question

goose avatar image
goose asked

Pylontech High voltage: 53.96V when DVCC set to limit at 52V...

Good day!

I have an existing Pylontech installation that suddenly started pushing voltages too high.

The only change was ESS set from "Keep batts charged" to "Optimized with battlife"

By returning it to "Keep batts charged" does not help

The errors then started. It seems to be the MPPT not following the set voltages.

1626626466084.png


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All settings were confirmed with this guide: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

System details:

  • Venus GX
  • Quattro 48/8000/110-2x100 rev2
  • SmartSolar Charger MPPT 250/100 rev2
  • 2x Pylontech US3000B
  • 3x Pylontech US3000C
  • All firmwares updated to latest when errors started - did not help.

Venus GX settings

1626626649703.png

(Charge voltage was set here to 52V only as a test, it did not help)


Quattro settings:

1626626717707.png


MPPT Settings:

1626627004077.png


Any assistance ill greatly be appreciated!

Regards

MultiPlus Quattro Inverter ChargerESSPylontechDVCC
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marv21 avatar image marv21 commented ·
Can you show the BMS Parameters please?
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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Lukas and @Goose,

This situation can occur when there is some voltage overshoot, such as when there is a large PV array, large loads, and a full battery. When the load turns off, the PV can take some small time to adjust, and a bit of energy goes into the battery. It's a small amount, but it adds up. Pylontech seems particularly sensitive to it in my observations.

My suggested remedy is in the ESS "Grid feed-in" menu, enable AC and DC-coupled PV - feed in excess, and then enable Limit system feed-in and set the maximum feed-in to 0W. This should resolve this slight excess build up situation (and the battery voltage increasing, and ultimately warnings and shutdowns).

cleanshot-2021-07-24-at-223848.jpg


Note - please I would suggest to keep Shared Voltage Sense disabled. I think in this particular situation, the slight additional delay that it can cause will also lead to more harm than good. But of course there are some installations where the reverse can be true, when voltage drop/rise is significant.



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lukas avatar image lukas commented ·
@Guy Stewart (Victron Community Manager)

Nice, thanks for the ultra fast feedback! Hope this helps @Goose for his overvoltage issue.

For the overcurrent, this all started when I enabled feed-in which is required by the my-PV dump load heater we installed in addtion to the victron installtion. Without feed-in, the BMS current setpoints are well respected...at least in my installation...the pylontechs drop down significantly in terms of allowed charge current, once fully charged at around 52-52.2V as they start balancing the pack in each unit. Can I supply any further useful information in addition to the other threads?

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goose avatar image goose commented ·
Hi @Guy & @Lukas

Thank you for the help so far!

I have made the changes and will go out to the site and reset the MPPT.

I will revert back as soon as I have some results.

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goose avatar image goose commented ·

Hi @Guy

It seems like your suggestions is working correctly with "Optimized with battlife"

I have switched over to "Keep batteries charged" mode, and will revert back with results. Looks promising so far!

Thanks!

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Javier San Juan Costillas avatar image Javier San Juan Costillas commented ·

Hi @Guy Stewart (Victron Community Manager) out of desperation I kept lurking around the forum and found this post. I have similar issue but inverse, I have feed-in active without limit, and tested with limit now but still get this weird high voltage alarms. I had the system working fine for almost a year, as soon as I activated the feed I started to get regularly this high voltage alarms.

Pylontech is saying Victron its pushing higher voltage thus the spike.

My post is here. https://community.victronenergy.com/questions/99322/quattro-15000va-and-pylontech-us3000-high-voltage.html

Please let me know if there is known issues and what will be the workaround.

Thanks!

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Rob Duthie avatar image
Rob Duthie answered ·

Use without battery life

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goose avatar image goose commented ·
Hi Rob!

Thank you for you answer, unfortunately I cannot see how this will solve my problem?
Also regarding warranties of batteries this is not a good method - or am I missing something?

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lukas avatar image
lukas answered ·

Can you try with "Shared Voltage Sense" enabled pelase? I had a similar issue where the voltage setting was ignored. In the old pylontech manual from victron, SVS should be set to on -> now it is stated that it should be off and I really dont know why. But enabling SVS helped in my case, I did not notice any strange behaviour so far...

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goose avatar image goose commented ·

Thank you!

Will give this a try and revert back here... Unfortunately I have to go to the site to clear error #38 on the MPPT..


EDIT: I did reset the MPPT - will wait for the sun tomorrow and check

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goose avatar image goose goose commented ·

SVS did not help.

Today I got the same:

1626775772022.png

1626775866473.png


Why is the Victron system charging to higher voltages even with the limit set to 52V?
Seems to only happen now with "Keep batteries Charged"


Also worth noting, in "Keep batteries Charged" mode it seems like as soon as the battery is full, the surplus PV is not powering the loads as before....

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lukas avatar image lukas goose commented ·
hm ok - for me, problems started when I enabled the DC grid feed-in option...I need this however, such that a dump heater can detect the surplus and "charge" a hot water storage tank...

Not sure if you also enabled this...what's the overall operating mode of the installation? ESS, or something else? Also, does the voltage stay that high or is it just a momentary peak once the batteries are fully charged?

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goose avatar image goose lukas commented ·

Hi lukas

The system is ESS - but grid feed in is disabled.

As far as I can see it is not a momentary problem:

1626959900200.png



So far it seems like the problem is only when set to "Keep batteries charged"

So running in ESS in Optimized and min SOC at 100% is also not ideal as battery is discharged to some degree I see.... Also surplus PV power is not optimally used to power loads in the mode when battery reaches 100%


Nothing changed in the system when the errors started - only the Venus auto-updated

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lukas avatar image lukas goose commented ·

Hi,

@Goose had a working installation, then it seems like somethings changed within DVCC and now he's getting overvoltage situations. Also, I'm getting overcurrent conditions sometimes in my installation when the BMS requests a limited charge current due to balancing - the current limit set by the BMS is ignored. We already discussed this in other threads, and I also posted graphs from VRM and grafana. @Goose also included some graphs. But somehow, the conversation got stuck in other threads and I don't know if the issue already investigated behind the scenes - so some information would be great.

In my opinion, some change within the last versions of DVCC broke adhering to the limits set by the BMS, at least for pylontech batteries. I don't want to sound like a drama queen here, but this is a serious issue...neither overvoltage nor overcurrent is a good thing battery safety wise...

Cheers,

Lukas


P.S: Again for reference:

https://community.victronenergy.com/questions/91148/dvcc-limit-charge-current-not-working-with-grid-fe.html?childToView=94396#comment-94396

https://community.victronenergy.com/questions/95058/high-charge-current-warning-with-grid-feed-in.html?childToView=95072#answer-95072


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