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Solar PV Hints, Tips & Troubleshooting

DrPhilG

Well I've reached the point of driving everyone nuts on the PV quotes thread, and since I now have my system installed and running my endless questions no longer belong there.

So I figured I'd ask here, and also provide a home for others in the same boat, with general questions and advice on managing post-install.

My first question (of many) is how do people best manage their production in order to reduce grid export? Despite being overcast and miserable a fair bit of the day, I've produced 24kWh so far today, but ended up exporting 11.

Not too bad when we're home, as the wife did a few loads of washing and drying, put on the dishwasher etc.

But we're both at work tomorrow so other than a timed or remotely activated washer/dryer run we would end up exporting a lot more.

Extra battery capacity or a water diverter would help, but they don't tend to justify their costs in the long term.

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DrPhilG

mp3guy wrote: »

2. Depends on the inverter, my one can pick up the extra energy from a second inverter via the same shared meter mechanism that is used to control the export limit.

So your second inverter essentially reads the overall export, and then charges the battery accordingly?

DrPhilG

garo wrote: »

With your dual inverter setup it may be better to go for an AC battery setup with it's own dedicated battery inverter. You can then buy two non-hybrid inverters - which are much cheaper - and flog your hybrid inverter off. Yes you may lose a small bit of efficiency but it will give you a lot more flexibility

This thought crossed my mind too. Is that the reason that hybrids are so common, because they are more efficient due to storing on the DC side?

I've now got 20kWh of LiFePo4 batteries winging their way from China so I've got a few months to figure out the rest.

Once I have the new batteries sorted, I'll be selling the PylonTech to recover some of the cost. Even second hand they tend to sell very high.

I could probably get a pretty solid price for the Solis 5kw that I have too, so any suggestions for different brands in a non hybrid version?

garo

You could get a Solis non-hybrid too. https://solartricity.ie/inverter-solis-single-6-0kw/ 6kW dual MPPT for 650 before VAT. The equivalent hybrid is twice the cost: https://solartricity.ie/inverter-solis-hybrid-6kw/

I think hybrid's aren't popular due to efficiency - my guess is the difference is less than 5% when charging the battery possibly much less - but that you get everything in a single box. It saves on space/install costs etc. Also one less thing to go wrong/need maintenance.If you have a single PV inverter plus single battery inverter you don't save much over a hybrid. But as in your case you have two inverters it might make sense to go for a separate battery inverter.

Just note that you'll have three inverters - two PV plus one battery - reading your grid import/export. There is a tiny risk of them not agreeing on what the export is and working cross purposes but with appropriate margins you should be able to sort it out.

PS: I *may* be interested in one of your pylontechs but with the incoming FiT you'll probably get a better price from someone else less concerned about payback. But it you are stuck and need to shift, let me know.

slave1

You went and ordered them! solar can be a bit of an obsession alright.
You should be able to shift the PylonTechs no hassle, how many will you have and how much you thinking, the brother has two and thinking of expanding?

E30M3

DrPhilG wrote: »

This thought crossed my mind too. Is that the reason that hybrids are so common, because they are more efficient due to storing on the DC side?

I've now got 20kWh of LiFePo4 batteries winging their way from China so I've got a few months to figure out the rest.

Once I have the new batteries sorted, I'll be selling the PylonTech to recover some of the cost. Even second hand they tend to sell very high.

I could probably get a pretty solid price for the Solis 5kw that I have too, so any suggestions for different brands in a non hybrid version?

How much do the Pylontechs sell for second hand? I see another poster quoted a price of 3,100 total for 9.6 or 4 batteries which seems competitive

mp3guy

garo wrote: »

With your dual inverter setup it may be better to go for an AC battery setup with it's own dedicated battery inverter. You can then buy two non-hybrid inverters - which are much cheaper - and flog your hybrid inverter off. Yes you may lose a small bit of efficiency but it will give you a lot more flexibility.

Sounds like a worse setup to be honest. One more device to have trouble with plus all associated installation works, space usage etc... Plus, if your battery storage is behind an inverter not connected to your PV, you have little flexibility when it comes to back up power, if this is something that interests you. You can't charge your batteries if the grid is down for example. Depending on the inverter it may not even support any back up feed at all.

DrPhilG wrote: »

So your second inverter essentially reads the overall export, and then charges the battery accordingly?

Yes.

garo

I disagree. Both have their advantages and disadantages. I mentioned the extra install/space already. If you are going for a two inverter setup getting 2 non-hybrid inverters plus one battery will be several hundreds cheaper than 2 hybrid inverters. I wouldn't recommend it for a small set up but if you are getting multiple inverters it is certainly worth exploring.

mp3guy

garo wrote: »

I disagree. Both have their advantages and disadantages. I mentioned the extra install/space already. If you are going for a two inverter setup getting 2 non-hybrid inverters plus one battery will be several hundreds cheaper than 2 hybrid inverters. I wouldn't recommend it for a small set up but if you are getting multiple inverters it is certainly worth exploring.

What about one hybrid plus one non-hybrid? That's what I have (and was suggesting) and it works perfectly. All the functionality of your suggested three inverter setup, with less complexity and space and even more features. Price difference? I suspect not much.

graememk

mp3guy wrote: »

What about one hybrid plus one non-hybrid? That's what I have (and was suggesting) and it works perfectly. All the functionality of your suggested three inverter setup, with less complexity and space and even more features. Price difference? I suspect not much.

Yours is solax aren't they?

I know they are more expensive but the batteries are high voltage, so less losses, and also I'd say can discharge at about 5kw too?

mp3guy

graememk wrote: »

Yours is solax aren't they?

I know they are more expensive but the batteries are high voltage, so less losses, and also I'd say can discharge at about 5kw too?

Yes that's right https://www.solaxpower.com/wp-content/uploads/2020/02/Battery-Triple-power-white.pdf. I have two so I get double the rated charge/discharge. You can stack up to four but it maxes out at around the 20A mark.

garo

mp3guy wrote: »

What about one hybrid plus one non-hybrid? That's what I have (and was suggesting) and it works perfectly. All the functionality of your suggested three inverter setup, with less complexity and space and even more features. Price difference? I suspect not much.

Yeah that would be a good option too.

DrPhilG

Yeah since I already have a Solis hybrid then I could presumably leave the batteries connected to that and just add another non-hybrid to handle the additional cells.

And wreck mp3guy's head about his system to make sure I can divert one inverters excess to the hybrid's battery.

championc

DrPhilG wrote: »

Single phase Solis inverters cannot be paralleled it seems.

Not exactly. I tried to explain this before. You would have two inverters normally connected into separate MCB's and they would then be connected onto you main mains busbar.

What I was suggesting is that you take these two and Y them into one other MCB before connecting off to the main mains busbar. So the idea is then to measure the TOTAL output of both to then have an ME3000 gobble up all of the excess from both inverters.

If your desired load exceeds an ME3000 3kw, you could keep the existing hybrid and add a 48v string of batteries to it too.

DrPhilG

championc wrote: »

Not exactly. I tried to explain this before. You would have two inverters normally connected into separate MCB's and they would then be connected onto you main mains busbar.

What I was suggesting is that you take these two and Y them into one other MCB before connecting off to the main mains busbar. So the idea is then to measure the TOTAL output of both to then have an ME3000 gobble up all of the excess from both inverters.

If your desired load exceeds an ME3000 3kw, you could keep the existing hybrid and add a 48v string of batteries to it too.

I think that's what graememk just suggested on the battery thread. I think I get you now. It was Solis who told me you can't connect the 2 Solis. Not sure why I keep paying them any heed...

So although the 2 would technically not be linked to each other, they would be both feeding into the same line and then the Sofar would scoop the export from that line and charge the battery?

And since I'm not needing an additional solar inverter yet (until I increase capacity), I would only need to add the Sofar plus batteries for now.

championc

DrPhilG wrote: »

So although the 2 would technically not be linked to each other, they would be both feeding into the same line and then the Sofar would scoop the export from that line and charge the battery?

And since I'm not needing an additional solar inverter yet (until I increase capacity), I would only need to add the Sofar plus batteries for now.

Correct and correct

DrPhilG

championc wrote: »

Correct and correct

Slowly but surely, I'm learning...

buzz11

I'm just planning my 7 panel self-install and here is my cable entry point.

I'm hoping to find a sheath that will go cover the cable to prevent chaffing...open to suggestions

championc

buzz11 wrote: »

I'm just planning my 7 panel self-install and here is my cable entry point.

I'm hoping to find a sheath that will go cover the cable to prevent chaffing...open to suggestions

Why do you feel it would move and chaffe ? Maybe just a good dollop of mastic / silicon sealant. I'm assuming that that is coming out under where your first or last panel will be.

MAULBROOK

championc wrote: »

Why do you feel it would move and chaffe ? Maybe just a good dollop of mastic / silicon sealant. I'm assuming that that is coming out under where your first or last panel will be.

That's cowboy stuff, its meant to be up there for 20 to 30 years and a lump of silicone is not going to cut it.

daughy

So I set up a new channel on the app telegram, as a way for people to instantaneously write to eachother and give ideas, pictures, videos of your solar ideas.
You can hide your phone number on the app for security purposes.
The link to the channel in the telegram search is
solar power ireland

slave1

Quirky item from AMZ, €22 delivered, 12 Volts 10 Watts Portable Power Solar Panel Battery Charger

unkel

Or buy it from China for about a fiver

(hint: don't - these yokes are rubbish)

tails_naf

I just checked my electricity bill, and after getting solar in last November, the bill is as high as ever, if not a bit higher, and kWh usage on the bill, not estimated, was also high. I checked the meter itself when I was exporting power and I saw the led flashing. Would this be expected, thst the 1000 imp/kwh led would flash when exporting? I would have assumed it would be import only.

KCross

tails_naf wrote: »

I just checked my electricity bill, and after getting solar in last November, the bill is as high as ever....

You wouldnt have had much generated since November to make much difference to your bill.

Do you have the total kWh figure from your inverter that it has generated since it was put in.... easy to calculate then what effect it had on your bill.

The fact your bill went up just means you used more!

SD_DRACULA

Guys what are the max power solar panels out there for dimensions 1650x1000 (or less) so far found some at 375w.
Also if I have two strings of 8 panels each and one of the strings gets a bit of shading from a chimney, will it bring down the other string without optimizer or just the string where the shading happens?

championc

tails_naf wrote: »

I just checked my electricity bill, and after getting solar in last November, the bill is as high as ever, if not a bit higher, and kWh usage on the bill, not estimated, was also high. I checked the meter itself when I was exporting power and I saw the led flashing. Would this be expected, thst the 1000 imp/kwh led would flash when exporting? I would have assumed it would be import only.

How many panels have you installed / what's the total installed kWp ? Have you a battery ?
You should have 4 full months worth of data, which should be loads and should make some difference to your bills. However, if you have no battery and if there was maybe nobody at home during the hours of generation, then the savings would not be huge.

As for the meter, look at the meter on an hour and look at the figures an hour or two later.

SD_DRACULA wrote: »

Also if I have two strings of 8 panels each and one of the strings gets a bit of shading from a chimney, will it bring down the other string without optimizer or just the string where the shading happens?

Only the whole string with any shading on it will be affected. And yes, if only one panel in a string of 8 gets even an eighth shaded, the whole output of THAT STRING will plummet

MAULBROOK

Its no deal barker, couple of optimizers would be very cheap.

gomamochi1

SD_DRACULA wrote: »

Guys what are the max power solar panels out there for dimensions 1650x1000 (or less) so far found some at 375w.
Also if I have two strings of 8 panels each and one of the strings gets a bit of shading from a chimney, will it bring down the other string without optimizer or just the string where the shading happens?

Optimisers on the shaded panels. Request that in your quote

MAULBROOK

gomamochi1 wrote: »

Optimisers on the shaded panels. Request that in your quote

I doubt the quote would change at all. but as you say make sure its part of the works.

jkforde

Apologies for my ignorance and if this has been covered many times elsewhere but boards search functionality is cat. \
I've a new 6.7kW solar up and running (future BEV proofing) and still have the rotating disk 24hr meter.... since I am not consuming the majority at the moment (diverter, battery & BEV imminent

), is the surplus being dumped into the grid? (have observed the disc stops rotating)