When the batteries are full, the electricity production drops.

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question

badsensor asked Mar 5, '23

When the batteries are full, the electricity production drops.

Problem: When the batteries are full, the electricity production drops.

Location: Costa Blanca, Spain.

Large house in a rural area connected to the electricity grid.
Purpose: use the solar/battery setup with the electrical grid as backup, usually on short or cloudy days.
Battery minimum set to 20% for lifespan.

EDIT: I forgot to mention that I have a contract with the electricity company (Iberdola) to send my excess power to the grid.

I searched the forum for similar problems, but non I could find for my setup.

System setup:

20 x Solar Panels Longi LR5-72HPH-535M

2 x Victron Energy SmartSolar charge controller, MPPT 250 | 100 - Tr VE.Can

(10 panels into 1 MPPT, twice)

1 x Victron Energy MultiPlus-II 48V | 10000 VA | 140 AMP, AC transfer capacity 100 A, Inverter 230 V

1 x Victron Energy Venus GX

8 x Battery PylonTech US3000C

The system works as advertised until the batteries are full., usually around 13:00 - 14:00 hr, on a sunny day.

- Then, when the sun is very bright, I receive emails from the VRM notifier:
High voltage alarm: Alarm

High discharge current alarm: Alarm

After 1 to 2 minutes:
High voltage alarm changed from 'Alarm' to 'No alarm'

High discharge current alarm changed from 'Alarm' to 'No alarm'

This cycles for a couple of minutes, and then I receive this email:

The installation “my-name” has generated a high volume of alarms. Suspending alarm notifications for 24 hours.

Or, when the sun is less bright, I don’t receive warning email.

- Then, from the moment the batteries are fully charged, I see yield dropping on the charge controllers, sometimes up to zero, like this at 14:08 hr on a sunny day:

Also, the APC BX1400U-GR UPS I have installed in my office makes a lot of clicking noises during this ‘low yield’ period.

A typical sunny day, no clouds, looks like this:
Sunrise 07:30, sunset 19:00
EDIT: new screenshot with to to/from grid numbers:

The moment the batteries are full, the chargers, or something else, starts to play up, and the yield drops significantly.

I think it should look like this:

Screenshot from 15:55 hr that same afternoon (sunny day, no clouds):
(PV charger can be as high as 10400 W)

Can anybody help me find out what is going on?

My Spanish dealer keeps telling me everything is fine, but now he starts to recognize there is a problem.

My electrical knowledge is limited, but I have a feeling something is not adjusted right?

Please let me know what further information you need.

Many thanks in advance for all the help guys!

Multiplus-II MPPT Controllers

schermafbeelding-2023-02-28-om-140841-kopie.png (18.9 KiB)

projection.png (82.4 KiB)

onthat-same-afternoon.jpg (33.6 KiB)

with-feed-to-grid.png (138.7 KiB)

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Answer 1 · 2023-03-05T15:32:09Z

matt1309 answered · Mar 05, 2023 at 03:32 PM

Hi @badsensor

The high voltage alarm may be due to the voltage not being configured quite high enough, or the absorption/float voltages in the charge controller being too high. ie the alarm is going off every time the batteries are full. I personally set the alarm voltage slightly higher than absorption voltage to avoid the alarm everytime but still get notified when/if there's a fault in the system causing voltage to peak.

In regards to your other question around MPPT ramping down it's output when batteries are full. Just so I'm understanding correctly, you're wondering why this happens?

Say for example you've not got any loads and are not connected to the grid theres no where for any excess power to go.

ie If you're panals are outputting 1000w but your loads are only 200w and your battery is full you've got 800w of excess that can't go anywhere. The MPPT should then ramp down to just cover the 200w of loads. If it didnt your battery would be charged too much.

If you want to keep MPPT outputing 100% of what it can you either need to use more power or connect to a grid/source where you can export power (ensure this is legal and allowed within your area).

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badsensor commented · Mar 06, 2023 at 09:52 AM

Hello matt1309,

Many thanks for your answers.
I will pass your 'high voltage alarm' info on to my dealer.

Regarding the 'power to grid', I edited my post with the fact that I do have a contract and that the surplus power is sent to the grid.

My question should therefore be: why is it throttling the chargers while having surplus energy available to send to the grid? (it does it only when the batteries are full).

Here is a screenshot from this morning, sunny sky, while charging the batteries and a little power feeding into the external grid:

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normal-morning-situation.png (216.2 KiB)

matt1309 badsensor commented · Mar 06, 2023 at 10:17 AM

Hi @badsensor

If you go into your cerbo gx/venus os settings then go to. ESS make sure you have Feed in excess power enabled. It sounds like it's disabled at the moment.

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badsensor matt1309 commented · Mar 06, 2023 at 02:11 PM

Hi matt1309,

Many thanks for your input!
I am trying to locate 'cerbo gx/venus os settings', can you guide me where to find this?
Under which tab is located?

Dashboard
Advanced
Device list
Settings
Remote Console
Notes
Photos
Share
Alarm logs
Event logs
Reporting

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matt1309 badsensor commented · Mar 06, 2023 at 02:39 PM

If your installer has setup remote console access it will be under "remote console".

Then once that opens you will see venus os/cerbo gx menu. You then need to press space bar to and select Menu->Settings-> Then scroll down to ESS -> then scroll down to grid feed in. Those will be the settings you are looking for.

If however remote access isn't setup you need to be on the same network (same wifi connection) as the cerbo gx/venus os. And find it's IP address and paste that into your browser.

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badsensor matt1309 commented · Mar 13, 2023 at 12:03 PM

Thanks for your help!

I followed the menu and found the settings,I think all are set as you suggested.

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schermafbeelding-2023-03-13-om-125733.png (73.2 KiB)

Answer 2 · 2023-03-05T15:36:32Z

matt1309 answered · Mar 05, 2023 at 03:36 PM

If you're connected to the grid you can enable feed-in excess in ESS. However the operation you're describing is correctly configured in my opinion.

If I take your example if panels were producing the 10400 you'd have over 9000w too much power that couldn't go anywhere.

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badsensor commented · Mar 06, 2023 at 10:10 AM

I don't feel qualified enough to change settings in the ESS.

Will pass this on to my dealer, thanks!

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matt1309 badsensor commented · Mar 06, 2023 at 10:18 AM

Totally understandable. They will also be able to ensure you're within any limits that are required for your local area. ie ensure you dont export more than your local network/grid provider allows.

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Answer 3 · 2023-03-05T21:02:42Z

kenzo answered · Mar 05, 2023 at 09:02 PM

To me it doesn’t look like you are in fact connected to the grid, your AC-IN seems disconnected from the screenshot you shared. In that situation, the behavior described would be perfectly normal.

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badsensor commented · Mar 06, 2023 at 10:17 AM

Hi kenzo,

Thanks for your reply.
You are correct, in that situation it shows the grid disconnected.
But normally it is connected, see the screenshot above.
It is part of the 'misbehavior', again: only when batteries are full, it cycles between connected and disconnected, and MPPT's throttling.

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nickdb ♦♦ badsensor commented · Mar 06, 2023 at 10:22 AM

If grid keeps disconnecting when it tries to feed back, sounds more like a grid/meter issue.

Smart meters can do that if programmed incorrectly by the utility.

It should be easy to reproduce.

When batteries are charging and solar is running, set a large negative grid-setpoint in ESS, if your AC disconnects, you have a utility issue.

In any case, since you don't know the system, your installer should come out and resolve this for you.

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Michelle Konzack badsensor commented · Mar 07, 2023 at 09:42 AM

Ehm, did you say, the MultiPlus-II DISCONNECT from the Grid if the Batteries are full?

Then the behaviour of the MPPT is correct and the ERROR sit in the MultiPlus-II or Cerbo GX.

This seems to be a misconfiguration

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Answer 4 · 2023-03-06T07:18:24Z

Michelle Konzack answered · Mar 06, 2023 at 07:18 AM

From the last screenshot I see, that the grid is disconnected and if this is realy a sunny day, then your Solarpanels should cover the whole load on the Inverter (762W) and should NOT suck 694W out of the batteries...

I have more or less the same installation and once the batteries are in FLOAT 27,6V my Solarpanels take over ANY load up to 1500W and my batteries are not used until the sun is not more enough.

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badsensor commented · Mar 06, 2023 at 10:23 AM

Hi Michelle,

Thanks for your reply.

"if this is really a sunny day, then your Solarpanels should cover the whole load on the Inverter"

Exactly! But this is not what is happening. It behaves very erratic.

Can you explain FLOAT to me?

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Michelle Konzack badsensor commented · Mar 07, 2023 at 09:46 AM

The MPPT has 3 stages of charging

1) Bulk (charging with max current)

2) Absorbtion (reduce current and increase the voltage to get the Batteries full)

3) Float ( keep the Batteries full at a certain voltage and only supply more power if a load try to pull the voltage UNDER the FLOAT Voltage)

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badsensor Michelle Konzack commented · Mar 13, 2023 at 11:41 AM

Hi Michelle,

Thanks for this explanation! I did not know that.
Currently, I have a fourth stage: External Control, see image.
Is that my electricity company preventing my system to feed power into the grid?

12:28 LT, conditions sunny sky:

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schermafbeelding-2023-03-13-om-122851.png (202.3 KiB)

Michelle Konzack badsensor commented · Mar 13, 2023 at 08:48 PM

I think, you should contact your electricity or grid provider. Could be, that "external control" was triggered by them.

In Germany and France it is standard, but it does not exist in Estonia for example.

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badsensor Michelle Konzack commented · Mar 15, 2023 at 08:55 AM

Yeah, I will do that.

Will have to go to a physical office in town since their call center is mostly absent.
I will update.

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paulcupine badsensor commented · Mar 15, 2023 at 11:03 AM

"External control" simply means that the battery management system is controlling the battery charging instead of the inverter. It has nothing to do with your grid operator "controlling your system".

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badsensor paulcupine commented · Mar 16, 2023 at 05:13 PM

Hi paulcupine,

Great, thanks for letting me know this!

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Answer 5 · 2023-03-06T08:09:12Z

andrebotha answered · Mar 06, 2023 at 08:09 AM

I have the same issue, ive seen this type of behavior being posted more often now.

https://community.victronenergy.com/questions/179977/ess-not-feeding-back-to-grid.html

Its like Victron did a software update and its messing with everything. My MPPTs also switch off after my batteries are fully charged and does not push back to grid.

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badsensor commented · Mar 06, 2023 at 10:35 AM

Hi andrebotha,

Thanks for your reply.

I looked at your link, and it is indeed very similar to my problem.

I hope people from Victron are reading these comments and come up with an answer!
My problem is that I feel not confident enough to change setting in the ESS panel.

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badsensor commented · Mar 13, 2023 at 12:08 PM

Do you also see 'External Control' in that situation?

I am starting to suspect that the electricity company is preventing my system to send electricity to the net.

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Answer 6 · 2023-03-07T01:10:31Z

astrayan answered · Mar 07, 2023 at 01:10 AM

I wonder if it's because the grid doesn't want the power. More and more solar means an overloaded local grid, that goes high voltage, and the supplier has to reject all the solar power. This is happening in Australia a lot.

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ejrossouw commented · Mar 07, 2023 at 08:15 AM

From what I understood there was a requirement introduced by grid operators to have a mechanism by which they can indeed stop inverters from feeding in when there is excess solar production.

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badsensor ejrossouw commented · Mar 13, 2023 at 11:48 AM

I start to think this is going on here.

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Michelle Konzack commented · Mar 07, 2023 at 09:37 AM

And in Germany the Grid provider can remotely shutdown (since ever) your Solarinstallation to prevent overloading of the grid (but you get anyway payed even without feed-in)

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badsensor commented · Mar 13, 2023 at 11:34 AM

Hello astrayan,

That sounds logical, however, I did not receive any notification from my power company that they do so. I will investigate more.

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Answer 7 · 2023-03-15T20:26:44Z

tom w answered · Mar 15, 2023 at 08:26 PM

@badsensor

The inverter's feed in is controlled by the grid frequency. The higher the grid frequency the more the feed in will be limited. When there is too much power in the grid generators will spin faster and frequency will go up and your inverter is supposed to decrease it's output power.

Next time you see that the power dropping for no reason, go and check the grid frequency in the remote console of your Multiplus. If it's higher than 50.2Hz there are too many systems trying to feed in their solar power.

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badsensor commented · Mar 16, 2023 at 08:09 AM

Hi Tom,

Thanks for your remarks, very useful!
I will check this afternoon and report back here.

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badsensor badsensor commented · Mar 16, 2023 at 04:54 PM

I got these readings from the remote console, freq from net input 50.1 Hz alternating to 49.9 Hz. I did not see 50.2 Hz at all.
But something [external] is controlling the inverter.
Sunny conditions.

Edit: I learned from user paulcupine that "External control" simply means that the battery management system is controlling the battery charging instead of the inverter.

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schermafbeelding-2023-03-16-om-153741.png (528.4 KiB)

tom w badsensor commented · Mar 17, 2023 at 09:21 AM

Ok your not limited by the grid frequency.

Your SOC is 100% so the ESS should feed in unless it's limited by some settings.

Did you check if "Grid feed-in" under ESS settings is active?

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2023-03-17-10-12-08-remote-console-on-lan-brave.png (44.6 KiB)

badsensor tom w commented · Mar 17, 2023 at 11:19 AM

Hi Tom,

These are my settings:

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schermafbeelding-2023-03-17-om-121422.png (64.0 KiB)

badsensor tom w commented · Mar 22, 2023 at 12:13 PM

I checked with my electricity company, and they confirmed they do not limit my output to the grid.

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Answer 8 · 2023-03-15T20:33:45Z

jdb answered · Mar 15, 2023 at 08:33 PM

https://powernsun.sa/longi-mono-perc-440w-mono-crystalline-solar-module-lr4-72hph-440m-3

Voc =46,26V

you said setup was:

20 x Solar Panels Longi LR5-72HPH-535M

2 x Victron Energy SmartSolar charge controller, MPPT 250 | 100 - Tr VE.Can

(10 panels into 1 MPPT, twice)

10*40V is already 450V and your MPPT is 250|100 which stands for 250V 100A,

450V >> 250V

Are you sure this setup is ok ?

Has the MPPT calculator been used ?

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Valentin Bonnet commented · Mar 15, 2023 at 10:06 PM

In his setup the panels are most probably installed in strings of 4 or 5 panels, thus under 250v.

Probably two strings of 5 panels per mppt.

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badsensor commented · Mar 16, 2023 at 05:20 PM

Thanks for your reply,

I have no idea!

I am sending this remark to my dealer, I will keep you posted.

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badsensor commented · Mar 22, 2023 at 12:16 PM

I checked with the installer, and the panels are 2 x 5 in parallel, twice.

So the 250V setup is okay.
Thanks for your remark!

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Answer 9 · 2023-03-17T03:14:58Z

astrayan answered · Mar 17, 2023 at 03:14 AM

No sure if this is the same problem. His power to grid mysteriously drops when the battery is full

https://community.victronenergy.com/questions/185963/mppt-power-is-limited-for-dc-feed-in-if-battery-is.html

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