You can try this version:
Marstek Energy Storage | Homey
It has the two registers now exposed as max limits capabilities.
I did some tests, the values doesn’t change. It stays always 2500W.
I have seen that sometimes the actual maximum charging power goes down to 500W. (depending of temperature and SOC)
I asked to marstek if there are some registers to read out the actual maximum charging/uncharging power. But the answer is No. There is no possibility to read this out by modbus. The Venus limits this internal.
I check if i can build a flow that detects the actual charging and uncharging power.
Thanks for the support!
to bad 
What is it supposed to do?
This function in the Martek app allows me to determine how far the battery can be discharged. Currently, I have it set to 50% so that I have 50% left in case of a power outage. However, if the battery is at 50% and the power goes out, the battery behaves as if it’s empty, and the backup outlet switches off. I now have to manually adjust this setting to a lower value in the Martek app so that the backup function works again. I’d like to automate this with Homey. IF: mains power is absent THEN: set DOD (dept of discharge) to 12%.
Check, I played with that one on the modbus already, so yes I believe that should be possible. Ill add it to my list. My problem with it indeed is the fact it turns of the backup socket if it goes below. So I decided to make a flow, if goes below 50% set force mode and set force target to 50%.
If the power is out, the socket remains active, even though it tries to charge it can not, nce the power s back it fills to 50% again. Once I am there I switch it back to normal operation.
Thanks for the answer. Can you share your flow with me please?
Since I use my self build EMS Homey App to interact with the battery you cant use my flow.
But the concept is:
When battery soc < variable value I set to 50%, the set mode to use force controls, then set force to soc 51% and again to force soc 50%
This triggers charging that stop at 50%
Another trigger when soc > 49% switch to mode you want based on other conditions
Thanks! I’ll try to make a nice flow
I am releasing a new version of the app that allows these settings to be set (did not test them myself) through the device settings and flows.
I also added a test page to the app settings allowing advanced users to retrieve register info from the modbus and do manual tests (Writing to registers may harm your device!!!)
Also some stability improvements.
I’ll check it out 
new test version has a fix, forgot to set it in control mode before write
Don’t know what i am doing wrong then.. Can’t get it to work.
You tried the test version? Not sure if the new version was already approved by homey
I’ll try again tomorrow. Thank you!
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It could be that i’m doing completely wrong but i can’t get it to work.
How should a flow look like?
What feature are we now referring to?
The card to set maximumdischarge level or the soft limit discusses earlier, the card just sets the battery setting. So a hard minimum.
The soft one is how I described it above. This card is not soft minimum.
