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OtleyLad

Solar by numbers?

As you know I've recently got myself qualified as an electrician as well as MCS certified. As a result I know full well the pitfalls and potential dangers of dabbling with anything electrical. Also how valuable actual practical experience is needed as much as theoretical.
That said most of the electrical work I do is using tried and tested methods and materials. I.e. if its an average ring main you use 2.5mm cable; lighting 1.5mm, standard sockets, switches, etc, etc.

What I want to do is set up a set of recommended systems for Off-Grid solar PV installations. Watching many discussions on here and other forums I feel a lot of people are put off (and sometimes put down) by over-complicated explanations that go way beyond what is needed for the average DIY person to put together a safe/effective system.
I know there are some people here who are much more knowledgeable than me on the subject who might help?
Crucially with the specific components named (with example prices). This might stop a lot of enthusiastic people buy mismatched components that either never work together or fail early.
Why do I want to do this? Well I've started a group in Otley (now named Practically Green) and will soon be putting together a website with all manner of info on how to live a greener life - based on local conditions (i.e. what grows well here, what's available locally, best use of solar PV, etc).

Here's what I'm thinking of:

A set of systems (including wiring specs and layouts) suitable for powering different sets of devices - and perhaps a couple of example prices and suppliers for each.

Examples:
A low power set - charging phones, shed lights.
Mid range intermittent - Pumps, small electrical tools, PCs, Laptops and the like.
Mid range continuous - fridges/freezers...

Of course there are endless combinations and applications but in the end I'm sure most can fit into one of only a small set of categories with a few options for each depending on the use (for example MSW or PSW inverters).

What do you think?
Graham Hyde

Hi Otley lad.
I welcome your setting up the Practically Green group but solar or any other off grid system in my opinion should not be included.
We all know that an off grid system will not save money, the batteries alone (cheapest deep charge cycle 75 pounds each x 20 = 1,500 pounds and last about three years) take care of that. As for the enviromental issue, if you already have a mains supply you are installing an addition generating and battery system. The energy used to manufacture these items and transport them is a lot more than the that used by the generation of the mains electricity.
The only sensible use of off grid systems is that, when you are off grid the rest is just a con.
Regards, Graham
Graham Hyde

Hi Otley lad.
I welcome your setting up the Practically Green group but solar or any other off grid system in my opinion should not be included.
We all know that an off grid system will not save money, the batteries alone (cheapest deep charge cycle 75 pounds each x 20 = 1,500 pounds and last about three years) take care of that. As for the enviromental issue, if you already have a mains supply you are installing an addition generating and battery system. The energy used to manufacture these items and transport them is a lot more than the that used by the generation of the mains electricity.
The only sensible use of off grid systems is that, when you are off grid the rest is just a con.
Regards, Graham
OtleyLad

Hi Otley lad.
I welcome your setting up the Practically Green group but solar or any other off grid system in my opinion should not be included.
We all know that an off grid system will not save money, the batteries alone (cheapest deep charge cycle 75 pounds each x 20 = 1,500 pounds and last about three years) take care of that. As for the enviromental issue, if you already have a mains supply you are installing an addition generating and battery system. The energy used to manufacture these items and transport them is a lot more than the that used by the generation of the mains electricity.
The only sensible use of off grid systems is that, when you are off grid the rest is just a con.
Regards, Graham


Sigh - there's always a naysayer wanting to add their negative twopenneth.
I'm not asking for a debtate on the pros or cons of Solar as you can see if you read my OP. If you've nothing positive to contribute please keep you views for more relevant threads.
tahir

Sigh - there's always a naysayer wanting to add their negative twopenneth.
I'm not asking for a debtate on the pros or cons of Solar as you can see if you read my OP. If you've nothing positive to contribute please keep you views for more relevant threads.


If you don't want people to be honest then why post on a public forum? It's his opinion, based on what I believe is his own experience. You can take it or leave it but to respond in the manner that you have is in my opinion uncalled for and serves noone.

I am quite sceptical of the environmental benefits of battery based solar systems for the same reasons as Graham, they ain't really that cheap or green!
OtleyLad

Sigh - there's always a naysayer wanting to add their negative twopenneth.
I'm not asking for a debtate on the pros or cons of Solar as you can see if you read my OP. If you've nothing positive to contribute please keep you views for more relevant threads.

If you don't want people to be honest then why post on a public forum? It's his opinion, based on what I believe is his own experience. You can take it or leave it but to respond in the manner that you have is in my opinion uncalled for and serves noone.

I am quite sceptical of the environmental benefits of battery based solar systems for the same reasons as Graham, they ain't really that cheap or green!

My response is uncalled for? I was simply asking for ideas on system configurations - not to hear people's negative dumping.
tahir

not to hear people's negative dumping.

To which I repeat, this is a public forum, people have opinions that may differ from yours. They may choose to express them, if this disturbs you then you need to rethink whether you should be posting for advice on a public forum, maybe you should have subtitled the post "Positive vibes only"?
crofter

Re: Solar by numbers?

You did ask

What do you think?

FWIW I agree with Graham.
Graham Hyde

Hi Otley lad,
I'm sorry if I upset you. It was not my intention.
If you re read my email ( you may have missed this focusing on the negative part) I support you setting up the Green group in Otley.
My concern was you including a non-green item.
I used to be involved in Grren issues when working and part of my role included lecturing at Green events. The largest audience I had was just over 1,500 paying delegates. Cost of attendence was the equivelent of 150 pounds,. there was howerer more than just me talking.
Please keep submitting post, I always l look forward to opening 'Otleylad'.
Regards, Graham
Pilsbury

As i have mentioned before i would love to set up a single panel linked to a battery with car charging ports available for my phojes, ipads, tablets and so on, it might cost more than the electricity it generates but if we are ever going to brek away from carbon based electricity i beleive every little helps.
If every house had a small appliance charging station demand from the grid would drop.
The next step up for me would be a shed based system which would probably be high demand for short periods if i ever got round to wood working again.
I have zero knowledge or experiance on this but i hope you can accheive what you are aiming for.

As for the negatives above i do understand what your saying but another way to look at it is to say why bother installing a woodburner if ypu already have central heating and yet that principal is heavily endorsed on downsizer....
Nick

I think it's the fact that the batteries and solar panels require far more regularly sourced (coal made) electricity to produce than they will ever save. The same is not true for a wood burner. tahir

why bother installing a woodburner if ypu already have central heating and yet that principal is heavily endorsed on downsizer....

I agree, and although we have one it wasn't my idea and I don't really endorse them, they are more polluting than coal, the only benefit is that you're not using fossil fuels.

Much better to reduce demand (always)
Nick

I would, however, like to see Solar for Dummies. tahir

I would, however, like to see Solar for Dummies.

Not a bad idea, but it's not a brilliant solution finacially or environmentally, although it certainly has it's uses
Nick

Probably not, now. However, the same is true of electric cars. But, if we don't shift units now, the barriers for reducing the costs won't ever happen. Battery technology is rocketing forward, because there is a demand for it.

Also, regardless of the 'costs' if brown outs are likely to become possible, it's an alternative.
tahir

Like I say it has it's uses, and it will inevitably get to a point where the panels are cheap/green to make and battery tech is also more useful/chepaer/greener than it is now Graham Hyde

Hi all.
I was involved in a small solar panel scheme.....2,500 solar panels at Energy City Abu Dhabi. As you are aware, there is lots of sand there abouts and it gets quite windy...like nearly every day in this location.
Had an automatic washing system (water was obtained by desalination...a very energy using system).
However, the publicity could state the designed output of this solar system. Green, I think not.
I gave a lecture in Qatar, sponsered by another Energy City.
The site of the development was a green field site (actually a piece of empty desert outside Qatar city). If they had turned the whole site (grid layout) 90degrees they would have saved 15% of the energy fees. I did not mention this in my lecture and received a solid gold model of a dhow as a show of thanks.
Lots more experiences...
Regards,
Graham
tahir

Graham, unfortunately most of it is greenwash. Either we'll sort it out or we'll be extinct, I still reckon we'll sort it out but you never know. OtleyLad

Ok would people like to suggest some systems for the following:

System 1
To power a security light/internal lights. That is for intermittant lighting use (2 or 3 LED lights for max 3hrs a day in mid-winter).

System 2
A security light/internal lights and charge a laptop/phone/etc. That is for intermittant use (2 or 3 LED lights for max 3hrs a day in mid-winter).

System 3
Power a large freezer that uses 268kWh per year.

System 4
Power a fridge that uses 117kWh per year

System 5
Run 2 or 3 LED lights and a PC for up to 8hrs a day 5 days a week all year round.

So you'd need to specify for each:
Panels, charger,controller,batteries, optionally inverter (if using 240v lights, etc).
dpack

without trying to be negative i can see the value of pv if there is a good chance of sunlight,there is no other sensible alternative or it is convenient to use such as to keep a leccy fence topped up between charges etc .

trying to be positive for a fairly green solar powered thing pre heating/heating water seems a good un
madcat

Otley Lad there's a lot of use of and experience of solar systems in the Narrowboat community.
My boat is effectively an off grid situation where all power away from the mooring comes from batteries charged by the engine alternator. This is a 12v system using small solar panels as trickle chargers when the boat isn't in use.

I have a simple system and carefully control my energy usage but others have large ( in terms of available roof space) solar arrays and are looking to run such items as fridges which are notorious energy vampires.

You can find out a lot by searching the topics on Canal World forum . I recommend a lot of reading before joining and asking questions as not everybody on there is pleasant or constructive. Downsizer is much more civilised.
I never deploy virtual teeth and claws on Downsizer but have shaped up for a hissy session on CW in the past .
OtleyLad

Well I've done one:
System 2
A security light/internal lights and charge a laptop/phone/etc. That is for intermittant use (2 or 3 LED lights for max 3hrs a day in mid-winter).

I've called it a 250w Charging Station

This system uses a 250w solar panel (shown here outside the conservatory). It will go on the garage roof soon. The panel feeds electric into the charger:

The charger safetly feeds the electric into a couple of 12v 88ahr batterries so the system can be used 24/7.
In the conservatory is the charging 'station' that includes an invertor (to up the voltage from 12v dc to 240v ac) for charging laptops and a set of USB ports for charging phones and tablets.

So far so good. It may be that we can drive the conservatory lights off this as well, but first I'll see how it goes for a few months.
vegplot

Given time the box will float away buoyant with hydrogen. OtleyLad

Given time the box will float away buoyant with hydrogen.

There are plans to drill holes in the top to prevent that - but not so people can poke fingers in there...
vegplot

Given time the box will float away buoyant with hydrogen.

There are plans to drill holes in the top to prevent that - but not so people can poke fingers in there...

I wonder how explosive my set up is. I have my batteries in a timber compartment and give myself, perhaps ill founded, confidence it's in an exposed porch.
wellington womble

I really could do with one of those for the caravan. Do you reckon someone who has never wired a plug could do it? (And you can all shut up. I've never needed to wire a plug. If the opportunity arises, I'll be happy to have a go.)

Is your conservatory secluded and secure? I see why you want it there, for the lights, but I think I'd be nervous about keeping my electronics in there (but then I'm totally paranoid and take mine to bed with me!)

How much do you reckon it cost?
crofter

I would not worry about the box floating away, most likely that plastic is permeable to hydrogen and you will never trap enough to defy gravity, but agree with vegplot that ventilation is needed (high up in the conservatory, as well as in the box) to stop potential build up of explosive gas. I also wonder if that plastic box might build up a static charge...

I would cut that piece of conduit on the left about a foot shorter and clip it onto the brick wall & clip the rest of the cables as well, to leave a tidy job.
vegplot

keeping my electronics in there (...take mine to bed with me!)



Too much info.
crofter

Just noticed that the batteries are outside? Proper ventilation! dpack

nice but the inverter to lappy thing might be a bit ambitious.iirc my big batteries are 80 amp hours each and a full one would run my lappy via an inverter for about 10 hrs

some lappys are less greedy than mine but they are quite power hungry and there is a loss at the inverter stage of about 15% for most

for led lights and similar stuff that looks like a good rig
vegplot

Power your laptop direct from 12volts and avoid all the inverter lark. Manufacturers don't make it easy though. dpack

if only it was simple .mine feeds at 19 v ,so not only the inverter loss but the lappy transformer as well as the internal conversion from battery/direct feed to the board voltages

im sure most of this sort of thing is due to historic choices about electronics working voltages ,battery efficiencies etc but a pooter that could feed direct from a 12 v supply (or a simple splitter to 6)would be ace
Hairyloon

if only it was simple .mine feeds at 19 v ,so not only the inverter loss but the lappy transformer as well as the internal conversion from battery/direct feed to the board voltages

im sure most of this sort of thing is due to historic choices about electronics working voltages ,battery efficiencies etc but a pooter that could feed direct from a 12 v supply (or a simple splitter to 6)would be ace
If it is designed for 19V, it will probably work on 18V...
wellington womble

keeping my electronics in there (...take mine to bed with me!)



Too much info.

I should clarify that I am discussing my wordly goods, which consist of my iphone, ipad, current knitting project, wallet/chequebook, file of Important Documents and back up external harddrive). It means if I hear noises in the night I can bury my head under the duvet and know that unless they nick the coffee, I can sort it out in the morning, and if there is a fire, we can exit the building with our actual and administrative lives intact!
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