Load voltage too high

Question

question

maha asked May 3, '20

Load voltage too high

I use a ESS-System with a Fronius on AC-in and a MPPT 250/100 on AC-out and DVCC is enabled.

Absorption voltage in the MultiGrids is set to 57.6V and in the MPPT too.

In this constellation the load voltage will rise until 58V. Therefore I set absorption voltage to 57.2V in the MultiGrids and then the max. voltage is 57.7V. It seems that the MPPT will oversteer the voltage of the MultiGrids with 0.4V. I thought that the MultiGrid will be the master...

In DVCCMenue SVS is disabled.

When SVS is enabled it's the same - voltage too high!

Is that a bug?

ESS mppt charging

1588493233106.png (38.8 KiB)

1588493542674.png (22.7 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.

Modifications Space

Node Red Space

Answer 1 · 2020-05-03T08:40:05Z

maha answered · May 03, 2020 at 08:40 AM

Batteries are 4x 170Ah Hoppecke OPzV (Gel).

I don't measure with a Multimeter. I think that the MPPT oversteers the MultiGrids and that shouldn't be in a ESS-System...

1588495147963.png (20.3 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 · 2020-05-03T09:39:49Z

Daniël Boekel (Victron Energy Staff) answered · May 03, 2020 at 09:39 AM

Hi @MaHa

When 'feed-in excess solarcharger power' is selected, the MPPT charge voltage is set 0,4V higher so the multi can 'pull down' to the actual charge voltage and send the rest to the grid.

so yes, multi is still master here.

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.

maha commented · May 03, 2020 at 11:39 AM

Thank you for your information.

I had already thought so and therefore also reduced the value in the MultiGrids.

Here you can see what happens when sunshine comes and goes and the MultiGrids are using 57.6V absorption.

0 ·

1588505948171.png (20.3 KiB)

1588512633390.png (19.1 KiB)

question