Wind Generators or Solar on Motorboat

[Greg2]

I spend a lot of time in the marina so may be looking at around £100 to £130 a month for electricity, with current rises, so I'm considering alternatives which are better longer term options.

That sounds like a lot of electricity. We have virtually everything on 12v so only run the battery charger, electric kettle and SWMBO‘s hair dryer on shore power when aboard and don’t use anything like that even accounting for current price hikes. That said, we never leave the fridges on when we leave the boat during the week. Perhaps I need to check what is happening with prices in our marina!

 

[V1701]

If you're spending that much on leccy can we assume you use it for cooling (i.e. fridge), heating & dehumidifying? I live aboard FT & in winter use about £20/week at current prices. That's running a mains fridge, electric heating (oil radiator & electric blanket) & a dessicant dehumidifier. Switching to a diesel heater would make a big difference to your leccy spend but that in turn depends how much diesel is going to go up! Either way if you're on board a lot in Winter/colder times of the year, wind and/or solar are not enough to provide you with enough power to provide heat for the boat...

 

[Fire99]

Thanks guys for the comments.. Just to clarify my electricity is around the 60 quid a month mark when I live onboard. That is likely to go up by about 50 % in the next month or so (allegedly). Being a fairly sizeable motorboat I do have a few creature comforts. So I have a 240v water heater which I do take the odd shower onboard. (A serious luxury for me after my last boat) , I have a 4 ring induction hob plus electric oven with built in microwave, all running from 240v. Plus I have a washer dryer too but I only use the wash and use the marina tumble dryers. Plus the usual TV and sockets for laptop charging. My other luxury is I have an electric blanket which I used for a couple of weeks during particularly cold weather . Heating now is all diesel heating so the electric fan for that is from the 12v.. And I do have two electric towel rails which I use to keep a little warmth in the heads.. And 1 240v heater in the engine room on minimum to stop any frost..

Sorry that ended up a bit of a list of all my electrical gear but I hope it paints the picture.. Actually today the penny kinda dropped because my only real 12v stuff when not underway is lighting (all now very low watt LED), electric fresh water pump + macerator and the fan for the diesel heater. The fridge is auto switching so is 240v most of the time until the power is cut. (I need to check the rating) so other than the fridge, not a whole lot. I guess a couple of bigsolar panels or a cheapish wind turbine would be useful for anchoring and keeping the batteries topped up, or has already been said to keep the batteries charged away from the shore power when I'm not on the boat, but nothing is going to make a serious dent in a shore power electric bill due to lots of 'home comfort' 240v devices..

That is unless I start pushing towards appliances etc that don't run on the 240v. I'm just thinking out loud here since energy prices are really cooking (excuse the pun) so I'd like to explore technology that can reduce the shoreside dependence.

 

[colhel]

Good luck running a fridge. They are the largest consumers of electric on most boats ( I have three ..!). Not only that but - captain obvious here - they run 24 hours a day. Solar will slow the drain but I believe no more than that.

There's a good chance our fridge is a lot smaller than yours, we've got less sunshine and the fridge won't have to work as hard ?. But yes a solar panel does keep the batteries going for a bit longer. Also worth taking into account how long you run the engine(s) for when considering cost savings on shore power.
Last year our main cruise was two weeks away and didn't use shore power at all due to the alternator keeping the batteries topped up.

 

[Fire99]

There's a good chance our fridge is a lot smaller than yours, we've got less sunshine and the fridge won't have to work as hard ?. But yes a solar panel does keep the batteries going for a bit longer. Also worth taking into account how long you run the engine(s) for when considering cost savings on shore power.
Last year our main cruise was two weeks away and didn't use shore power at all due to the alternator keeping the batteries topped up.

I'll have to check out the figures for my fridge. It's a single height but 1 1/2 width so a decent size.

Another thing that popped into my head, are any of you guys using 12v TV's? They seem to go up to around 32" these days and though for some TV is sacrilege when off at anchor somewhere, it's nice to have. How are they looking power wise these days?

 

[Greg2]

Another thing that popped into my head, are any of you guys using 12v TV's? They seem to go up to around 32" these days and though for some TV is sacrilege when off at anchor somewhere, it's nice to have. How are they looking power wise these days?

Yes, we have a Majestic 12v TV. When researching what to get it was clear that you can get something less expensive than these and I think some have even taken standard TV’s and wired directly to the 12v as some have a transformer to convert 240v to 12v anyway. We were persuaded by the low power consumption and ease of re-tuning and since we bought ours a year or two ago they have added a smart TV to the range. We are happy with ours - usual small TV average sound but we could wire to external speakers but just haven’t bothered.

 

[Fire99]

Yes, we have a Majestic 12v TV. When researching what to get it was clear that you can get something less expensive than these and I think some have even taken standard TV’s and wired directly to the 12v as some have a transformer to convert 240v to 12v anyway. We were persuaded by the low power consumption and ease of re-tuning and since we bought ours a year or two ago they have added a smart TV to the range. We are happy with ours - usual small TV average sound but we could wire to external speakers but just haven’t bothered.

Thanks Greg.. I'll have a look at the Majestic range.. I just want to avoid inverters and unnecessary use of the generator so if the TV is on 12v that's another nicety when away from the marina.

 

[Rappey]

Cello/ferguson do a range of 12v smart tvs . They are quite popular. The 24" is 21w.

 

[Fire99]

Cello/ferguson do a range of 12v smart tvs . They are quite popular. The 24" is 21w.

Thanks Rappey.. I've seen these on Amazon.. They don't look awful money. I'll take a look.
I think I may have a 'cunning' plan (as Baldrick would say). I think I'm going to look at fitting a couple of decent sized solar panels on the Sundeck roof, since it's space that really does very little and also pick up a second hand wind generator, nothing too fancy, that I can rig removably up top. I think they should be sufficient to minimise battery drain when away from the marina, when using LED lighting, a 12v TV and the fridge. I like a Macgyver project or two..

 

[Rappey]

Mistroma brought up a good point I failed to take in , your power needs are quite high. I'm not sure solar and wind will make much of a dent ?

 

[Mistroma]

Thanks Rappey.. I've seen these on Amazon.. They don't look awful money. I'll take a look.
I think I may have a 'cunning' plan (as Baldrick would say). I think I'm going to look at fitting a couple of decent sized solar panels on the Sundeck roof, since it's space that really does very little and also pick up a second hand wind generator, nothing too fancy, that I can rig removably up top. I think they should be sufficient to minimise battery drain when away from the marina, when using LED lighting, a 12v TV and the fridge. I like a Macgyver project or two..

I recorded the daily output from my Rutland 913 for several years in Scotland, France, Spain and Portugal.
It usually averaged about 10Ah/day over the summer season (about 10 in Scotland and 7-8 as I went further South).

That would run my fridge on 100% for about 1.5 hours or 6 hours on 25% duty cycle. A larger wind-gen would be better and simply scaling up by the swept area will give a good idea of relative performance. Expect a very small number of days with really good output and an awful lot with virtually no output at all. I did once get 140Ah over a 24 hour period when anchored off low lying ground in a gale. I had a lot of 0-2Ah/days and the average still ended up at 10Ah/day.

Solar was much more reliable. Just to give you a rough idea of output from a wind-gen vs. solar in your area.

During May and June, a 25W solar panel would give the same average output as my Rutland 913. I'd need a 60W panel in April and September to achieve the same output.

Approx. daily output from an unshaded 100W panel lying flat somewhere near Belfast:

Month ............... Wh/day ............... Ah/day
April................... 320 ....................... 25
May.................... 400 ....................... 32
June................... 400 ....................... 32
July.................... 370 ........................ 29
August............. 310 ........................ 25
September..... 200 ....................... 16

I've round the figures but they are good enough to give you an idea. Just look at the space you have, how many panels can fit and use my table to scale vs. output for panels you will buy. You will find that £150 is far better spent on solar. Buy solar first and only fit a wind-gen if all available space is covered in panels. You must then find somewhere where a wind-gen won't shade the panels and is also well above and superstructure and out of reach from a raised hand.

 

[Fire99]

I recorded the daily output from my Rutland 913 for several years in Scotland, France, Spain and Portugal.
It usually averaged about 10Ah/day over the summer season (about 10 in Scotland and 7-8 as I went further South).

That would run my fridge on 100% for about 1.5 hours or 6 hours on 25% duty cycle. A larger wind-gen would be better and simply scaling up by the swept area will give a good idea of relative performance. Expect a very small number of days with really good output and an awful lot with virtually no output at all. I did once get 140Ah over a 24 hour period when anchored off low lying ground in a gale. I had a lot of 0-2Ah/days and the average still ended up at 10Ah/day.

Solar was much more reliable. Just to give you a rough idea of output from a wind-gen vs. solar in your area.

During May and June, a 25W solar panel would give the same average output as my Rutland 913. I'd need a 60W panel in April and September to achieve the same output.

Approx. daily output from an unshaded 100W panel lying flat somewhere near Belfast:

Month ............... Wh/day ............... Ah/day
April................... 320 ....................... 25
May.................... 400 ....................... 32
June................... 400 ....................... 32
July.................... 370 ........................ 29
August............. 310 ........................ 25
September..... 200 ....................... 16

I've round the figures but they are good enough to give you an idea. Just look at the space you have, how many panels can fit and use my table to scale vs. output for panels you will buy. You will find that £150 is far better spent on solar. Buy solar first and only fit a wind-gen if all available space is covered in panels. You must then find somewhere where a wind-gen won't shade the panels and is also well above and superstructure and out of reach from a raised hand.

Good man... That's a whole lot of info there.. I've plenty of space for solar panels and they're not a fortune these days so I think I'll have a dabble with them and see how I get on.. I'll be back on the boat in the next couple of days so I'll have a good measure up and see what can fit up on the sundeck without too much fuss..

Thanks again for such comprehensive info.

 

[Hurricane]

I was away when I posted above - back home now so some more info.

We have, effectively, three fridges on board which, as Jrudge says, are the biggest concern whilst away from shore power.
I reckon that the background power consumption of the boat is about 5 Kw hours per day.
On a good summers day in the Med at anchor (and allowing for the boat swinging around the anchor), I reckon that the solar panels will harvest about 3 Kw hours per day.
Instantaneous figures are often meaningless.

I fitted a Victron MPPT controller which uses a bluetooth adaptor to produce information like this:-



The solar panels are installed on the flybridge eyebrow (that what I call it)



They are the semi rigid variety. Flexible but mounted on a GRP backing sheet.
Unlike the cheap pure stick on ones that don't last.



A yachtie friend has both solar and a windmill.
He reckons that the solar is way more effective than the wind generator.

Hope that helps

 

[stuartwineberg]

Cello/ferguson do a range of 12v smart tvs . They are quite popular. The 24" is 21w.

Factor in a cheap dc to dc converter. They don’t like the 13v plus straight off the batteries

 

[Fire99]

I was away when I posted above - back home now so some more info.

We have, effectively, three fridges on board which, as Jrudge says, are the biggest concern whilst away from shore power.
I reckon that the background power consumption of the boat is about 5 Kw hours per day.
On a good summers day in the Med at anchor (and allowing for the boat swinging around the anchor), I reckon that the solar panels will harvest about 3 Kw hours per day.
Instantaneous figures are often meaningless.

I fitted a Victron MPPT controller which uses a bluetooth adaptor to produce information like this:-

View attachment 131327

The solar panels are installed on the flybridge eyebrow (that what I call it)

View attachment 131328

They are the semi rigid variety. Flexible but mounted on a GRP backing sheet.
Unlike the cheap pure stick on ones that don't last.

View attachment 131329

A yachtie friend has both solar and a windmill.
He reckons that the solar is way more effective than the wind generator.

Hope that helps

Thanks for all the info. The app looks pretty handy for monitoring what's going on. I'm certainly swayed more towards the solar school of motoring right now. I'm going to size the sundeck up and see what will fit and see what I can source. Should be a nice little project for the summer..