Another 'why is my set up not doing what it said on the tin' thing

[winmoz]

I have a home office at the bottom of the garden (located in Berkshire)
Cold in the winter (8-10c) and hot in the summer (30-32c) despite building reg spec insulation.
I have just installed 4x300W Photnic Universe panels, an Iconica 3000w hybrid inverter and 6 x 120AH AGMs with a view to powering some heating and cooling, as well as having the ability to keep some lights on if there are power shortages over the coming months.
The panels are on a flat(ish) roof and not overshadowed - I may be able to tilt them a little to the south, but currently (in November) the best power I've seen is 90w. The panels tend to provide 34v with, so far a max current of 2A.

I know it's winter and that the headline 300W is in lab conditions, but have I got some faults somewhere?

 

[ProDave]

I looked into an off grid supply to try and power all the "always on" stuff, it would have been less than 100W but on 24/7/365

I rapidly drew the conclusion that any system would have to be massively over sized to produce anything useful in winter, in which case much of the summer generation would be wasted, or if sized for the summer would be totally inadequate in winter.

The only viable solution is just grid tied solar, then it should be easy to self use all you generate at any time of year.

 

[binky]

What's the start up voltage for the inverter?

 

[Joules]

Yes, like many thousands of folk, I have taken the plunge and started on the path of really being very interested in the amount of solar radiation I can capture and convert into fast moving electrons.
I'll apologise up front as I'm a marketer by trader, so I should have realised that a 300W panel does't mean a 300w panel and that size really does matter when it comes to battery arays!

Solar radiation is called ‘Insolation’ and its unit of measure is in Watts per square metre or W/m2. Solar panel ratings are set at an insolation value of 1000 W/m2 and efficiency is the based on the area of the panel exposed to sunlight not the dimensions of the panel itself. Physics dictate the efficiency of generation and the theoretical limit is around 30% the best achievable in the market place is around 22%. You can purchase insolation meters to measure the strength of sunlight at any given moment.

Advice: don’t do an install yourself rather use an accredited installer or if you must do it yourself first obtain DNO approval in order to obtain SEG payments through a smart meter. As for self-consumption your GTI allows this under appropriate foreign regulations, for example the Philippines however UK G98 regulation do not accommodate zero-export and the GTI manufacturer will not tell or help you setup or wire the inverter for self-consumption zero-export in the UK.

As for funding your install, many will talk about pay back especially if SEG is involved. You can get around the lack of pay back by saying the cost of install is a lifestyle change no different to that of changing your car.

Moved from "introduce yourself" to avoid 2 topics same subject

 

[winmoz]

Hi, it’s not going anywhere need the meter. This is an off grid install designed to give some optionality to powering my office.
The hybrid inverter can be plugged into the mains via a 3pin to give access to charging and load handling if desired, but selling generated power or offsetting bills is not a project objective.


Moved from "introduce yourself" to avoid 2 topics same subject

 

[winmoz]

Not sure what you are referring to - sorry. Inverter is set to switch over from solar to utility when the battery voltage drops below 24.5v
I am not sure what the voltage is when the unit is switched from standby to on (I do this manually)

 

[binky]

How have you wired the panels, 4 in a single string, 4 in parallel or what?

Your inverter needs 80v, if I'm looking at the right one, to start up. Your panels are 30v so 3 or more in a single string should get the ' show on the road '. If you have wired it as 2 lots of 2 panels in parallel, with then it will struggle to get the inverter working at all as you will be presenting only 60v.

 

[bladerunnerpv]

Not sure what you are referring to - sorry. Inverter is set to switch over from solar to utility when the battery voltage drops below 24.5v
I am not sure what the voltage is when the unit is switched from standby to on (I do this manually)

Think this is Binky's question... the inverter spec should quote a "startup voltage", which is how many volts input does it need before it starts giving any output.
Ha, I see Binky's just beaten me to it!

 

[winmoz]

Ah, thanks both. The set up is 2 parallel groups of 2 panels in series.

When I take the Iconica hybrid inverter out of stand by it reports 84 volts briefly before settling down to a running range of 31-44 volts currently.

The set up was recommended by photonic universe here :

 

[winmoz]

Only difference is I am using 300W panels and 120ah batteries

 

[binky]

84 volts is just enough to get going, I would try it as 4 panels as a single string, provided the inverter can take the higher voltage.

 

[Joules]

Hi, it’s not going anywhere need the meter. This is an off grid install designed to give some optionality to powering my office.
The hybrid inverter can be plugged into the mains via a 3pin to give access to charging and load handling if desired, but selling generated power or offsetting bills is not a project objective.


Moved from "introduce yourself" to avoid 2 topics same subject

Okay! Your inverter is acting as a household appliance.

Next thing is make sure that you are safe so earthing needs to be considered.
You need to get a competant person registered electrician involved to advise you about this.
A difficulty you have is that when you unplug the inverter you loose the protective earth (PE) that your house is providing so your electrician may need to wire your office mains supply in a TT arrangement with a ground spike. The ground spike would connect to the earth bar in a small consumer unit and your inverter would need a permanent earth connection to it. Your office 13A sockets will be connected to the this consumer unit.

1. Is your house protected by 30mA RCD in your consumer unit?
2. Where does your mains supply to office come from, a ring main or a radial directly from your consumer unit?

 

[Joules]

How have you wired the panels, 4 in a single string, 4 in parallel or what?

Your inverter needs 80v, if I'm looking at the right one, to start up. Your panels are 30v so 3 or more in a single string should get the ' show on the road '. If you have wired it as 2 lots of 2 panels in parallel, with then it will struggle to get the inverter working at all as you will be presenting only 60v.

The OP has not said whether he bought the MPPT or PWM version.

 

[binky]

The OP has not said whether he bought the MPPT or PWM version.

true, would be nice if he posted the data sheet / manual.

 

[Joules]

true, would be nice if he posted the data sheet / manual.

Eyeballed the manual not seen the datasheet. Need to see the OEM declaration about inverter topology. If it had been a GTI then the declaration would have said whether there was a galvanic connection between AC and DC sides giving rise to a continuous DC leakage current. Regulation requires a Type B be fitted as a precaution however where there is isolation through transformers then no RCD would be required.

But how does all of this relate to the inverters output? This should feed a small distribution board with a Type A 30 mA RCD? As to the RCD required on the Inverters input what mA size is required. If the OP is using a house consumer unit protected by RCD it is likely to be Type A 30 mA. The declaration normally describes the Type and mA size which can be 100mA or 300mA depending on the make of inverter.

 

[binky]

Eyeballed the manual not seen the datasheet. Need to see the OEM declaration about inverter topology. If it had been a GTI then the declaration would have said whether there was a galvanic connection between AC and DC sides giving rise to a continuous DC leakage current. Regulation requires a Type B be fitted as a precaution however where there is isolation through transformers then no RCD would be required.

But how does all of this relate to the inverters output? This should feed a small distribution board with a Type A 30 mA RCD? As to the RCD required on the Inverters input what mA size is required. If the OP is using a house consumer unit protected by RCD it is likely to be Type A 30 mA. The declaration normally describes the Type and mA size which can be 100mA or 300mA depending on the make of inverter.

He's off-grid. Most inverters have some form of RCD protection built in, but I'm not familiar with this make, so an additional RCD might be wise

 

[Joules]

John Ward who owns Flameport Electrical in Dorset has a YouTube channel that explains issues regarding electrical supplies to out buildings. He provides some helpful videos:

Earthing Systems for Outbuildings

Earth Electrodes Part 1

Earth Electrodes Part 2 - Installing, Loop Impedance Testing

Earth Electrodes Part 3 - 3 Wire Testing Example

He provides options on earthing and the use of ground spikes. The earth impedance tester he uses retails around £1200. Your electrician may have a similar instrument if not the same one.

 

[binky]

Ah, thanks both. The set up is 2 parallel groups of 2 panels in series.

When I take the Iconica hybrid inverter out of stand by it reports 84 volts briefly before settling down to a running range of 31-44 volts currently.

The set up was recommended by photonic universe here :
View attachment 14450

Diagram doesn't show any earthing, have you any sort of earthing connected to the system?