lebea-mabogale avatar image
lebea-mabogale asked

EASYSOLAR-II-48-3000-35-32-GX voltage drop

We have seen a lot of Low Voltage warnings and Alarms on this Plant, and I think I understand what is going on here.

Initially, we suspected excessive resistance of the battery cables and fuses, but our calculations show this to be around 10mΩ.

That would only result in 1V drop from the battery to the VE.Bus at 100A, which is way less than drop that the logs for 21 Sept show (see attached graph).

Looking closely at the sequence of events around 05H35, it is clear that the VE.Bus voltage drops sharply just after the SoC setpoint of 40% is reached, and then immediately recovers. It's not a battery current problem, as that was even higher at 05H01.

So what I think is happening is that the transition from Battery power to Grid power has a dead band that is too long for the inverter's internal reservoir capacitors to sustain the VE.Bus rail voltage.

To fix it, there are two options:

  • increase the capacitors (not viable in this case)
  • reduce the dead-band with a firmware update

Please advise,


EasySolar All-in-OnevoltageVE.Busbattery system voltagevoltage drop
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1 Answer
Alexandra avatar image
Alexandra answered ·

@Lebea Mabogale

Do you allow peak shaving at min SOC?

When the system is checking the connection and preparing to connect it hums a bit (this is the transformer being saturated). The grid aconnects then the inverter power assists from that"reservoir". What seems to be missing is the discharge from battery to assist on grid connect.

If it is not doing that, then something is not quite right. What are the grid settings on the inverter? Are you using a grid code? What LOM is set?

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lebea-mabogale avatar image lebea-mabogale commented ·

Hi @Alexandra

1. Peak shaving is set on (1) Above min SoC
2. South African grid code is selected; Above grid code selected plus LOM B (compliant)

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Alexandra avatar image Alexandra ♦ lebea-mabogale commented ·
Does it hum extra before connect? And do you see power assist in the ve bus stat on VRM?
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Related Resources

What is VE.Bus?

EasySolar 1600 product page

EasySolar-II GX 3000 & 5000 product page

Additional resources still need to be added for this topic