power at the moment but the batteries don't hold charge as well as the did. If I was going to spend more money, it would be on improving my battery storage since on a sunny day I can put 100s of amps in my batteries but have no way to store it all for a miserable, wet, overcast day.

Link to comment
Share on other sites

This has opened up my old "Can of Worms" again. I have 400wts Solar, and 440amp batteries. Before anyone says so, I have no dead or dying batteries as I rotate them and keep one spare monitoring its discharge rate. ie 12.9v in Feb still at 12.6 today.

 

And yet, I am struggling on most normal cloudy days to maintain my meagre requirements, ie. TV Leds amd laptop. The thought ( like most of you do ) of successfully running any sort of fridge just eludes me.

 

I'm at Crick for 2 weeks if anyone could shed more light on this for me.

Link to comment
Share on other sites

This has opened up my old "Can of Worms" again. I have 400wts Solar, and 440amp batteries. Before anyone says so, I have no dead or dying batteries as I rotate them and keep one spare monitoring its discharge rate. ie 12.9v in Feb still at 12.6 today.

 

And yet, I am struggling on most normal cloudy days to maintain my meagre requirements, ie. TV Leds amd laptop. The thought ( like most of you do ) of successfully running any sort of fridge just eludes me.

 

I'm at Crick for 2 weeks if anyone could shed more light on this for me.

I'm at the Crick Show on the Monday. I could come by? Have you tried cleaning your panels? How long is your TV / laptop on for? What is your controller? What thickness are your cables? Has it always been like this? What kind of charging figures are you getting? How old are you panels?

Edited by Dave_P
Link to comment
Share on other sites

This has opened up my old "Can of Worms" again. I have 400wts Solar, and 440amp batteries. Before anyone says so, I have no dead or dying batteries as I rotate them and keep one spare monitoring its discharge rate. ie 12.9v in Feb still at 12.6 today.

 

And yet, I am struggling on most normal cloudy days to maintain my meagre requirements, ie. TV Leds amd laptop. The thought ( like most of you do ) of successfully running any sort of fridge just eludes me.

 

I'm at Crick for 2 weeks if anyone could shed more light on this for me.

You say the batts are ok at holding a voltage but does that also mean your supposed capacity of 440 amp hrs is still that. I think it maybe it's much less. Just for example I have 675 amp hrs with 235 w of solar but running TV,sky box, fridge, microwave, led lights, pumps and charging two phones two iPads can normally be achieved without running engine for two days sometimes three. Someone more expert will be along but I think you may have a capacity issue.

Link to comment
Share on other sites

Note what Phil said.

 

How do you test/measure your battery capacity?

 

If they are open cell batteries compare the specific gravity indication of state of charge with that given by the rested off load voltage. The greater the difference between the two readings the more sulphated the battery is.

 

If they are closed cell then all you can do is fully charge them and then discharge with a known load to about 11 volts (try to choose a load that will do it in around 20 hours. Then the time taken multiplied by the load current will give you some idea about the capacity.

 

Have you tested for any current flow when everything is turned off?

 

 

Link to comment
Share on other sites

This has opened up my old "Can of Worms" again. I have 400wts Solar, and 440amp batteries. Before anyone says so, I have no dead or dying batteries as I rotate them and keep one spare monitoring its discharge rate. ie 12.9v in Feb still at 12.6 today.

 

And yet, I am struggling on most normal cloudy days to maintain my meagre requirements, ie. TV Leds amd laptop. The thought ( like most of you do ) of successfully running any sort of fridge just eludes me.

 

I'm at Crick for 2 weeks if anyone could shed more light on this for me.

like others I would suggest that your batteries are failing

 

by monitoring a standing batteries voltage all you are doing it working out it's self-discharge rate not it's capacity.

 

my battery bank is 330ah (and is just under a year old and has never been abused etc etc)

140w of solar was fitted at the same time as the battery bank.

 

my usual loads are

fridge (10A when running, thanks to a faulty door seal that is near 50% of the time) so average load of 5A ---- 24 x 5 = 120AH)

Lights (roughly 2A when in use, usually 4 hours) --- 4 x 2 = 8AH

TV 1.5A for around 2 hours --- 2 x 1.5 = 3AH

pumps intermittent use estimated at 1AH

various chargers estimated at 5AH

 

rough total daily usage 137AH

 

solar can produce 140w (on paper) multiply by 0.75 for something nearer uk output (105w or 8.75A @12v)

137AH divided by 8.75 shows that I would need 15 hours of solar output per day to fully recharge my batteries which for most of the year will not happen, therefore on paper I can go a few days before having to find some other way of adding power to the batteries

 

in practice either my usage figures above are over estimated or solar output is underestimated since I tend to find that by about 2pm at this time of year the solar has fully charged the batteries and shut down

Link to comment
Share on other sites

I am sat now looking at my BM2 showing 27 amps from my panels 14.1 volts at the batteries. I have a 1500 ah battery bank.

I use electric as I need it and never worry about it as I have 900 watts of solar. If I was a constant cruiser I could get away with half the battery bank and half the panels, what I am saying is look at what you need and then add some on for dull days

Link to comment
Share on other sites

  • 3 weeks later...

I am also looking for some advice around solar. I was at Crick and spoke to several of the solar panel suppliers there, but sales people of course always tell you that their option is best.

 

First question is: rigid or flexible panels? Flexible is so much more attractive as it ... well ... lies flat and you can walk over it. These here were touted as the best of the best, because they are "micropitted" to absorb sunlight at every angle so no need to angle panels toward the sun:

http://www.photonicuniverse.com/en/catalog/list/category/flex-panels

Sounds quite convincing, but they are more expensive.

 

IF rigid panels are better, then next question is, is it worth tilting them? The vendors I spoke to called it a "gimmick", not worth it. Again you can walk over a flat mounted panel but not a tiltable one. But I read an article that explained that you get so much more out of the tilting. The correct tilting of the panels seems quite a science though (or more an art?).

 

I am looking for enough solar power to supply the summer months using a 12V fridge and TV, several gadget chargers (computer, phone, ipad, wifi mainly) and LED lighting. From what I read here it sounds like one 250w should do it? That was the biggest they offered generally. I wouldn't want two panels if it can be avoided.

Edited by Lizzy
Link to comment
Share on other sites

Personally I would be less inclined to think that flexible panels will not de-laminate. There were a lot of reports about this a few years ago.

 

If anyone told me it was a waste of time tilting the panels I would not use them. Have a look at any solar farm - do you see any horizontal panels? having said that as a cruising boat mine are horizontal but if a livaboard they would tilt as required.

 

Before spending hard earned money with "marine" places that exhibit at Crick please look at Bimble Solar's website.

 

 

PS please do not try to walk on a rigid panel, it will almost certainly break because they are usually fitted clear of the roof. this helps them stay cooler and make more electricity.

Edited by Tony Brooks
Link to comment
Share on other sites

Flexible are fine provided you can prevent moisture getting behind the panel or it will over time damage your paint and or rust the roof. Rigid, this problem is avoided and tilting is better than laying flat but the tilting brackets look hideous. You will probably need more than 250 w in reality nearer 400 w for all you want to run. Look at the performance of the panels not just the wattage. Some panels are only 18% efficient whereas others are 21% or more. If you only want one panel look at LG or even better Panasonic HIT. LG do single panels at 330 w now but they are not as efficient as the Panasonic ones so you would have the weigh up the differences. There is a panel that absorbs light from both sides but the required gap underneath is too big I think. Just as important as the panel get a decent mppt charge controller. Finally don't walk on rigid panels they will break.

Edited by Phil.
Link to comment
Share on other sites

I am also looking for some advice around solar. I was at Crick and spoke to several of the solar panel suppliers there, but sales people of course always tell you that their option is best.

 

First question is: rigid or flexible panels? Flexible is so much more attractive as it ... well ... lies flat and you can walk over it. These here were touted as the best of the best, because they are "micropitted" to absorb sunlight at every angle so no need to angle panels toward the sun:

http://www.photonicuniverse.com/en/catalog/list/category/flex-panels

Sounds quite convincing, but they are more expensive.

 

IF rigid panels are better, then next question is, is it worth tilting them? The vendors I spoke to called it a "gimmick", not worth it. Again you can walk over a flat mounted panel but not a tiltable one. But I read an article that explained that you get so much more out of the tilting. The correct tilting of the panels seems quite a science though (or more an art?).

 

I am looking for enough solar power to supply the summer months using a 12V fridge and TV, several gadget chargers (computer, phone, ipad, wifi mainly) and LED lighting. From what I read here it sounds like one 250w should do it? That was the biggest they offered generally. I wouldn't want two panels if it can be avoided.

Tilting panels will maximise the output, basically the panel needs to be at right angles to the sun.

However this also means that to get the most output you would also rotate the panels to keep it pointing at the sun as it moves across the sky.

In the summer I have more than enough panels to cover our needs (400w) and they work fine just flat.

However in the months when the sun is low down in the sky I do not get a lot and then tilting and rotating would make much more of an improvement.

250w might be enough, but it sounds a bit low to me - all depends on how long you watch TV for, how often you open the fridge etc

Link to comment
Share on other sites

I am also looking for some advice around solar. I was at Crick and spoke to several of the solar panel suppliers there, but sales people of course always tell you that their option is best.

 

First question is: rigid or flexible panels? Flexible is so much more attractive as it ... well ... lies flat and you can walk over it. These here were touted as the best of the best, because they are "micropitted" to absorb sunlight at every angle so no need to angle panels toward the sun:

http://www.photonicuniverse.com/en/catalog/list/category/flex-panels

Sounds quite convincing, but they are more expensive.

 

IF rigid panels are better, then next question is, is it worth tilting them? The vendors I spoke to called it a "gimmick", not worth it. Again you can walk over a flat mounted panel but not a tiltable one. But I read an article that explained that you get so much more out of the tilting. The correct tilting of the panels seems quite a science though (or more an art?).

 

I am looking for enough solar power to supply the summer months using a 12V fridge and TV, several gadget chargers (computer, phone, ipad, wifi mainly) and LED lighting. From what I read here it sounds like one 250w should do it? That was the biggest they offered generally. I wouldn't want two panels if it can be avoided.

 

I'm also looking at the 250watt semi flexible panel from photonicuniverse, the reason been is I'm aiming to have two on the wheelhouse roof and the size and weight is nearly perfect.

 

I'm not keen on framed panels that can tilt as I don't want to spoil the look of the boat and make it look like a solar panel farm.

Link to comment
Share on other sites

Tilting solar panels on a boat -- especially if they can only tilt laterally -- has less output impact than you'd expect, because it also depends which way your boat is pointing -- if the mooring is N/S then it doesn't help at all. You'd get similar average output using flat panels and increasing the size by maybe 20%, and not have to worry about all the tilting hardware.

Link to comment
Share on other sites

If anyone told me it was a waste of time tilting the panels I would not use them. Have a look at any solar farm - do you see any horizontal panels? having said that as a cruising boat mine are horizontal but if a livaboard they would tilt as required.

 

 

But Sir, SIR, the primary reason for panels on solar farms being tilted is so they get cleaned by the rain, rather than to optimise the output.

 

Far cheaper to install them flat but the accumulating dirt will eventually stop them working.

 

Bear in mind they are permanently tilted in one direction which at some times of day improves output, at other times of day harms it. They don't turn to follow the sun.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.