Solar PV Hints, Tips & Troubleshooting

garo · 21-10-2020 11:14pm

Exactly which is why I give such a wide range of 5-10c and qualify my statement with probably. If you are Unkel you probably got your battery for free do you can use and abuse it all you want! But if you paid list price for the battery and want the capacity to not deteriorate significantly for 10 years you may want to go easy on the night charging. But as always do your sums and know there is a wide range of outcomes in terms of battery life.

unkel · 21-10-2020 11:24pm

I think a main consideration not many people make is that even with an SEAI installed system, the inverter costs more than the battery. Batteries are relatively cheap these days. Hybrid inverters are still horribly expensive. And they will fail.

Hybrid inverter about EUR1300 + VAT retail
2.4kWh Pylontech battery EUR900 + VAT retail

And you can replace the latter yourself with one made from similar cells for less than half that. People worry too much about batteries! If you went to the expense of getting one, bloody use it and let it pay for itself before the rest of the system fails LOL!

WhoamI2022 · 22-10-2020 12:32pm

From other thread

Looking for some advice, have a GivEnergy system. I have tried to change the mode but it keeps going back to Mode 1 by default, no matter what I do, does everyone else have the same issue? have logged a call

garo · 22-10-2020 1:32pm

unkel wrote: »

I think a main consideration not many people make is that even with an SEAI installed system, the inverter costs more than the battery. Batteries are relatively cheap these days. Hybrid inverters are still horribly expensive. And they will fail.

Hybrid inverter about EUR1300 + VAT retail
2.4kWh Pylontech battery EUR900 + VAT retail

And you can replace the latter yourself with one made from similar cells for less than half that. People worry too much about batteries! If you went to the expense of getting one, bloody use it and let it pay for itself before the rest of the system fails LOL!

Damn it! I took your advice and charged it to 90% last night and this morning in the bright sunshine ended up exporting. Will have to cap the charge at 70% for now. But it worked beautifully - can do it from the phone app - and had the added advantage of charging my battery at the full rate and not the current-limiting on charge that I had started seeing on my battery due to low temps and low charge levels.

garo · 22-10-2020 2:11pm

WhoamI2022 wrote: »

From other thread

Looking for some advice, have a GivEnergy system. I have tried to change the mode but it keeps going back to Mode 1 by default, no matter what I do, does everyone else have the same issue? have logged a call

There's a dedicated Givenergy thread. You'll probably get a better response there.

22-10-2020 3:34pm

garo wrote: »

The battery has a finite number of cycles (6k-10k) s

I'd love to see some real evidence to back that up.

garo · 22-10-2020 3:46pm

Sir Liamalot wrote: »

I'd love to see some real evidence to back that up.

https://uwspace.uwaterloo.ca/bitstream/handle/10012/12177/Catton_John.pdf?sequence=3&isAllowed=y

22-10-2020 3:53pm

"Thus, lifetime prediction models are developed in order to better understand the design and operational consequences on performance degradation of Li-ion batteries."

That's conjecture not evidence.

garo · 22-10-2020 4:01pm

Thought you might say that. This is a bit better:
https://iopscience.iop.org/article/10.1149/1945-7111/abae37

DrPhilG · 22-10-2020 4:17pm

garo wrote: »

Damn it! I took your advice and charged it to 90% last night and this morning in the bright sunshine ended up exporting. Will have to cap the charge at 70% for now. But it worked beautifully - can do it from the phone app - and had the added advantage of charging my battery at the full rate and not the current-limiting on charge that I had started seeing on my battery due to low temps and low charge levels.

Which inverter/battery do you have?

I'm going to set it to not discharge overnight, and start night time charging for the next few months.

22-10-2020 4:29pm

garo wrote: »

Thought you might say that. This is a bit better:
https://iopscience.iop.org/article/10.1149/1945-7111/abae37

That's closer to the mark...

"A round of cycling for each cell varied from 125 to 1000 cycles, depending on the rate of degradation at the specific test conditions. .....the study was considered complete once a cell reached 80% of its initial capacity."

6k was it?

"Therefore, for each cell, the total capacity throughput was divided by the nominal capacity to get the total equivalent full cycle count."

Still modelling, not comprehensive testing. Besides a lab doesn't factor age, temperature variations or real world use.

" EFC is extrapolated based on the present degradation rate for those cells." .....yawn.

PS I can do the same with traction lead.

unkel · 22-10-2020 5:55pm

garo wrote: »

Damn it! I took your advice and charged it to 90% last night and this morning in the bright sunshine ended up exporting. Will have to cap the charge at 70% for now. But it worked beautifully - can do it from the phone app - and had the added advantage of charging my battery at the full rate and not the current-limiting on charge that I had started seeing on my battery due to low temps and low charge levels.

If you have a substantial East facing array and your consumption is not as high as mine, then I certainly wouldn't charge it to 90%. In my case there is no chance of exporting to the grid in the morning unfortunately

garo · 22-10-2020 7:56pm

DrPhilG wrote: »

Which inverter/battery do you have?

I'm going to set it to not discharge overnight, and start night time charging for the next few months.

I have a Growatt SPH3000 and a Pylontech US2000plus.

unkel wrote: »

If you have a substantial East facing array and your consumption is not as high as mine, then I certainly wouldn't charge it to 90%. In my case there is no chance of exporting to the grid in the morning unfortunately

Right I forgot you are W facing. I'm 50/50 E/W. I've set it to 70 for now but looking at tomorrow's forecast 50 might be better. It's promising to be a good one here in Dublin.

garo · 22-10-2020 8:01pm

Sir Liamalot wrote: »

6k was it?

Was on my lunch break so couldn't respond properly.

Sir Liamalot wrote: »

"Therefore, for each cell, the total capacity throughput was divided by the nominal capacity to get the total equivalent full cycle count."

Still modelling, not comprehensive testing. Besides a lab doesn't factor age, temperature variations or real world use.

I think you misunderstand this as they discharge to different DoD and convert to Equivalent Full Cycle to compare like for like. So a 100->50 cycle is worth hald a 100->0 cycle.

As regards age and temperature, the paper linked first has real world number at 25 and 60C for storage from 1 to 6 months.

Sir Liamalot wrote: »

" EFC is extrapolated based on the present degradation rate for those cells." .....yawn.

Yeah I agree that's not a full test. But which side are you on? Do you think 6k-10k is an overestimate or underestimate?

I'm going to go dig for some more research papers.

22-10-2020 8:28pm

garo wrote: »

But which side are you on? Do you think 6k-10k is an overestimate or underestimate?

I'm going to go dig for some more research papers.

Vastly over. Unproven. Marketing figure.
And OPzS Lead can generate the same on paper figures. They're about 8-10 times cheaper.

Keep digging I've been looking since before Elon Musk launched Neo-Tesla.

garo · 22-10-2020 10:00pm

Now Sir Liam I don't thin you are being very fair. Read that second paper carefully. It's a good one. For EFC:

In this work, one EFC is based on the nominal capacity of the cell. Therefore, for each cell, the total capacity throughput was divided by the nominal capacity to get the total equivalent full cycle count.

For LFP they say:

The LFP cells exhibit substantially longer cycle life spans under the examined conditions: 2500 to 9000 EFC vs 250 to 1500 EFC for NCA cells and 200 to 2500 EFC for NMC cells. Most of the LFP cells had not reached 80% capacity by the conclusion of this study for the NCA and NMC cells, and their longer-term degradation will be reported in a later work

However, they did test LFP cells to 3000 full cycle equivalent and most of them retained 90% capacity. Those that didn't were operating at higher temperatures or 3C discharge rates. Look at figure 3 in particular. I would say that extrapolating from 3000 full cycles is not a terrible reach. A "round" of cycling was 125-1000 cycles but they did multiple rounds. So some of their tests went to 4000 effective full cycles.

22-10-2020 10:23pm

Just for arguments sake these are ~8 times cheaper.

1500 cycles to 80% DOD to 80% rated capacity.

22-10-2020 10:25pm

A lot depends on how you use them. Phone batteries last a year generally for instance.

garo · 22-10-2020 11:13pm

Mine has lasted four and is still at 82% health.

You are changing the topic though. Reading that paper we see real life experiments which show > 90% capacity after 3k cycles. 6k for 80% DoD isn't likely to be a vast overestimate like you claimed.

unkel · 23-10-2020 12:05am

And remember all those "facts" on spec sheets are the number of full cycles to 80% capacity. This could be 7000 (which is about 25 years) but the battery will still be fine, just degrading further. You could very well get 50 years and still be at 50% capacity

Per spec sheet cycle / per kWh LiFePo4 have been cheaper than lead acids for several years now and of course they are getting cheaper. Lead acid isn't

That said, I wouldn't buy either at market values but if you get them dirt cheap or free, you are laughing

23-10-2020 12:08am

garo wrote: »

You are changing the topic though. Reading that paper we see real life experiments which show > 90% capacity after 3k cycles. 6k for 80% DoD isn't likely to be a vast overestimate like you claimed.

Sure I was. Same as I've no idea how you made that leap of faith.

23-10-2020 12:13am

unkel wrote: »

Per spec sheet cycle / per kWh LiFePo4 have been cheaper than lead acids for several years now and of course they are getting cheaper. Lead acid isn't

Per spec sheet it's not because cost per kWh extracted ought outlast the lifetime of a lottov installations so the on paper figures of LiFePO4 if they are true are redundant (lead's still looots cheaper) because we'll never see the end of them.

However; my tool, laptop and phone batteries don't last, If I wasn't such a cynic I'd wonder why.

unkel · 23-10-2020 12:25am

Sir Liamalot wrote: »

Per spec sheet it's not because cost per kWh extracted ought outlast the lifetime of a lottov installations

Haha, yes this is true. I can imagine the people having had "cheap" battery installs done courtesy of the very generous tax payer and then a few years in (just outside of warranty) their ridiculously expensive hybrid inverter fails and they get a quote of €2k to get it replaced :eek:

23-10-2020 12:34am

Funny thing is you can make inverters last 15 years. They're the only kind I buy.

Yet we don't. Then we callit green.

My latest addition to the fleet is 12 years old.

20 year old design mind...and still beating the new kids on the block.

Newer's cheaper...not better.

gomamochi1 · 23-10-2020 11:23am

Have a complication with my setup would appreciate help= the eddi is draining battery power this morning at 8am from the Solis hybrid inverter charged 4.8kw batteries when there was no sun out. The eddi reads like there was 2.2kw solar gain but in fact it was draining from my battery which I have started charging on night rate meter. I thought I had set up solis inverter to only discharge batteries from 2PM to 8PM daily. Not sure why this is happening. Thanks for the help. See below screenshots of myenergie hub and solis inverter hub.

DrPhilG · 23-10-2020 11:39am

gomamochi1 wrote: »

Have a complication with my setup would appreciate help= the eddi is draining battery power this morning at 8am from the Solis hybrid inverter charged 4.8kw batteries when there was no sun out. The eddi reads like there was 2.2kw solar gain but in fact it was draining from my battery which I have started charging on night rate meter. I thought I had set up solis inverter to only discharge batteries from 2PM to 8PM daily. Not sure why this is happening. Thanks for the help. See below screenshots of myenergie hub and solis inverter hub.

If you go into the Eddi icon on the myenergi app and check the total power used, does it still give you a high figure? In the consumption history?

The myenergi app does sometimes throw up odd numbers but 5 minutes later they're settled. Like in my screenshot you can see a few little wobbles around 10am, but the total consumed is still 0kWh.

If your consumption history shows that you DID actually consume a large amount then I'd contact myenergi support. Their phone support is very good in fairness.

daughy · 23-10-2020 12:20pm

I'm no expert at the moment with the Eddie, but if you have the ct clamp connected to the live battery, and connected to the Harvi ct3 for instance, is there not an option on the Eddie to configure the ct3 connected live battery to avoid drain? I have my grid ct on ct1, my solar on ct2, and if in the future a zappi or batteries connected to ct3.

daughy · 23-10-2020 12:27pm

This should help i hope with the avoid battery drain

https://youtu.be/c33XAp06ba0

championc · 23-10-2020 6:46pm

Do you have two separate CT Clamps reading your Grid , with both of them on the same cable from the meter to your main board ?

You SHOULD have two CT Clamps on that cable. However, your readings appear to say different.

championc · 23-10-2020 7:10pm

daughy wrote: »

I'm no expert at the moment with the Eddie, but if you have the ct clamp connected to the live battery, and connected to the Harvi ct3 for instance, is there not an option on the Eddie to configure the ct3 connected live battery to avoid drain? I have my grid ct on ct1, my solar on ct2, and if in the future a zappi or batteries connected to ct3.

You cannot control the battery attached to a hybrid inverter, because battery power cannot be measured on the DC cables. CT Clamps are for the AC cables only.

That's why a number of us here have specifically installed separate Storage Inverters (to essentially have a Powerwall

daughy · 23-10-2020 7:31pm

championc wrote: »

You cannot control the battery attached to a hybrid inverter, because battery power cannot be measured on the DC cables. CT Clamps are for the AC cables only.

That's why a number of us here have specifically installed separate Storage Inverters (to essentially have a Powerwall

Does the ac backup on the hybrid solis not feed ac power to the main board? My understanding of this setup is, the Eddie ct clamp is connected to the main grid, the second ct is connected to the solar live main ac, then the third ct clamp is connected to the battery ac main live to the board, the dc conversion happens from the inverter and outputs to the ac backup which connects to the main board in your house.
Did that video on YouTube help at all gomamochi1? Did your supply grid settings on your eddie already have avoid battery drain enabled already?

daughy · 23-10-2020 7:37pm

I understand the confusion champion, I should have said the ct clamp connected to the live ac battery in my original post

championc · 23-10-2020 7:50pm

daughy wrote: »

Does the ac backup on the hybrid solis not feed ac power to the main board? My understanding of this setup is, the Eddie ct clamp is connected to the main grid, the second ct is connected to the solar live main ac, then the third ct clamp is connected to the battery ac main live to the board, the dc conversion happens from the inverter and outputs to the ac backup which connects to the main board in your house.
Did that video on YouTube help at all gomamochi1? Did your supply grid settings on your eddie already have avoid battery drain enabled already?

The AC cable from the Solar PV is the same AC cable which carries AC power derived from the batteries.

An Eddi actually only needs one CT clamp - the one on the Grid cable. The Eddi reads the excess and then ensures that it itself uses that same amount of power, meaning that excess is reduced to zero

A CT clamp on solar is purely for informational purposes when it comes to the Eddi. It's used for the Zappi

daughy · 23-10-2020 8:02pm

championc wrote: »

The AC cable from the Solar PV is the same AC cable which carries AC power derived from the batteries.

An Eddi actually only needs one CT clamp - the one on the Grid cable. The Eddi reads the excess and then ensures that it itself uses that same amount of power, meaning that excess is reduced to zero

A CT clamp on solar is purely for informational purposes when it comes to the Eddi. It's used for the Zappi

That's good to know champion, I was under the assumption the ac backup supplied the power to the main board from the batteries.
Sorry for going off topic.
So you basically need two ct clamps on the grid live if you have an eddie, and separate batteries?

championc · 23-10-2020 8:28pm

daughy wrote: »

That's good to know champion, I was under the assumption the ac backup supplied the power to the main board from the batteries.
Sorry for going off topic.
So you basically need two ct clamps on the grid live if you have an eddie, and separate batteries?

Eh ?

AC backup DOES supply power to your main board. However, this is over the same AC cable as your Solar PV which is sent out of the Hybrid Inverter (as opposed to PV power going into the batteries.

And you have two ct clamps on the main grid feed - one for use by your Inverter, and the second used by MyEnergi

daughy · 23-10-2020 8:52pm

championc wrote: »

Eh ?

AC backup DOES supply power to your main board. However, this is over the same AC cable as your Solar PV which is sent out of the Hybrid Inverter (as opposed to PV power going into the batteries.

And you have two ct clamps on the main grid feed - one for use by your Inverter, and the second used by MyEnergi

Im confused a little, my hybrid solis has, + and - ac grid, it also has + and - ac backup, it also has the dc + and - for the batteries, the hybrid has 2 inputs for the solar, 2 strings,
My dc from the solar is converted to ac and leaves the ac grid from the inverter, travels to the main board in the house.
The ac backup has nothing attached to it, are you saying that if one day I bought batteries, I have no need to use the ac backup ? The existing ac grid cable uses the battery to power the house?
Sorry for asking but I was confused about the ac backup on the solis hybrid, and the manual is a piece of sh-t

graememk · 23-10-2020 9:22pm

daughy wrote: »

Im confused a little, my hybrid solis has, + and - ac grid, it also has + and - ac backup, it also has the dc + and - for the batteries, the hybrid has 2 inputs for the solar, 2 strings,
My dc from the solar is converted to ac and leaves the ac grid from the inverter, travels to the main board in the house.
The ac backup has nothing attached to it, are you saying that if one day I bought batteries, I have no need to use the ac backup ? The existing ac grid cable uses the battery to power the house?
Sorry for asking but I was confused about the ac backup on the solis hybrid, and the manual is a piece of sh-t

Yeah the ac backup is to supply emergency power, if the grid goes down.

Normally just wired into a socket for simplicity, but can be wired into a sub board with a switchover for a couple of circuits. Like what would be done with a generator.

championc · 23-10-2020 9:23pm

AC grid powers the house, with that power coming from Solar, Battery or Both simultaneously. The system will deliver, as best it can, your house load at that moment in time.

AC Backup is EXACTLY what it says on the tin. If grid mains fails, it can deliver power as backup. So some people could ask an installer to install some emergency sockets off that connection

_dof_ · 23-10-2020 11:26pm

daughy wrote: »

This should help i hope with the avoid battery drain

https://youtu.be/c33XAp06ba0

That will only help is you have an AC coupled battery, like a Tesla Powerwall. Typically, the battery with a solar PV system is DC coupled, so the above doesn't work, since there's no AC cable to the battery to put a CT clamp around.

If you've a DC coupled battery, it's trickier to avoid draining the battery, since the Eddi/Zappi can't tell if current flow is coming from solar or the battery.

For Eco or Eco+ modes, you can set an export margin in the advanced menu, and they recommend setting that to 50W or 100W. That means the system will try to keep 50/100W exporting. The idea is that there'll only be a surplus (and therefore an export to the grid) if the current is coming from solar PV and not from the battery.

_dof_ · 23-10-2020 11:30pm

championc wrote: »

Do you have two separate CT Clamps reading your Grid , with both of them on the same cable from the meter to your main board ?

You SHOULD have two CT Clamps on that cable. However, your readings appear to say different.

???

You only need one CT clamp on the live of the grid cable, unless you've 3 phase, then you'd need 3, but 3 phase is very rare in Ireland for domestic installations.

EDIT: Ah, I see you're referring to the myenergi CT clamp and a different one for the inverter itself. Strange that the inverter would use a CT clamp and not a directly wired meter.

daughy · 24-10-2020 5:54am

_dof_ wrote: »

That will only help is you have an AC coupled battery, like a Tesla Powerwall. Typically, the battery with a solar PV system is DC coupled, so the above doesn't work, since there's no AC cable to the battery to put a CT clamp around.

If you've a DC coupled battery, it's trickier to avoid draining the battery, since the Eddi/Zappi can't tell if current flow is coming from solar or the battery.

For Eco or Eco+ modes, you can set an export margin in the advanced menu, and they recommend setting that to 50W or 100W. That means the system will try to keep 50/100W exporting. The idea is that there'll only be a surplus (and therefore an export to the grid) if the current is coming from solar PV and not from the battery.

I understand what your saying, in my case I have a CT clamp around the ac live solar flow to my main board, then it's connected to the harvi,
I also have the Eddie CT clamp around ac live grid, if in the future I get batteries I would have another CT clamp around the ac live grid connected to the harvi, and set as battery only.... would that eliminate battery drain as the harvi and hub can differentiate at that time whether it's actually solar power as il have the CT clamp on the ac solar live set in the Eddie as solar production only?
Just an idea, I haven't set up my Eddie as of yet as I need to install a new hot water tank, the one I have is corroding at the joints. Second hand home arrrghh.

championc · 24-10-2020 7:02am

_dof_ wrote: »

???

You only need one CT clamp on the live of the grid cable, unless you've 3 phase, then you'd need 3, but 3 phase is very rare in Ireland for domestic installations.

EDIT: Ah, I see you're referring to the myenergi CT clamp and a different one for the inverter itself. Strange that the inverter would use a CT clamp and not a directly wired meter.

I was explaining the setup that @gomamochi1 should be seeing. His Screenshot 1 is not just showing PV generation, but consumption and grid import & export. This is achieved by having a CT clamp on the grid cable. If the MyEnergi setup is to do the same thing, it ALSO needs it's own CT clamp on the SAME cable.

daughy · 24-10-2020 7:10am

championc wrote: »

Eh ?

AC backup DOES supply power to your main board. However, this is over the same AC cable as your Solar PV which is sent out of the Hybrid Inverter (as opposed to PV power going into the batteries.

And you have two ct clamps on the main grid feed - one for use by your Inverter, and the second used by MyEnergi

Unfortunately I don't have the inverter CT clamp connected to my main grid, the inverter came with an import export meter with a CT clamp but I didn't install it, that's why I just connected a CT clamp to my live solar, and a CT clamp to my live grid, both connected to the myenergi harvi.

championc · 24-10-2020 7:20am

daughy wrote: »

I understand what your saying, in my case I have a CT clamp around the ac live solar flow to my main board, then it's connected to the harvi,
I also have the Eddie CT clamp around ac live grid, if in the future I get batteries I would have another CT clamp around the ac live grid connected to the harvi, and set as battery only.... would that eliminate battery drain as the harvi and hub can differentiate at that time whether it's actually solar power as il have the CT clamp on the ac solar live set in the Eddie as solar production only?
Just an idea, I haven't set up my Eddie as of yet as I need to install a new hot water tank, the one I have is corroding at the joints. Second hand home arrrghh.

I think you're still a bit off in your understanding of MyEnergi products setup. The only use for a Harvi is to bring CT clamp readings wirelessly (via radio) from a location to a Zappi or Eddi, where it was impossible or impractical to run a wired connection.

In my case, my inverters are in my shed at the end of the garden. My Eddi is in the attic and my Zappi is right at the front of the house.

Finally, you have a hybrid inverter. You cannot monitor anything to do with battery power on Hybrid's. CT clamps are for AC cables only.

So with a Hybrid inverter, the MyEnergi app will only have a PV icon but will obviously show power coming from "PV" after sunset, which is obviously coming from the batteries. And if you were to charge the batteries from the grid, it would give the appearance of power being sent to the PV.

As I said previously, several people on this forum have SEPARATE second inverters connected to batteries only. A Tesla Powerwall is the same thing too - a dedicated inverter connected to a battery bank.

daughy · 24-10-2020 8:05am

I get you now championc. Was a bit confused about it but I understand. Tnx for the help

slave1 · 24-10-2020 8:15am

Just got my panels in the other day and starting to figure out my hub/harvi/zappi2 and CT clamps setup, above posts explain nicely, shame I never ran CAT cables to my consumer unit when I networked the house a few years back, never dawned on me

championc · 24-10-2020 11:08am

slave1 wrote: »

Just got my panels in the other day and starting to figure out my hub/harvi/zappi2 and CT clamps setup, above posts explain nicely, shame I never ran CAT cables to my consumer unit when I networked the house a few years back, never dawned on me

Although the cost of a Harvi can be annoying, it's an excellent gizmo and very clever the way they used 868,mhz radio to communicate between devices.

I would recommend that people trim off excess cable off MyEnergi ct clamps cables. I had some strange issues, which cleared when I cut off the bundle of wrapped up cable

slave1 · 24-10-2020 1:24pm

Yeah, I've gone for Harvi, when I get more time I may route CAT out of the attic and into my consumer unit to have the Hub closer to both the Harvi and Zappi2 but for the minute I'm just gonna see how I get on as is .. .

championc · 24-10-2020 4:13pm

Just another tip with MyEnergi - the Harvi can only be paired to the Master device. In my case, it struggled to to permanently send it's data to my Zappi, so I had to promote my Eddi to Master to get a solid permanent connection

_dof_ · 24-10-2020 5:25pm

championc wrote: »

Just another tip with MyEnergi - the Harvi can only be paired to the Master device. In my case, it struggled to to permanently send it's data to my Zappi, so I had to promote my Eddi to Master to get a solid permanent connection

I've only the Zappi and Hub, no Eddi, but sometimes the hub loses the signal to the Zappi, changing from default channel 1 to channel 4 helped a lot, but stlil some dropped signals. I think it's because the Zappi is on a wall which was drylines so there's foil backed insulation behind it, so that's probably blocking some of the signal.

Solar PV Hints, Tips & Troubleshooting

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