ESS Fronius overcharged batteries during grid cut off, no more limitation !

Question

question

josephm asked Jun 1, '21

ESS Fronius overcharged batteries during grid cut off, no more limitation !

Hi !

I'm new on the forum ! I have since january a Multiplus2 (v482) 5kW, Fromius 5kW at the AC exit of the Muliplus (TCP modbus) and 3,7 kw Panels with Leaf Batteries last generation. Yesterday, the system did not stop charging the battery, the limit I fixed is 56,8V (14 cells), but it has reached 66V ! My BMS was connected but I did not connected to the battery switch (I regret a lot!!). I use the multiplus as a bateery controler. I hope I did not kill the batteries, I was on vacations and saw too late, I called a friend to stop everything, I was so afraid that the house burns :(

battery charging Lithium Battery

1

2 |3000

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

josephm commented · Jun 01, 2021 at 09:48 PM

Also at same time, I realized that injection was off and it happened when I lost the grid. Maybe it can explain the issue ? When I had the grid on, the multiplus was limiting the Fronius even if no injection, but with the grid was off, I don't know why the fronius was not limited anymore, even if the SoC was 100%.

0 ·

2021-06-01-21-28-31.jpg (258.7 KiB)

Modifications Space

Node Red Space

Answer 1 · 2021-06-07T12:36:56Z

josephm answered · Jun 07, 2021 at 12:36 PM

I'm back from vacations and I made new test, same problem ! The victron communicate to Fronius Primo to lower the power when the batteries are full, but if I loose the grid, the fronius continues injecting to the batteries, the multiplus does not regulate anymore ! Very very dangerous !! Please HELP !

overcharge.jpg (211.6 KiB)

no-more-limitation.jpg (78.4 KiB)

overcharge.jpg (212.3 KiB)

2 |3000

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

Answer 2 · 2021-06-07T23:12:31Z

palom170 answered · Jun 07, 2021 at 11:12 PM

Have you configured the ess selecting that the system has a inverter on AC out?

And, have you set up the fronius in mg50 or 60hz? Have you change this value in fronius? Or does it keep configured in your country?

2 |3000

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

Answer 3 · 2021-06-08T11:55:02Z

tozz answered · Jun 08, 2021 at 11:55 AM

What you should be doing first is properly connect your BMS battery disconnect contactor. You knowingly did not connect a critical safety component in your setup. Yet, you are blaming the software. The only one to blame here is you.

Fix your house-burn-down-risk first and then troubleshoot the rest of your installation. There can be plenty of reasons why batteries are overcharged (eg. faulty hardware).

Fix your hardware first!

2 |3000

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

Answer 4 · 2024-03-11T02:23:13Z

vavaroutsos answered · Mar 11 at 02:23 AM

Regardless of not properly connecting the battery cutoff, there is a bug in the ESS/DVCC/Venus GX control. I have a small system in my RV with Venus GX (v3.22), MPPT (v1.61), Multiplus (v424), BMV-702 (v3.11). I configured it with ESS system (I know, Victron says not to in RV/boat), however, I wanted some of the advanced charge control features. If I'm not on grid power, and the Multiplus is switched off, the Venus GX turns the MPPT on full power without regard to the charge voltage limit. The MPPT is still under external control. I know under this configuration/condition, the MPPT should be using the Multiplus charge parameters. So I suspect there is a bug when the Multiplus is turned off with sending appropriate charge parameters to the MPPT. Regardless of where charge parameters are/aren't coming from, I feel the Venus GX should make sure the charge voltage and current limits are not exceeded.

2 |3000

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

question