Solar Power a few appliances

mishkin

Hi all,

I'm considering renovating an old family cottage this summer, it's in a very remote location and the only feasible way to do it is to actually move in during the work, the cottage is dry as a bone & in decent shape, so I'm ok there. My problem is the Electricity isn't hooked up and I work from home which requires the use of a laptop.

I plan in the future to invest in solar/wind to power the house, but at the moment I'd be happy with a (cheap) solution that will power my laptop and maybe a light. I'm thinking solar is the way to go, but honestly I'm a bit clueless on this..I'd appreciate any pointers...

quentingargan

You might as well put the solar on the roof while you're at it. You can put some or all of the panels to a charge controller and into a battery pack, then use an inverter to convert that into power. You might also want to use power tools without a petrol generator. So think about what the maximum load would be, and what the total daily requirement including lights would be. It might be possible to use hardware that later could be used to provide power during power cuts to freezers and other essential appliances if your grid is vulnerable to storm damage. If you PM me the info, I could size a system for you.

mishkin

Thanks quentingargan, that's kinda the way I was thinking, putting them on the roof now and be done with it. I'll put the info together regarding loads etc and pm you with it. Thanks a million.

12V 2.7kWh




24V 5.4kWh

Calahonda52

mishkin wrote: »

Hi all,

I'm considering renovating an old family cottage this summer, it's in a very remote location and the only feasible way to do it is to actually move in during the work, the cottage is dry as a bone & in decent shape, so I'm ok there. My problem is the Electricity isn't hooked up and I work from home which requires the use of a laptop.

I plan in the future to invest in solar/wind to power the house, but at the moment I'd be happy with a (cheap) solution that will power my laptop and maybe a light. I'm thinking solar is the way to go, but honestly I'm a bit clueless on this..I'd appreciate any pointers...

I would be thinking theft

embraer170

How much would such a system cost?

quentingargan

Price depends on design, and you need to know;
1) Exactly what the load is, how often it is on. and for how long. So if a laptop is 50W and lights are 10w each, how many hours do each run each day.
2) Can you allow any down time to happen, or does it have to be 100% autonomous?
3) Are devices to be run at 230V AC, or directly DC? You can run a laptop on 24V DC with a DC DC converter if you want to save power
4) Are there other loads you want to use sometimes, such as power tools?
5) What is the roof orientation and pitch? (or do you want to mount at the optimal winter angle of about 65 degrees facing south?

If you want to put up a full list of loads, and the time of day they will be used, I can put a simulation together for people to view here.

A stand alone power system will always be more expensive than conventional energy because of the ancillary equipment involved.
Such a installation is not about return of investment. I don't cater for those sort of systems mostly because often those who do have to compromise the system to do so or have to work to best fit ie. shortfall in Winter abundance in Summer, acceptable losses etc..

I design bespoke minimum self-consumption systems with optimised performance, reliability and redundancy so it's how long is a piece of string I'm afraid.
Most people who approach me looking for a cheap solution, I send elsewhere because I can't compete with systems that don't stand up to their ratings or performance claims. Everything I recommend I've tested and use myself.

I can price up the above but it'll be when I get around to it I'm afraid.

The way I look at it is you end up paying way over the market price for power to reduce expenses elsewhere. If you don't need services then unviable sites or lifestyles are suddenly attainable.

Eg. Houses with services and planning permission are expensive, narrowboats with a mooring are comparatively less so. Granted installation costs for power on a boat will be vastly more expensive but it will work for a decade with minimum upkeep and facilitate a less expensive domestic annual outgoing. You can pay €500 a year for shore power to keep batteries charged or €500 once on solar pv.

My systems do this to batteries as a matter of course, you won't build that from a catalogue.



Upfront costs are above the mean because I include fit for purpose metering, automation & isolation, the hidden expenses of premature battery renewal from poor charging and imbedded parasitic losses are mitigated.
I only spec inverters where they are needed, and good quality ones too.
Diversion loads contrary to popular belief do not need to warm an inverter enroute to the dump load. Those that do need to be 230VAC are not transient generators slowly deteriorating the rest of the appliances active on the house phase.

Given the choice between cheapest and most suitable I cater for the latter. Hence I make systems that work in preference to financial investments.

my3cents

@ Sir Liamalot, many thanks for including the pdf files of your diagrams.

For anyone else who like me was looking to see the finer detail of the diagrams you'll find the pdf files have all the detail. I was interested to see what the wire sizes were.

I have a habit of not using less than 1.5mm² for vibration resilience due to having "trained" on mobile installations. Most of the spec is voltage drop oriented, there's wiggle room on cost versus performance.

my3cents

Sir Liamalot wrote: »

I have a habit of not using less than 1.5mm² for vibration resilience due to having "trained" on mobile installations. Most of the spec is voltage drop oriented, there's wiggle room on cost versus performance.

My interest is that I have a 30 ft static caravan that we sort of inherited with the house. Its handy space and is plumbed in for water the septic tank and has full mains electric. I keep thinking that it would be a useful solar off grid project.

Because it has mains power it already has 240V lights and I was wondering if I could get away with using any of the existing cable (obviously after isolating from the mains first) for 12 or 24V LED lighting. Looks however that it will all need rewiring.

Edit> Question can the batteries be stored in a ventilated area in the caravan (under main seating area)? I'd like them outside but the area floods and the caravan is elevated above the flood level (water can flow underneath it).

ED E

my3cents wrote: »

Edit> Question can the batteries be stored in a ventilated area in the caravan (under main seating area)? I'd like them outside but the area floods and the caravan is elevated above the flood level (water can flow underneath it).

Packs rated for it surely can, thats how campervans do it with the "leisure" cells. 3x 110A gives you a fair bit of runtime at 12v.

I'd be inclined to fit a new system unless you are willing to have an electrician do an installation test.
Even so mains and extra low voltage are entirely different ballgames. I'm not saying it's not doable just not recommended.

You can do both and run a combination of low voltage and extra low voltage depending on the supply availability.


RE batteries:
They derate with cold (outside).
li-ion ignite if you use them sub zero (cell temperature).

Depends on how concerned you are about hydrogen.
You can use hydrocaps on traction batteries.


I tend to seal a compartment and vent it with fish tank tubing.
The sealed leisure battery route which works out as poor performing and more expensive than 6v motive batteries have tubing nipples for venting.

my3cents

I was thinking of making a separate box under the seats that was open to outside with large vents through the floor.

I'm rather taken with the idea of staying low voltage and then seeing how I can fit it out to make the most use of it.

Current 240V fridge would need to stay as that was new last year but thats the only item that would have a large current draw or need 240V AC so I would keep the mains supply just for the fridge. Cooker is gas.

Other than lights the only other things that are in constant use in the caravan are are wireless router and a laptop.

Hydrogen is super leaky a pinhole will do the job. Ideally the box would be insulated.

The electronics will want a regulated supply. 12v batteries have an operational range between 11.8v (as low as 10.5v if you abuse them) and 15.5V (equalisation).

I charge flooded batteries at 14.8V + temperature compensation (usually adds 0.3V) and discharge cut-off at 12.0V.

Probably better off go 24v because PV and cable is cheaper, you can use domestic PV modules. Voc >30
Then use a truck charger job for the laptop and a 24v->12v converter for the router (if the router is 12v which most are).

You'll need a big true sine inverter to start a mains fridge compressor. ~1kVA high frequency or ~700VA low frequency. I'd leave the fridge on a mains/shore feed cos the inverter will be super lossy if it doesn't hibernate.
Don't be tempted use a gas fridge either, they're muck. 8 times less efficient than a compressor and the thermostat is manually operated. :rolleyes:

This is something I've been using to test chargers and charge controllers.
Current battery 8yo FLA starter on bench showing signs of recovery.



I've a selection of low frequency inverters not connected nor is the 12kWh AGM in the space jacket wired currently.


It powers lights and 12V appliances including the 14.4v drill.

Installation is grid-connected so artificial mains waves aren't a priority.


110Wp attached to the MorningStar Ecopulse.
The Victron charger is absolute muck, currently testing a Ctek but I build my own chargers that work better than most you can buy, by feeding SMPSs into MorningStar MPPT controllers.


Ctek under test.
EcoPulse under test.
Victron IP1215 failed to make grade seeking new home.
Victron BMV failed to make grade.
Mastervolt SOC meter & mass combi failed to make grade.
Sterling Power ProCharge Ultra failed to make grade.
Several off brand jobs failed too.
Studer...coo-ar batteries usually fail before inverters.



MorningStar passes with flying colours every product every time although the EcoPulse has some annoyances I've been in touch with the makers about.


SOC metering not connected but have in storage also.

110Wp

Averages 350Wh to 700Wh p/d.








Installation costs :€15


Panel: donated.
HD brackets: €10
Wall anchors: €5
Cable, conduit & wooden risers: salvage.


15° South.


I've got bigger but no need for what I'm using it for.

An_Toirpin

For the remote cottage scenario would installing the panels on the ground save money and is this only feasible for PV or PV and solar thermal?

my3cents

An_Toirpin wrote: »

For the remote cottage scenario would installing the panels on the ground save money and is this only feasible for PV or PV and solar thermal?

Might also be easy for them to be stolen?

Solar thermal needs to be close to your storage tank to mitigate system losses.

I'm not a fan of permanent and semi-permanent ground arrays. Why compete with agriculture?
You'll have more losses due to shading and vegetation.

Cheaper for a DIYer maybe, outbuildings and wall mounted are the best compromise.

If you are getting them installed by a company; any barns or sheet metal roofs are quickest and cheapest due to the foundations already being in situ.

Ground arrays are definitely not cheaper after you remount them on the roof because you want another polytunnel in the garden.

If you are going the battery road 24v (nominal voltage lead acid) batteries and 60 cell panels or 48V batteries and 120 cell panels (2 x 60 series) with PWM controllers are every bit as good as MPPT systems and a hellova lot cheaper.

60 cells are the perfect Vmp for these batteries, there are simply no losses if wired well for an MPPT controller to recuperate.

Don't believe the hype either. MPPT is only 10% better than PWM with standard panel configurations (72 cell for 24V) unless you deliberately mismatch the panel to battery voltage moreso.

I've been monitoring a 60 cell panel ona MPPT controller and it's maximum power point in Irish climates is no better than a basic PWM controller will do for you.
I'll get around to generating some real data at some stage, with parallel identical systems running, the only difference being the charge controller topography...it's on the to-do list....

I can explain it mathematically too if anyone cares, there's a bit to it.
Installers like MPPT because they can charge extra and it compensates for their lack of homework.

Wooden mounting systems won't last, angle aluminum is the best foot forward.

If you set the ground mount above sheep height you can to an extent share the space more often than not.

Solar panel large enough to power voltmeter.
Will be upgraded to 150Wp PWM as soon as client finds enough sofa change.





BrownOut ~15% Overload








Ain't nothin' fancy.

Built from scrap for a low price.

150Wp installed.



Sofa Change was found and time was donated in an effort to prevent certain parties molesting all my orphan starter batteries.

Currently it's running lighting with some off-site recharging. System will come into it's own come March where it'll be able to run some basic power tools too.



And yes I do know that solar charge controller is 90° perpendicular to correctly optimised heat sink operation...if it gets upset I'll do something about it.

unkel

Sweet Jaysus a tiny single panel. Would you not install at least a few kWp?

For three light bulbs and an occasional drill?

Besides its not my installation.

As a side note I can meet most of my lecky demands throughout the year with 265Wp.

unkel

Sir Liamalot wrote: »

I can meet most of my lecky demands throughout the year with 265Wp.

You're a frugal man so

It's a feedback loop; everytime I ran outtov youtube power I redesigned the system. :pac:





Nice not having bills though. :P

unkel

Bitcoin mining worldwide is mostly run on renewables. Even in Bitcoin mining heaven China

I'm not mining Bitcoin, BTW. Not because of the electricity consumption, but because it needs dedicated ASIC miners that turn from profitable to completely obsolete within a few months. Not even leaving any recoverable / re-usable parts. I use only normal PCs with normal PC parts that have a full second life left for many years after I use them for mining, and all those parts are easy to resell (re-use)

Arah I was teasing Unkel. Hospitals use a lottov power too.

unkel

Hope you have enough oomph left in your batteries to cool the champers down for a toast tomorrow night :pac:

Ooh I usually keep about ~300kg fully charged at all times..just in case....:pac: