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Axpert + Pylontech + MultiSIB configuration problem

David at SolutionCentre

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We have recently commissioned a solar project - It consists of -

2x Axpert 5kW  inverters
2x Pylontech 3000C batteries
24 x 465W PV panels (2x 5085W banks)

We installed the MultiSIB software on RS232 and RS485 and configured change over from grid to battery - it works in one direction (to grid - SUB mode) but does not switch back to battery (SBU mode). 

Settings are as follows -

Charge - solar only
Source to utility change 47V
Source to battery change 48V
Battery low/cut off 45.9V
Battery type USER
Bulk charge 53.2V
Float charge 52.5V

Mode control in MultiSIB
SOC to grid 35%
Grid mode SUB/Solar First
Time to change 10:00 ANY SOC - to SBU


So - here's the issue ->

Change to SBU does not work - we have to set SBU mode manually every day.

The change back to Grid works fine and low voltage and low SOC also appears to work fine.


Any recommendations are welcome!

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On 2021/07/19 at 4:36 AM, David at SolutionCentre said:

2x Axpert 5kW  inverters

There are a lot of different models that fit the above description. I don't know the multiSIB software at all: are you able to tell/configure it for your exact inverter model? For example, Kings operate quite differently to other Axperts, as far as switching modes, and even what modes are available.

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Sorry - should have given model number! It is MKS-5K-B

I have been given some useful help by Yani who writes the MultSIB software.  Happy to share setup details.

The one remaining problem is that the system correctly swaps to GRID (USB) after using batteries at night, but then does not swap back to SBU mode in the morning.  I am trying to get the system to set higher priority for the battery than Utility, but the mode remains stuck in SUB (Solar-utility-battery).  I can manually switch to SBU but that means it would not automatically use batteries for the first part of the night.

You will note that the system is currently in SUB mode which happened at approx 8h10 when solar PV was enough to take over the load.

It would be nice for the system to be in SBU mode!

Has anyone else succeeded in an automatic switch to SBU??





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3 hours ago, David at SolutionCentre said:

The one remaining problem is that the system correctly swaps to GRID (USB) after using batteries at night, but then does not swap back to SBU mode in the morning.

This is all about the monitoring software then. I don't believe that these models have any sort of scheduling for output modes based on time. Some later models do, but I'm not sure that it works well, if at all.

As a point of interest (to me at least), what is the main (U1) firmware version?

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