Wiring Regulations for Off-grid Home

brianwake · 14-05-2017 12:52pm #1

Hello
I am adding a PV solar array to my off-grid holiday home which is currently running from a generator.
Does anyone know if there are Electrical Regulations directly applied to Ireland regarding the Solar panels and Battery storage system?

antoinolachtnai · 14-05-2017 1:12pm

brianwake wrote: »

Hello
I am adding a PV solar array to my off-grid holiday home which is currently running from a generator.
Does anyone know if there are Electrical Regulations directly applied to Ireland regarding the Solar panels and Battery storage system?

It is a complicated question. In the end it is a matter for your insurance company I think. I don't think they will be interested in insuring a house which has an electrical installation but doesn't have and never had a wiring cert, no matter what the law is. An uninsurable house is not really marketable and thus not really worth anything. It is a very bad idea to invest your savings in such a house.

Calahonda52 · 14-05-2017 3:26pm

Section 712. pgs 217 to 220 of the current National rules for elec installations deal with it, but only in the context of the expectation that the PV /AC setup interfaces with the ESB supply, which is not the case here.
It makes no reference to battery storage.
So you can get a cert to cover off the points raised in post above, a cert does not oblige you to have a grid connection, usually one in got to enable grid connection

quentingargan · 15-05-2017 8:02pm

Electricians will have the RECI rules for wiring both DC and AC. When you are off-grid, there is no enforcement system, so I have seen some pretty Heath-Robinson systems that I would consider to be a fire hazard in my time.

Remember that a battery is a source of almost infinite current, so you need proper DC MCBs or fuses protecting each component of the system, and cables must be sized to match the current rating of the MCBs chosen. An off-grid system like this has three components - DC from solar, DC from batteries, and AC from inverter. If you aren't sure what you are doing, I would get professional help.

dingding · 02-04-2018 12:46am

OP did you put in an off-grid system and if so what did you put in. Also any feedback on how it is working pros / cons etc....

Thanks

quentingargan · 02-04-2018 10:13pm

Since last year, some new equipment has come to the market and Li-ion batteries with battery management have come down in price, so actually solar off-grid is a lot more straightforward than it used to be.

One inverter can push solar into batteries and load, and later provide power after sundown using the same inverter to run off batteries instead of solar.

03-04-2018 2:36am

Electrical regulations apply to those connected to a network.

quentingargan wrote: »

When you are off-grid, there is no enforcement system, so I have seen some pretty Heath-Robinson systems that I would consider to be a fire hazard in my time.

I see your houses and I raise you boats and campers! :pac:

quentingargan wrote: »

Since last year, some new equipment has come to the market...
...One inverter can push solar into batteries and load, and later provide power after sundown using the same inverter to run off batteries instead of solar.

That's not new it's just a variation.
Studer and a few others have been doing it for decades.

quentingargan · 03-04-2018 9:03am

Sir Liamalot wrote: »

That's not new it's just a variation.
Studer and a few others have been doing it for decades.

That's interesting, but if I read the data right, max is 4 solar panels and the charging is PWM rather than MPPT?

The units I'm looking at are solar grid-tie inverters in the range of 3 to 5kw with ESS options that can invert up to 3kw from the batteries. Downside is that they only work with Li-ion. Target is the ESS market, but I think they might be an option for some off-grid that is solar only.

03-04-2018 11:26am

I've never been a fan of combi units. Inverter manufacturers can't make chargers. You pay a lot for convenience.

Yeah that Studer is strictly small scale but it is a 20yo design afaik. They're not the only inverter manufacturer with integrated solar charge controller.

quentingargan wrote: »

Downside is that they only work with Li-ion.

That's a rather big downside.
Sounds like a 4x4 for going to the supermarket.

quentingargan · 03-04-2018 5:55pm

Sir Liamalot wrote: »

That's a rather big downside.
Sounds like a 4x4 for going to the supermarket.

Yeah, but running your house on four panels is a bit of a downside too.:D

dingding · 04-04-2018 12:05am

Any links to sellers / suppliers of off grid systems and recommendations for good products.

04-04-2018 1:09am

quentingargan wrote: »

Yeah, but running your house on four panels is a bit of a downside too.:D

Yurp.
But that unit is for a hunter's lodge/holiday cabin/recreational craft. The MPI has more capacity and MPPT.

Not that I'd recommend either.

The bigger downside of that Studer is the absence of a 2.47V p/c charge setting or programmability.

As I said you pay a lot for convenience.

quentingargan · 04-04-2018 7:07am

dingding wrote: »

Any links to sellers / suppliers of off grid systems and recommendations for good products.

I've used Outback and Victron - I find Victron now more progressive. Sir Liamalot also put up a link to Studer. If you want info on resellers, you would need to invite a PM.

dingding · 04-04-2018 10:00pm

quentingargan wrote: »

I've used Outback and Victron - I find Victron now more progressive. Sir Liamalot also put up a link to Studer. If you want info on resellers, you would need to invite a PM.

Something like this?

http://www.energyfreedom.ie/Projects/Victron-system-Sligo

05-04-2018 12:58am

I use MorningStar & Studer.
I make my own chargers from solar controllers because I never found a good one off the shelf and I'm tired of wasting money on them.

I have some Victron, Sterling & MasterVolt stuff but I don't like them.

brianwake · 03-06-2018 6:41pm

dingding
To answer you question yes I did go ahead with the project .
To capture the suns energy I installed 4 280 watt PV panels.
Then a Victron Blue Solar MPPT charge controller to look after charging the batteries.
Next is the Multiplus Compact to convert the battery power into mains power to power the house. This unit also allows you to charge the batteries with petrol generator, but I haven’t needed to yet

07-06-2018 9:14pm

Are you using lead acid? Does that victron charge controller get the battery to specific gravity 1.275?

brianwake · 08-06-2018 7:40am

Sir Liamalot wrote: »

Are you using lead acid? Does that victron charge controller get the battery to specific gravity 1.275?

Using Victron Lithium lifepo4 batteries. Better depth of charge and should last longer.

freddyuk · 09-06-2018 6:20am

Just finished installing a set of Aquion batteries into Victron Quattro (with ccgx controller) AC coupled to my existing PV grid tied system (5kwp). Of course the past week has been "exceptional" Irish weather but have not used the grid at all. No major lifestyle changes. Battery capacity 25kWh. Using about 20% of that per night which could be cut down as we have three freezers running and they are not 'A' rated and other standby loads around the house are still on.
It shows me that having a back up generator sized to recharge daily usage will enable us to go Off grid without any dramas. Maximum DOD was 46% so far but Aquions can go to 100% DOD without any problem BUT they are not available at the moment as the company went bust last year.
AC Electrical connections were checked by my electrician but everything is according to the manufacturers instructions and best practice.
Victron ESS software handles all the system automatically and will allow export of surplus generation to the grid however Irish regulations prevent this so it is not exporting at the moment and any surplus can be diverted to the hot water although the batteries can soak up most of this anyway.

The batteries will be boxed in and left to their own devices for I hope in excess of 10 years.....no servicing required.

09-06-2018 10:14pm

brianwake wrote: »

Better depth of charge and should last longer.

300Ah @ 24v Victron "smart" LiPo ~€7000 + Vat
Cycles to 80% DOD: 2500
Energy to 80% DOD: 5.76kWh
Energy over lifetime: 14.4MWh

Cost per kWh lifetime:€0.49 + Vat

1260Ah @ 24V Flooded Traction OPzS: ~ €2280 + Vat
Cycles to 80% DOD: 1500
Energy to 80% DOD: 24kWh
Energy over lifetime: 36MWh

Cost per kWh lifetime:€0.06 + Vat

air · 14-06-2018 10:06am

Unfortunately the low user service charge further penalises anyone going with a grid tied battery backup system at present, pushing out the payback even further.
For a new build there's a lot to be said for going off grid with a generator unless you want a large heat pump and / or an EV with a lot of travel.

14-06-2018 10:21am

I don't think anyone ever factors real world charger - inverter efficiency of battery cycling.
As a rule I take the manufacturer quoted efficiency and reduce it by 35%.
Reduce that another 15% if you AC couple.

That puts a fair dent in payback.
Even with my freecycled 12kWh AGM it's more valuable to me as a standby offline supply.

You're doing off grid right when you're not using the battery.

antoinolachtnai · 14-06-2018 10:25am

air wrote: »

Unfortunately the low user service charge further penalises anyone going with a grid tied battery backup system at present, pushing out the payback even further.
For a new build there's a lot to be said for going off grid with a generator unless you want a large heat pump and / or an EV with a lot of travel.

Not all the suppliers have that do they?

What is your capital cost and running cost overall?

14-06-2018 10:36am

Like building sports cars. If I added up my spend I wouldn't be doing it.

...and I'm a born cheap-skate

air · 14-06-2018 10:58am

antoinolachtnai wrote: »

Not all the suppliers have that do they?

What is your capital cost and running cost overall?

Not sure, but Electric Ireland have it and I'm stuck with them as I'm on their FIT for export - for as long as that lasts.
It doesn't make sense for me to disconnect personally as the re-connection charges are excessive if I ever wanted to sell the home.

My running cost should be close to zero this year anyway as I have low usage (circa 1000kWh per annum import) and a large PV array.

If I was to build a new home I'd go off grid and avoid the connection and certification costs etc.

14-06-2018 11:25am

air wrote: »

If I was to build a new home I'd go off grid and avoid the connection and certification costs etc.

This is the only way it's cost effective imo.

antoinolachtnai · 14-06-2018 11:28am

Sir Liamalot wrote: »

This is the only way it's cost effective imo.

Will a bank give a mortgage to build a home which is intended to be off-grid?

Will an insurer insure a house with an uncertified electrical installation?

14-06-2018 11:34am

If you have to ask... (yes & no)

It's very difficult to get a mortgage when you don't have bills.

Gumbo · 14-06-2018 2:28pm

Also, a new home requires a BER Certificate.
A BER Certificate is linked to your MPRN number.

14-06-2018 2:39pm

I think the definition of off the grid is misinterpreted.

Why go to all the trouble to be self-reliant and then ask for a pat on the head from the state?

If you want to save money, save money. If you want a saleable house follow the crowd.

BryanF · 14-06-2018 2:40pm

kceire wrote: »

Also, a new home requires a BER Certificate.
A BER Certificate is linked to your MPRN number.

So if you don’t have an MPRN?

Wiring Regulations for Off-grid Home

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