question

tranzorb avatar image
tranzorb asked

ESS with DVCC and DC-coupled PV surplus injection buggy?

Hello All,

I am facing an issue with my system, which is made of the following :

Multiplus 48/10000/140/100, Fronius Primo 8.2-1 on the AC out with 12kwp solar panels, 75kw Li-ion battery pack on CAN BMS, and an MPPT150-35 with 1.2kw solar panels on the DC side. An external EM24 ethernet meter is used. All are to the latest firmware.


my-setup.jpg

The system is configured as ESS, with limited injection, and DVCC is ON.

And now the issue :

When I activate the DC coupled surplus injection in the ESS settings, the Charge Voltage Limit (CVL) is not anymore followed by the system. Instead, the batteries are charged to CVL+0.4V. This seems to be "normal", as per Victron DVCC operating manual. However, when there is no more sun, the batteries are discharged to the grid at the limited power defined in ESS/Grid Injection settings, until the battery voltage reaches CVL.

With DC coupled surplus injection de-activated, the battery charges to CVL (not more), and there is no grid injection from batteries when there is no more sun.


Request (please) :

Since I did not find it, is there an option to avoid draining battery in the grid with DVCC and DC coupled surplus injection activated, and remove the +0.4v offset? Otherwise, it would be of great use to add it.

Thank you,

Fred


ESSgridDVCCess discharging
my-setup.jpg (223.7 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

7 Answers
derrick thomas avatar image
derrick thomas answered ·

Is your desire to feed in excess mppt to run loads and not discharge batteries unless there is a loss of mains? You could use 'keep batteries charged' and the batteries will only be discharged when the output loads exceed the ac input limit or there is a loss of mains.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

tranzorb avatar image
tranzorb answered ·

Thx,

Actually not. I just want to be able to feed-in with DC coupled MPPT, BUT i do not want the battery to be drained into grid when there is no more sun and its voltage is between CVL and CVL+0.4. I also want the battery to supply all loads when there is no sun or not enough sun, even if grid is present.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

tranzorb avatar image
tranzorb answered ·

Any idea?

Thx,

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

smartdiy avatar image
smartdiy answered ·

I had the same problem, so I thought that if feed-in does not allow me to control the charging process via bms, at least I will use the maximum energy from dc mppt to charge the battery. So I decided to disable the charger in the multiplus, but that doesn't work properly either. You can see what miracles are happening in the post I added here:


https://community.victronenergy.com/questions/203226/why-does-turning-off-the-charger-in-the-multiplus.html?childToView=203787#answer-203787


I think the only way to use the power of the panels connected to the dc mppt is to hide the ac inverter, only then all this ess doesn't make any sense.


2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

ondra avatar image
ondra answered ·

I have same problem.

https://community.victronenergy.com/questions/80620/ess-mode-ignores-bms-bmz-ess-x-control.html?childToView=197334#comment-197334

I have been trying to solve this for a long time, unfortunately without success... no one is responding. I had to cancel the mmpt regulators and replace them with an inverter :-(

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Rob Duthie avatar image
Rob Duthie answered ·

Hi All

Small bug with the DVCC preset settings?

Had a problem with a Dyness battery system to make it export DC surplus was to turn off the DVCC SVS voltage share. Not preset in the DVCC for that brand of battery.

With the Pylontec batteries not a issue as the standard setting is forced OFF and DC exports OK.


Regards

Rob D

NZ

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

lucca371 avatar image
lucca371 answered ·

My CVL is 55,2V. DC coupled feed-in (over MPPT's) works in my case only when i set DVCC --> managed battery voltage --> maximum charging voltage to 54,4V. The battery will still be full.

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

thekwchallenge avatar image thekwchallenge commented ·

What BMS are you using Lucca? My CVL is also set to 55.2 in my BMS and in my DVCC. Feed in is enabled but does not work since I changed to a Seplos BMS. It worked fine with the same setting using a Batirum BMS

0 Likes 0 ·
lucca371 avatar image lucca371 thekwchallenge commented ·

You have set DVCC --> managed battery voltage --> maximum charging voltage to 54,4V.???
I use Gobel Power GP-SR1-RN150 with Refinergy BMS.
It is important to set the voltage to 54.4V.

0 Likes 0 ·

Related Resources

What is ESS training video

ESS Quick Installation Guide

ESS design and installation manual

Additional resources still need to be added for this topic

DVCC chapter in GX manual