Battery going offline when min SOC reached

Q&A and troubleshooting
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1

Hi,

Hoping someone has seen this before (or maybe its a feature in new versions)

I recently did updates on all components of my system:

  • Victron 5kw inverter

  • 3 x pylontech batteries

  • Gx device

After the update I noticed that now when my system reaches min soc it shows 1 battery is offline:

Screenshot_20260702_204802_VRM
Screenshot_20260702_204802_VRM3120Ă—1440 261 KB

If I change min soc to be a bit higher then all 3 batteries show online and it charges to min soc then 1 goes offline.

In the morning when sun is shining and its charging all is fine and 3 batteries are online until the end of the day when I reach min soc again.

I looked at the batteries and when it reaches min soc and a battery goes offline then there is a red light on my master battery.

No alarms on my system in VRM.

Anybody seen this behavior?

2

How are your batteries connected (power wise)?

3

Yes. Seen it
They do that when they are unhappy.

The reason is one unit is blocking charge or discharge. In your case discharge. Its probably reaching a loww threshold before the others
Try rotation in the bank and see if that helps.

4

Ah thanks!

So a bit more info - I have 2 x US3000C and 1 x US2000

Could the US2000 be the issue since it’s smaller and running out of capacity sooner?

The US3000C is my master battery and it is the 1 that has the red light on when min soc is reached (I set it to 30% recently… maybe I must increase it)

5

Do you think keeping the bank at 100% for a few days to balance it out might help?

6

IMG-20260630-WA0083
IMG-20260630-WA00831920Ă—3413 742 KB

Does this answer your question @DuivertNL ? Its been working fine like this for a few years.

7

Looks ok, what battery is the newest?

8

Is the 2000 a newer or older one?
I would have it in the middle of the stack.

Its possible a good charge is all it needs. How often does it get to full?

9

The 2000 is the oldest battery. What is the benefit of having it in the middle? (Asking to learn) :slight_smile:

I have set my system to keep batteries charged so will leave it for a few days at full charge to see if it helps.

It was getting to full charge daily but for the last 2 months my solar wasn’t working 100% (blown fuse) so it didn’t. That has been fixed 2 weeks back.

10

The way the stack will current share. The battery in the middle will work less than the outer ones.

11

Ok that makes sense - thanks for that. Will arrange to have that done.

Changed ESS setting to keep batteries charged so will leave it like this for 2 days then test again.

12

@lxonline I kept it at full charge from Friday to Monday and then changed it back to “Optimized with BatteryLife” . Unfortunately it is still doing the same thing.

Is the next step to change the order of the batteries and put the US2000 in the middle?

Is there anything else I can check?

13

Swap them over.

I have no idea what else to suggest unless you are able to work out which battery is going offline. The light on the master may not be helpful as it is the master