Solar Power Expert Needed

MikeM3 · Oct 9, 2023

I am a retired Electrician and started looking at Solar Power, (Black Magic to me),
after much reading of "How To", I decided to build myself a system, bat as I don't
have a roof, I live in a ground flat, I decided to build a portable unit, I get the sun
in the living room in the morning and in the kitchen in the afternoon.

The unit that I have built has 6 X 1,000 watt panels, 2 X 130 AH leisure Batteries
and a 3Kw/6Kw peak, pure sine wave inverter, it all works very well, so far.

I would like to double the output, to 6Kw or more, my initial idea was to buy a second
inverter of the same make and size as the one that I have and parallel them, but I was
advised against it, by the supplier as they would not be compatible!

Having read more on the subject I find that some inverters are incompatible, because
of the design, I cannot find out what that is.

The question is, have any of you here managed to overcome this seemingly crazy bit
of design and managed to parallel two such units?

I am thinking that equalising/balancing transformers, one for each, would fix this, any
ideas?

The inverter that I have has no earth!

Mike.

[ElectriciansForums.net] Solar Power Expert Needed

newfutile · Oct 9, 2023

6 x 1000 watt panels without a roof ,are these in the garden? Where do you get 1000 watt solar panels from? The trouble with inverters is they have to up the mains voltage to feed back if this is a grid tied system , if it’s not then you can’t ensure the phase angle is the same which will most likely burn both devices up, you may be able to add a grid tie inverter ,this would synch the waveform

MikeM3 · Oct 9, 2023

Thank you for the reply Newfutile, here is a picture of the panels, I got them from China, they
are quite a recent thing.
I have been reading more about paralleling inverters and unless they are built to do so, it is
impossible, they must be the same design and manufacture, then on is designated the lead
and calls for the second when needed, I think that there has to be some sophisticated wiring
installed, if I find any I will put the information here, for to see and learn.

Mike.

newfutile · Oct 10, 2023

Is there a rating label on the back I have a deep distrust of Chinese claims on solar and many other things they sell

timhoward · Oct 10, 2023

Can we assume that this is an entirely off-grid setup?

MikeM3 · Oct 10, 2023

There is no rating label, newfutile, but they work, I will have
the system up and running permanently, I hope, in the next
few days, I have bought a bigger inverter.

Yes, timhoward, this is an off-grid system.

Mike.

newfutile · Oct 10, 2023

I don’t doubt that they work but a 1000 watt panel of 20% efficiency would have to be 5 metres squared (based on solar irradiance of 1000 W/ sqM.

how much current does your charge controller report they are giving and at what voltage?

HappyHippyDad · Oct 10, 2023

No relevant knowledge from me @MikeM3 , I just thought I'd say 'how exciting!'

Actually, I'll add a little.

Make sure you look after the batteries, i.e keep them topped up (unless they are sealed). I put a panel on my shed, all worked well for a couple of years until I realised I had let the electrolyte level run too low and the battery was beyond repair. I suspect you're fully on the ball with this though, along with all the other interesting maths... Days of autonomy, angle of panel etc.

The earthing is an interesting one. Will you have an earth on your system at all and use an RCD or are you completely isolating the earth?

Good luck with your venture

oscar21 · Oct 10, 2023

Do solar panels work through glass?

Gary K · Oct 10, 2023

My Sunnyboy device that monitors the output of my panels and connects to the inverter via Blutooth is self charging with its own solar panels built in and it sits on the windowsill inside and that seem to manage OK.