Solar PV Hints, Tips & Troubleshooting

AmpMan

https://www.boards.ie/discussion/comment/121435107#Comment_121435107

No need for the fireman if you are not getting a grant.

munsterfan2

https://www.boards.ie/discussion/comment/121435901#Comment_121435901

Will end up with 3 strings in total, 2 x 6 ( x360w) in the 3.5kw and 1 x 8 (x360) in the 2.5

SD_DRACULA

https://www.boards.ie/discussion/comment/121436381#Comment_121436381

I see, then yes two of them. I was lucky the installer used 2 of these so can use 4 strings in total.

HotSwap

https://www.boards.ie/discussion/comment/121436132#Comment_121436132

That’s not true. It’s part of building regs / electrical regs unless there is some other means of isolating the DC strings externally or automatically preventing your inverter from feeding back to the grid.

graememk

https://www.boards.ie/discussion/comment/121508745#Comment_121508745

The inverter does that. It's built into every grid tied inverter, it's how grid tied inverters work.

HotSwap

https://www.boards.ie/discussion/comment/121508764#Comment_121508764

Section 5.4.5 of Building Regulation TGD B - Fire Safety (2017) states that “where Photovoltaic (P.V.) panels are provided on buildings, provision should be made for the isolation of the panel array externally and in accordance with ET101, 2008” which has been replaced by I.S. 10101.

 For all live conductors where a risk of electric shock is involved

 Must act as directly as possible on the appropriate supply conductors

 Accessible, readily identifiable and convenient for intended use

HotSwap

https://www.boards.ie/discussion/comment/121508764#Comment_121508764

Backup operation is permitted so long as the below conditions are met;

- The backup supply from the PV and battery energy storage system must be on the load side of the ESB meter and cannot feed any other premises.

- The requirements of I.S. 10101 must be met, particularly relating to the requirements of ‘standby supply’ and break-before-make changeover switch, and the requirements for neutral treatment in island mode and impacts on protection operation.

- There can be no circumstances where the PV and battery system will feed energy into the grid during backup operation.

- Ensure that, by design, loss of mains (LOM) protection is not compromised. This could be either by relocating LOM to ESBN-Customer interface or by interlocking LOM changeover switch.

HotSwap

https://www.boards.ie/discussion/comment/121508792#Comment_121508792

@graememk how are you suggesting one should comply with this reg?

AmpMan

https://www.boards.ie/discussion/comment/121508745#Comment_121508745

Can a solar inverter can feed back to the grid if it has no AC supply ?

10-10-20

https://www.boards.ie/discussion/comment/121508792#Comment_121508792

The way I read it...

provision should be made for the isolation

...is not definitive, so it's recommended but optional.

EN50549 (superseded by I.S. EN50549-1) and requires that each generator have "Means to detect island situation" as detailed in part 3.8. So if fire-safety is the concern then the meter box needs to be marked with the regulatory stickers as per part 3.14 (Labeling).

At the ESB Networks metering position of a location where a Micro-Generator is installed

https://www.esbnetworks.ie/docs/default-source/publications/conditions-governing-the-connection-and-operation-of-micro-generation-policy.pdf

graememk

Big difference between should and must.

Regarding off grid use/changeover switch - The changeover switch is an interlocked device that will isolate the grid from the inverter. same if you were running a generator.

Argument could be made that in attics the DC isolators are not accessible vs if they were on an outside wall. The fireman switch is not for anti islanding, but is for the fire regulation as you have said. Its still a should, not a must.

HotSwap

https://www.boards.ie/discussion/comment/121508852#Comment_121508852

The answer would have to be yes; many inverters have a “emergency” AC output that is always live; and would remain live in a situation where the grid power is down (and no projoy automatic dc isolation switch is installed). It’s possible that this emergency output is connected into the household electrical system in an improper manner which would result in backfeed.

I’ve read of several potentially poor implementations that believe they are mitigating all the risks of backfeed; but then later figure out that they are still sharing a neutral or PE route back to grid.

HotSwap

https://www.boards.ie/discussion/comment/121508853#Comment_121508853

Makes sense to put the warnings everywhere. It’s not like you don’t get enough stickers on the sheet.

HotSwap

https://www.boards.ie/discussion/comment/121508899#Comment_121508899

Dictionary definition of SHOULD. past tense of shall. [modal verb] 1. a — used to say or suggest that something is the proper, reasonable, or best thing to do.

graememk

https://www.boards.ie/discussion/comment/121509572#Comment_121509572

Yeah, still it's still not a must.

As for the emergency/backup output. If improperly connected, a fireman switch won't effect it as it will still be running from batteries.

Straight inverters don't have a backup output.

The fireman switch is not for anti-islanding. It is for disconnection of the panels.

I'd have one if I had everything in the attic.

Bluejohn1

Sorry if this is the wrong thread for this question. But I have an install going in as we speak. Got a quote/paid a deposit from *company A*. But an different company(*company B*) is doing the install. I assume they've have just been sub contracted and is fairly standard?

Mod:removed names

DrPhilG

I wouldn't be happy with the arrangement to be honest. You research your companies, get quotes, make an informed decision and then you end up getting someone else?

championc

https://www.boards.ie/discussion/comment/121510424#Comment_121510424

Get clarity immediately IN WRITING that the guys you PAID are the responsible party

bullit_dodger

https://www.boards.ie/discussion/comment/121509665#Comment_121509665

I'd be of the same opinion as Graeme here. If your getting a grant, they won't pass it without having a fireman's switch installed, but it's not an actual requirement I believe (if sans grant). Originally I thought it a waste of money, but for some houses who might have a long run of High voltage DC cables inside the house from the roof to where the inverter sits - it makes sense.

It's main function is to stop having those high voltage DC lines running "live" through the house when the main power is cut. That's why they specify "must be installed within 1.5m of where the wires enter the house". Nothing really to do with anti-islanding directly although it's a related insofar as the solenoid will break the connection to the inverter when the grid is cut, but yeah, a badly wired inverter back feeding the emergency power to the consumer unit and then out to the grid could happen with/without a firemans switch.

Aside: It's not a requirement in the north or the UK to have a fireman's switch.

Timmaay

How many kWh can you generally get out of a Solar battery? I've got a price on a 15kwp system with a 15kwh battery, I'm a dairyfarmer with a reasonably steady 90kwh daily load from say March to October and dropping back to 30 or 40kwh this time of the year. Main 2 times of the day I need power are at milking , 8 till 10am and 5 to 7pm, when I probably use 20kwh, and then other big draw is water heater using 250l a day which is ran off 2 3kw electric elements (which has proven horribly expensive last 2 yrs).

Anyways the above is the maximum size system the ESBN will let me get with my current MIC (16kva single phase supply that I wouldn't mind upgrading, but tidy grand on the solar system I've priced up and closing date soon), my aim is that I'll utilize most the solar I generate on the farm, and use the battery to supply a good part of the morning and evening peaks. How realistic is it to expect to charge the battery at night rate, and have a full 15kwh for the morning, then do the same again with daytime solar for the evening?

graememk

https://www.boards.ie/discussion/comment/121515097#Comment_121515097

You could safely push them to 15-10% of the advertised amount.

Should easily be able to charge on night rate, and no issue at all charging up again on solar for the evening.

What is the power draw of the plant when milking? The size of your hybrid inverter could limit how much can come from batteries. Can't say without getting specifics.

Re hot water.

How much do you use every day and what temperature would you normally heat to?

You possibly could look into an air source heatpump just to heat the water! Yes the outlay could be a few grand, for a 6kw one(same output as 2 immersions) but if your only heating to 50c it would be about a third of the running cost.(COP of 3), using 2kw instead of 6kw!

If the tank goes cold, you'll gain even more efficiency.

Rising main is say about 10c. You heat to 60.

Every time you empty that tank it's 15kWh.

Heatpump could heat it for 5. At a cop of 3.

This milder weather I'm heating a 500L buffer tank to 50 and getting 4x.

If you really want to get into the details, start a new thread!

Timmaay

2 5hp motors, and the load for them 2 or 3 hours would be 60amps or so.

With water, on average 250l a day to 60deg, I was actually only looking at a2w heat pumps the other day, they are actually surprisingly cheap and would be a no brainer with the cop of 3 or 4, however my biggest problem here is we have very hard water, that burns out elements regularly. A salt based water softener helps but I still only get 2yrs out of elements (using coated elements). What i read up was those a2w heat pump systems for say 2 or 3grand would only last afew years, so how short a life would they have with my hard water.

In terms of temperature, that's an interesting one. Ideally I'd have more control of temperature, at the minute all I can do is use a screwdriver to adjust the temperature on the element (which is factory set to 60deg), I remember once bumping it up to 70, and the water started coming out cloudy which probably meant it was burning the limescale in the water (or maybe Stripping the coating on the element or something?), so I decided to quickly drop back the temperature. 65 or 70degree water would be useful and would allow me to get away with less chemicals and/or less frequent hot washes for the milking machine, but obviously not worth wrecking elements or cylinders for.

I can run into milk quality problems if I don't hot wash frequently enough or temperature isn't high enough (which usually happens when one element burns out and the other one can't get all the water to temperature, which you might not spot till you have a problem), the fines for poor milk quality can run into the thousands so not something to mess with ha. However if I could find an a2w system that can sustain my water type, and gives me some better control on the temperature, and maybe say set it to run a 65 or 70degree wash once a week I'd be interested, but for now the simple solution is just stick with my 60degrees and throw in a new incoloy element every 2 or 3yrs.

Edit, just looking at the specs here, 5kw ac output for the inverter, so that's only 22amps of the 60amps that I'd use, I'm a long way off there so.

graememk

https://www.boards.ie/discussion/comment/121516114#Comment_121516114

1hp is 750w, which is 3.75, and I'm not sure if they are running completely flat out our not, but thats 7-8kw, which is 30-40 amps. With Immersions it would be 60!

What inverter(s) are you spec'd for by the way? with a 15kWp system would need an NC7 anyway, and that does allow export limitation. You could push it a bit further.

That is a lot of power, even for the FIT will help offset your bills somewhat! We're drystock, with some tillage, the crusher is our biggest load! Would you be using the whole tank for each milking?

As its not done and dusted, you possibly could look into something like a 8kW sunsynk, It has all the certs for ireland, just hard to get (have to import from the UK) It can do 8kW from batteries and can support a lot of solar panels. Still not the 60 amps but closer.

Hard water is killer on things, possibly need to up the capacity on that water softener!

As for the heat pumps, the hard water is something to keep in mind, But it wont have direct contact with the water, as it will heat your water tank though a coil in the water tank. But then that would be vulnerable to the same build up. And you cant replace that, Will have a longer lifespan than an immersion though. The hea tpump is on a sealed loop. I'd take advice from a local plumber whether you would even go as far as putting distilled water or solar panel fluid (glycol) in the sealed HP side and not use your hard water to protect it.

You could build some mitigation or "replaceability" into it and use a plate heat exchanger instead of a internal coil to heat the water in the tank, and when that starts to give up, you could replace it, But does mean an extra pump but that setup is fairly trivial.

I have a EcoForest ecoAir 3-12kw heat pump, It can heat Hot water to 75c if you want it to, COP would could be down to 2 at that point though, but that would be only for the last 15c though.

When running at about 40-50c it can output 12kW (of heat) but pushing it higher it drops back to 10ish kW. It is an R290 heat pump which does better at higher temperatures.

(possibly you could upgrade to a 500L tank, and heat it all on night rate!)

The devils

 devils1:09 pm

Has anybody used one of these and are they easy to set up ?

OpenDTU CMT - Your evaluation for your balcony solar system compatible to Hoymiles HMS and HMT series (CMT module

10-10-20

https://www.boards.ie/discussion/comment/121694972#Comment_121694972

Funnily enough, yes. :)

All you need is the serial number off the inverters and then the openDTU esp32 with the modem. Then its easy enough to get it connected to Home Assistant, or just use it as a standalone monitor (limited functionality as a standalone unit though). Where on that path are you?

The devils

https://www.boards.ie/discussion/comment/121695028#Comment_121695028

20240127_170408.jpg

Cheers fella.

Thar dtu will come inhandy fur sure. For the time being I'm using a Knight socket monitor. 2 panels up and hopefully get the other 2 up by the weekend. Hard the weekend with the wind 🤣

Small addition compared to some of the recent pics.

Got HA working - juat haven't had the time to go back to it though.

I might move 3 of the 12 panels from the east from the house onto shed also (later in the spring)

Apart from that all good 👍

10-10-20

https://www.boards.ie/discussion/comment/121695508#Comment_121695508

Bravery award for this punter! :)

What slope is your roof? Mine is 35 degrees... no way I'm mounting that myself.

The devils

20240130_164858.jpg

https://www.boards.ie/discussion/comment/121695572#Comment_121695572

🤣🤣 it got a little scary when I had to remove the first panels clamps and see tue other one slide about 6 inches on me. I'd say my roof is about the same as you. The house is roughly 45 degrees (dormer)

I took some painkillers for my back and half a packet of plasters for my hands-struggled getting the tiles off. Bit of fun...

Cheers

Was home before it got home dark and got the third one up

The devils

N/A

Hellrazer

Heres a quick question - Is North East a complete waste of time. - sat here this morning at around 8.20 and the sun was splitting the trees and I was thinking I could get 6 or even 8 panels on my extension - DIY of course - shame to waste that early morning sun.

Heres my question. If I DIY the panels could you have a second inverter installed? Can I just run the DC to a second inverter and have a sparks run a feed to the consumer unit?

Im thinking of buying 6 x400 watt panels and a 4kw inverter which would bring me to 7kw.

Other problem Im concerned about is the NC6 but since they wont be generating at the same time would this be an issue?