Hybrid off grid solar

Bricken

I have looked at a few websites. some offer diy systems around £7000 others offer to supply and install but when it comes to details and price they want to send a rep. I hate reps they really dont understand terms like leave now or conman so if you live in the north west and have a hybrid system that you are happy with. I have ssw pitched slope with no shaded areas i am looking at a 12 panel system how much did it cost you. So i have an idea before i get into it with the reps.

EricMears

Bricken wrote: »

I have looked at a few websites. some offer diy systems around £7000 others offer to supply and install but when it comes to details and price they want to send a rep. I hate reps they really dont understand terms like leave now or conman so if you live in the north west and have a hybrid system that you are happy with. I have ssw pitched slope with no shaded areas i am looking at a 12 panel system how much did it cost you. So i have an idea before i get into it with the reps.

Can't help directly (I'm not in NW and my system isn't standalone) but a few points nevertheless :-

12 panels used to mean 3kWp but understand you can now get panels bigger than 250Wp. Even so, basic system (without island function) unlikely to cost more than a 16 x 250Wp one which I understand is coming in at around £6k.

To convert that to an 'island' system you'd need to add one (maybe two) of the Sunny Island units I mentioned earlier giving a potential total of £7k or £8k. You might be able to negotiate a better price than that but laugh at any offers above it.

But don't go down the DIY route ! You'd have to pay 20% vat rather than the 5% that a MCS registered installer could charge and you wouldn't be able to claim FIT payments (the generation payments do still apply for self-contained systems but obviously you won't get the export payments).

rogerblack

Bricken wrote: »

I have looked at a few websites. some offer diy systems around £7000 others offer to supply and install but when it comes to details and price they want to send a rep. I hate reps they really dont understand terms like leave now or conman so if you live in the north west and have a hybrid system that you are happy with. I have ssw pitched slope with no shaded areas i am looking at a 12 panel system how much did it cost you. So i have an idea before i get into it with the reps.

Do you mean an actual disconnected from the grid system that is never connected at all?

This is hugely expensive, in general, and only sensible if your alternative is running a generator.
You will also not get much power at some times of year.

If you mean Liverpool, then the average output for december pointing south with a 3kW array is about 90kWh. If you mean Fort William - it's 45kWh.

That is - 3kWh/day - or 1.5kWh/day. And you then need to knock off 50% or so typically at best for battery charge/discharge efficiencies.

1.2kWh/day will run an efficient fridge/freezer, one very small energy saving light bulb for a few hours a day, and a laptop for a couple of hours.

Martyn1981

Bricken wrote: »

I have looked at a few websites. some offer diy systems around £7000 others offer to supply and install but when it comes to details and price they want to send a rep. I hate reps they really dont understand terms like leave now or conman so if you live in the north west and have a hybrid system that you are happy with. I have ssw pitched slope with no shaded areas i am looking at a 12 panel system how much did it cost you. So i have an idea before i get into it with the reps.

Hiya Bricken. Firstly, Eric beat me (on both threads) to the mention of Islanding. If you haven't already, have a read of the SMA 'stuff', other companies offer similar kit.

Regarding going off-grid, or 'reduced grid', I've been watching and waiting and reading with interest. Also been chatting with off-griders. Generally the rule seems to be, if you have grid available, stick with it. Reduced grid is very possible, but off-grid is a big jump. Why?

Well, for reduced grid, you can cherry pick, start with PV (grid tied), then maybe move on to some battery back-up for night time lights, and expand from there, but batts are expensive, and don't last too long yet.

As you go further off-grid you'll need to provide for longer, poorer periods of generation, but these will happen less and less often, so you have to spend loads on batts or additional generation, for 4 bad days, then 5 bad days etc, despite those representing a smaller and smaller part of your consumption.

In fact for off-gridders, most I chat with seem to give up at a certain point and have generators for those infrequent times. The challenge of course then becomes how little fuel they can use, by installing 'just a few more' PV panels.

For reduced grid, just replace 'the generator' with 'The Grid'.

There are also more and more systems being offered with integrated battery systems. But these cost mega bucks still, but are heading the right way.

Mart.

Martyn1981

rogerblack wrote: »

That is - 3kWh/day - or 1.5kWh/day. And you then need to knock off 50% or so typically at best for battery charge/discharge efficiencies.

Hiya Roger. Take a seat and get ready for a shock, here's a thread pretty much describing what Bricken might want, or be interested in. Effectively two systems, one a 4kWp GTI system with FiTs and the other a DIY PV plus islanding system.

And the shock part reply#10 "1709 kWh’s has been used to charge the batteries and the batteries have supplied 1524 kWh’s which imply a battery efficiency of 89% which I find quite impressive. It will be interesting to see how this efficiency drops in future years as the batteries age and inevitably sulphate."

http://www.navitron.org.uk/forum/index.php/topic,17834.0.html

Also, reply #13, off-grid with a Lister generator lurking in the pic bottom left.

Mart.

Bricken

Wow i can see i have come to the right place! I have heard batteries are improving as more people are going this route. I am a quick study but can see i have a lot to learn. (tech stuff) more informed in rural survival than urban However some suggestion of power cuts may not require running to the forest if it lasts for just 12 hours or so. If blackouts were to last more than two days i and mine would be rural before civil unrest. so not so concerned about batteries coping long term just for power outs. To run fridge computers and lights.

rogerblack

Bricken wrote: »

To run fridge computers and lights.

If that is your only reason - it's going to be _lots_ cheaper to simply get in a little prepared food to last a week that will store, add 'fridge contents cover' to your insurance, and add something like http://www.ebay.co.uk/itm/NC-APC-750-XL-UPS-24V-Batt-pure-sinewave-inverter-DIY-power-projects-solar-/390617577452?pt=UK_Computing_Uninterruptible_Power_Supplies&hash=item5af29f37ec plus 2* http://www.ebay.co.uk/itm/Leisure-Battery-12V-100AH-NUMAX-LV26MF-Battery-Caravan-Motorhome-Marine-Boat-/190646492545?pt=UK_Campervan_Caravan_Accessories&hash=item2c636a9d81 *2. Or a small, efficient generator and a large can of petrol.


This can provide (about) 2kWh in the event of a power outage.
(Batteries will need replaced every 3-5 years).
Optionally supplement with a small generator.

Bricken

Final post for this thread thanks all for your input. I do not only have survival in mind i do wish to become more independant from big brother and reduce my footprint. If i am going down this road i have to factor in the potential downsides of having an independant power supply. I have enough food for a month.
However Recent data suggests that 3 days without utilities and the veneer of society collapses. A generator is noisy, lights attract attention i dont want to barricade against hungry predators. So every thing is mobile i know where im going. but that is a last resort i hope it does not happen. So for now reduction of bills is my immediate goal. I may do a two phase installation. thats why im here not on a forum for wilderness nuts.

MFW_ASAP

I was interested in living off-grid but came up against all of the issues the posters above have already mentioned. The only way I can see it being feasible to be off grid is if you purpose-build a home with that intention. Finding a suitable plot that had a natural resource such a fast flowing stream or a windy hilltop would help immeasurably with power generation. Hydro is especially useful because unlike Solar, it runs 24hrs.
The next step would be to build a home to passiv-haus standards, with zero heating requirement. A borehole/rainwater/greywater recycling and a cesspit/reedbed filtration system would sort out your water requirements and a combination of solar pv/solar thermal/hydro/wind would provide your water heating and electricity.

The alternative is to retrofit insulation, glazing and green technologies to an existing home and try to reduce your use of the grid. We are following this approach and using a 'rule of thumb' 50% approach, trying to reduce our use of gas, electricity and water by half. Our largest bill is for water and space heating and so we are currently installing internal wall insulation and filling the ceiling voids and lofts with insulation, plus fitting high efficiency double glazing. We also have a 'French drain' around the perimeter of the house which I am going to dig out and fill with a recycled foamglass product. This will give us better drainage, use a recycled waste product and will give us a little bit of insulation. We are hoping that all of the above will reduce our space heating demands and then we'll install solar PV/Thermal to heat our water cylinder and reduce our water heating demand.

The next step is to reduce our electricity usage. As our lightbulbs fail we replace them with LED bulbs. Similarly with our white goods, we have replaced these with A++ units. We also have convection hobs. We may replace our tumble dryer with a heatpump or gas one, though we try and use this as little as possible. Our TVs are all LED and whenever we buy any electrical items, the power usage is high on the list of requirements. Once we have done everything we can to reduce our consumption, we'll look at fitting Solar PV to reduce our dependence on the Grid.

The final utility is water. We will fit a rainwater recycling tank which will reduce our water bill by 50%, by using rainwater to flush the toilets, clean the cars, water the garden and wash our clothes.

As we haven't got bottomless pockets, all of the above will be fitted by ourselves (except the windows) and will therefore take a while! I work at a slow pace, but in some ways this is helpful because by the time I've finished one job, we have the money saved up to do the next one.

rogerblack

Martyn1981 wrote: »

Hiya Roger. Take a seat and get ready for a shock, here's a thread pretty much describing what Bricken might want, or be interested in. Effectively two systems, one a 4kWp GTI system with FiTs and the other a DIY PV plus islanding system.

I've speculated in the past about the use of second hand batteries - they can indeed significantly change the economics.
I have wondered about going down my local scrapyard, and getting a couple of tons of car /leisure batteries for a bit over the price of scrap lead.

When the batteries wear enough that I have half a ton of actually dead ones - swap them out.

rogerblack

I'm in the middle of a project to do something rather less ambitious.

2*150W 28VPSUs, hooked up to 2 110Ah*12V batteries, for a total of 2kWh or so.

2*250W panels.
750W inverter.

Appropriate 'point-of-load' converters to run various household loads from the 24V bus.

Set fridge and freezer several degrees colder than I want them - and run them from external thermostats, biased so that they run from solar (through the inverter.)

LED lights, and various low power loads such as networking gear run from the DC bus.