Are high wattage solar panels worth the hastle...

[George94]

Bimble sell Tracer MPPT controllers, amongst others, and these are genuine, and good value.

[nbfiresprite]

Then there is Meadotech for Victron controllers.

 

http://store.meadotech.com/#!/MPPT-solar-charge-controllers/c/13042968/offset=0&sort=normal

 

http://store.meadotech.com/#!/PWM-solar-charge-controllers/c/13042969/offset=0&sort=normal

[Paul C]

You can presently get really quie high wattage solar panels for a great price.

The trouble is that this means more amps get pulled though the solar controller and high amp solar comtrollers are expensive.

 

At what point is it worth buying a larger panel?

 

Freya

 

The question is perfectly solvable, the only issue is there's lots of missing data that you need to research/calculate/find out.

 

Firstly, how much power do you need? You need to do, or guess at, a power audit. Assuming 12V system, an answer in Ah per day should be obtainable. And you could consider this for summer and winter, if its significantly different.

 

Secondly, how much £ does it cost to generate power at the moment? If its by charging the batteries via running the engine and spinning the alternator, then its an expensive way to do it, lets say £1.50/kWh (but....work it out or properly research it....) If you're on shoreline, its likely to be much cheaper but still a cost.

 

Thirdly, appreciate that solar power generates electricity when you don't need it, more or less. You need to turn the lights on in the evening, just as the sun goes down and the panels then do (almost) nothing. And in a gloomy winter, you'll need the lights on for longer, just when the sun is weak and the solar panel's daily output is typically about 10% of summertime. If only you could have one big massive battery that charged and charged in the summertime, then took all winter to discharge.....

 

Then decide, because you're comparing a capital cost item (solar panels and controller) with a running cost item (diesel and other wear/tear on the engine), what time period you'd like to consider. Solar panels lose their efficiency, but not by much, quickly, so a 10 year span is reasonable.

 

 

 

Once you have all of the above you can put various different scenarios together to work out the cost of electricity, for example:

 

Scenario 1: summertime, no solar (ie no additional capital costs), but running costs £xxx/day or month or year etc

 

Scenario 2: 100W of solar power. You will spend a bit on capital costs but save on running costs. But bear in mind, in winter time the solar doesn't generate enough, so you need to supplement it with some engine running.

 

Scenario 3: 2000W of solar power. You spend a bit more on capital costs - not 4x as much as scenario 2, because you have some economy of scale for big panels etc. And now you can go "deeper" into autumn/winter/spring. (Will probably still need some engine running on dull days). Worth doing a bit of research and possibly working the figures out on a month-by-month basis. So running costs are even less then scenario 2. BUT in the summertime, you'll probably have an excess of power, so that capital is tied up and not benefitting you.

 

Obviously at some point in between Scenario 2 and 3 there is an optimum where the addition of more solar power doesn't reduce the overall costs to offset its capital cost. The only way to properly know that is to know the figures which determine the costs.

 

Also, as previously mentioned, you'll run out of roofspace to fit the panels on - or the addition of more and more panels is possible but inconvenient (ie lose storage/working space on the roof).

[Ukiyo]

 

4) Putting 12v directly into your battery straight from solar panels via a controller.

 

All methods of battery charging 'cost' (primarily either petrol or diesel) although plugging into the mains (landline) is without doubt the cheapest.

 

Once the initial 'capital expenditure' of the solar system ( you could get a good system from Bimble for £500 ish) has been paid the electricity is 'free'

 

The 'capital expenditure' for a generator is similar ( or higher) than Solar, and, you have the ongoing costs of (around) £1 per hour to run it.

 

We can live comfortably ( 12v Fridge on 24/7, unlimited TV, phone charging, PC charging, lighting, occasional twin-tub washing machine, water pumps etc) in the Summer with 200 watts. In fact, the SOC of the batteries ( 2 x 135Ah) when we got up in the morning was higher than when we went to bed.

We could moor up for at least 3 days without running the engine - probably longer if I really wanted to.

Just as an aside - I believe that an MPPT controller will give round 30% more 'power' than a MWP controller.

The controller may cost more, but, its worth it for the 'extra' that actually gets put into your batteries

 

I love hearing about what you are all doing with solar. It sounds incredible to me and is very inspirational!

I've been what Phil would call "camping" for about 6 months now.

 

Actually I've also been able to charge laptop and phone batteries in the library too, so that's kind of mains charging, tho I don't bring the marine battery with me

 

I'm quite limited in what I can do in my current situation, especially now it's winter and the bas***** moved the sun, but I'm thinking if I'm able to change things then I could have a much greater potential capacity and you guys seem to be backing that up although I guess some of your power is coming from the engine in addition to your panels.

 

Food for thought anyway!

[Ukiyo]

The PWM controllers aren't fake. They're the simple ones, and very cheap, and do work well for the price. It's the cheap MPPT controllers which are fake, mostly. A good MPPT controller can give up to 30% more power from the same panels.

 

If we are talking the cheap chinese ones then they are also fake. You can get cheap PWM controllers from morningstar tho and sometimes other places too. PWM stands for Pulse Width Modulation. It works by sending pulses down the wires. These pulses can be picked up with a simple FM radio, so an easy test to see if it's really PWM is to put an FM radio right on the cables and see if you can pick up the signal. It's kinda funny because they have gone to a lot of trouble to make it seem like PWM but they still fail the radio test which is easy enough to do.

 

Hope that helps!

 

The chinese controllers are still great value tho because they do work, and they are very cheap, they just arent PWM.

 

Bimble sell Tracer MPPT controllers, amongst others, and these are genuine, and good value.

 

 

George you are awesome. I will look into these.

 

I will definitely also check out the meadotech stuff. Thanks very much Firesprite!

Edited December 11, 2015 by Ukiyo

[GoodGurl]

You will get the biggest benefit and savings from your panels in summer if you don't cruise daily.

I have 1KW of solar along with 2 mppt controllers, I also run a full size 12v fridge and freezer,240v dryer and washing machine, washing is normally done when cruising but it has been known for me to be able to wash from the solar alone.

[Alan de Enfield]

I have recently bought one of these kits for our Cruiser.

 

It features a 'low light' panel which works better in our Northern latitudes where the Sun is lower in the sky. In the low winter Sun they give around 100% more output compared to conventional panels, and across a full year they will average out at 10% above 'standard' panels.

Add in the fact that you get around 30% more with an MPPT controller and you are looking at huge gains over standard panels with PWM controllers.

 

http://www.bimblesolar.com/offgrid/12v/12v-170w-cis-mounting

 

170 watt kit at £280.

 

I deleted the parts I didn't need ( mounting blocks and 'mastic stuff') so it came out even cheaper.

[Ukiyo]

That is a great post Paul. Thankyou.

 

I know my original question was a bit lacking in detail but that's because I don't go to forums to get the answer to something because with a lot of things in life there isn't one right answer anyway. However I find it useful to hear a variety of different opinions and also it's really great to hear other peoples actual experiences.

 

I'm not quite sure what my future situation is going to be like but I want to improve on the current situation at some point and have a better standard of living. As Phil implied. Living shouldn't be just camping. Having said that I like that way of looking at things.

For the time being I'm just camping!

 

Right now my system is a bit limited in the ways you guys talk about and more. I only have so much space for my panels so I've used a slightly better controller to try and help. Perhaps the obvious next step would be to get enough panels to max out the 10amp controller I already have.

Edited December 11, 2015 by Ukiyo

[MtB]

I have recently bought one of these kits for our Cruiser.

 

It features a 'low light' panel which works better in our Northern latitudes where the Sun is lower in the sky. In the low winter Sun they give around 100% more output compared to conventional panels, and across a full year they will average out at 10% above 'standard' panels.

Add in the fact that you get around 30% more with an MPPT controller and you are looking at huge gains over standard panels with PWM controllers.

 

 

I'm very concerned about this. Are you stating your empirical experience or just paraphrasing the Bimble website claims?

[Alan de Enfield]

 

 

I'm very concerned about this. Are you stating your empirical experience or just paraphrasing the Bimble website claims?

 

I have not had it installed long enough to confirm the figures - as you say they are taken from Bimbles 'blurb'

[Paul C]

PS I happily used a microwave (small one) using nothing more than 200W solar power to recharge the batteries. In the spring/summer/early autumn there was no need to run the engine to keep the batteries charged up. The thing with microwaves is, although the power requirement is high, they are not on for a long time so the energy requirement isn't massive. 2 mins microwave use, half the day available to charge the batteries etc

[Ukiyo]

PS I happily used a microwave (small one) using nothing more than 200W solar power to recharge the batteries. In the spring/summer/early autumn there was no need to run the engine to keep the batteries charged up. The thing with microwaves is, although the power requirement is high, they are not on for a long time so the energy requirement isn't massive. 2 mins microwave use, half the day available to charge the batteries etc

 

This was through an inverter?

 

I'm guessinga big part of making that work will be about batteries that are up to supplying the draw even if it is only for a short time. Would love to have a microwave tho.

 

Freya

[Paul C]

Yeah, what's more, a MSW inverter (Modified Sine Wave), not PSW (Pure Sine Wave). I think it was partly research, and partly luck, that I found a microwave that worked with a cheap MSW y with no real issues - go for one with a manual/mechanical timer, not a digital display/etc, and go for a low power one. You need to cook things for a bit longer but you'll get the knack of adding a little bit of time on.

 

The battery bank was 3x plain old cheap lead acid leisure batteries. Since this style of battery is commonly sold as a "dual purpose" start/leisure battery, and that starting currents can be typically 100+ Amps, then with the 3 of them powering the microwave its typically 80A total, so ~27A each, well within the capability of the battery. The wiring needs to be good quality, I used 50mm2 because of the distance; and items such as the fuse and isolator switch need to be correctly specified too.

[Sea Dog]

I'm very concerned about this. Are you stating your empirical experience or just paraphrasing the Bimble website claims?

Consider yourself "Bimbleblurbed"!!

[Justme]

There is a bit of a myth being started here.

 

At least two people have said that the power only comes from the battery & that you cant run items from the panels. Whilst you need the bats to stabilise the system they dont have to be providing any power.

 

The fact is that if you are using any power while the panels are producing then that power does not enter the battery but is used directly. Only after any instant loads are dealt with will the battery take its share.

 

It is always better to use the power as its is made or collected. So no charging losses,

 

Panels make 3 amps using 2 so 1 goes into bat

Panels make 3 using 5 so 2 coming from bats

Panels make 3 using none so all 3 go to the bats

[Paul C]

There is a bit of a myth being started here.

 

At least two people have said that the power only comes from the battery & that you cant run items from the panels. Whilst you need the bats to stabilise the system they dont have to be providing any power.

 

The fact is that if you are using any power while the panels are producing then that power does not enter the battery but is used directly. Only after any instant loads are dealt with will the battery take its share.

 

It is always better to use the power as its is made or collected. So no charging losses,

 

Panels make 3 amps using 2 so 1 goes into bat

Panels make 3 using 5 so 2 coming from bats

Panels make 3 using none so all 3 go to the bats

 

Simple diagram explains, substitute "engine off" for "night time"; and "alternator" for "solar panels" or more generally, "charging source"

 

[Ukiyo]

Yeah, what's more, a MSW inverter (Modified Sine Wave), not PSW (Pure Sine Wave). I think it was partly research, and partly luck, that I found a microwave that worked with a cheap MSW y with no real issues - go for one with a manual/mechanical timer, not a digital display/etc, and go for a low power one. You need to cook things for a bit longer but you'll get the knack of adding a little bit of time on.

 

The battery bank was 3x plain old cheap lead acid leisure batteries. Since this style of battery is commonly sold as a "dual purpose" start/leisure battery, and that starting currents can be typically 100+ Amps, then with the 3 of them powering the microwave its typically 80A total, so ~27A each, well within the capability of the battery. The wiring needs to be good quality, I used 50mm2 because of the distance; and items such as the fuse and isolator switch need to be correctly specified too.

 

 

Thanks for the info Paul!

I've been a bit off the map so sorry for the slow reply.

Not sure I'm going to get one as it seems like a fabulous indulgence but I'd like to know the make and model of microwave if you remember.

 

Who knows I might get one (I'm worth it!)

Edited December 20, 2015 by Ukiyo

[Paul C]

It was the cheapest one from Asda with a mechanical timer, they've probably changed it now anyway......

 

I don't see a microwave as an indulgence, I'd say 99% of homes have one after all....so why not on a boat.

[Alan de Enfield]

We have a 600w 'mechanical' timer microwave ( above the top oven) It takes about 60 amps ( a bit more on start-up) out of the batteries but as its only on for (maybe) 3 minutes to heat a tin of beans its only an absolute minimum of maybe 3Ah out of the batteries.

 

Electricity is virtually a 'no-cost' option as you get it for 'free' when running the engine (cruising) anyway, or the solar panels replace it. To use gas costs money.

 

If your system is geared up to 'work' with the appliances you want then you don't have to live in the stone-age

 

Edit to Add ;

1) The microwave works very happily with a Sterling "Quasi" (Modified) Sine Wave Inverter.

2) The 'electrically thirsty' fridge (in the photo) has been replaced by a Waeco 35-40Ah / day 12v fridge

3) The new freezer is an Argos 220 volt using roughly 400 watts per day ( 40 Ah from the batteries)

4) The electric kettle is 1000w

5) The Immersion heater is 1000 watts

6) We have 880Ah domestic battery bank

 

Edited December 20, 2015 by Alan de Enfield

[WotEver]

If your system is geared up to 'work' with the appliances you want then you don't have to live in the stone-age

 

Or as others sometimes put it "Boating isn't camping"

[Ukiyo]

Thanks for the photo Alan. That really does have a lot of style in a nice compact space!

Very impressed.

 

So the microwave is a bush. Do you know what model it is?

Perhaps you just need to find a microwave with the good old analogue controls for it to work with a modified sinewave inverter.

[Alan de Enfield]

Thanks for the photo Alan. That really does have a lot of style in a nice compact space!

Very impressed.

 

So the microwave is a bush. Do you know what model it is?

Perhaps you just need to find a microwave with the good old analogue controls for it to work with a modified sinewave inverter.

 

I think it is a Bush BM997.

But any small ( wattage) microwave that is not reliant on electronics (ie mechanical knobs) should work on a MSW Inverter. You may need a Full PSW inverter for an 'electronic' microwave.

 

Here is a 'mechanical' one from Tesco - for the sake of £40 its got to be worth a try.

http://www.tesco.com/direct/tesco-solo-microwave-mmbs14-17l-black-and-silver/287-0474.prd?skuId=287-0474&pageLevel=sku&sc_cmp=ppc_sh-_-sh-_-tesco-_-287-0474&gclid=Cj0KEQiAwNmzBRCaw9uR3dGt950BEiQAnbK96-d_JOvGPedmkclx7ku9V6Ja5EXfWlHF_TyrfCuR4fEaAoxp8P8HAQ&gclsrc=aw.ds

[peterboat]

good evening freya, i have had solar panels for the last ten years. my present boat has just under 900 watts and a 1500ah battery bank, i have a automatic washing machine, dishwasher, microwave, kettle etc etc.

summertime i have all the power i need but wintertime i run my wispergen for 3 hours a day it creates 72 amps at 12 volt and runs the central heating as a perk.

in the winter i am much more frugal with power as its costly to produce but the rayburn royal is on 24/7 so hot water and cooking is taken care of.

i decided early on i did not want to camp on my boat so this my second boat planned to be comfortable

 

good luck freya on your solar adventure