Jump to content

BAK 48V 5Kw Lithium Battery Values


Recommended Posts

Hi There


I have the 5Kw Axpert King with a BAK 48V 5Kw Battery.

My SOC on the inverter does not closely represent what the LED on the battery shows. With the battery showing full the inverter still shows 60%.

The supplier recommended the following settings:

Cut off voltage: 48V

Bulk Charging: 56V

Float Charging: 55V

Has anyone had experience with this battery and voltages for it ?





Link to comment
Share on other sites

Hi @Pierreh,

Your BAK battery is quite a beast.!

However, as it (and many other batteries with BMS's) does not "talk" to the King, even though both the King & BAK can "talk".(but not necessary to each other in an understandable way)

You see, what we have here is a classical "Tower of Babilon" scenario. Every Inverter and every Battery Manufacturer  uses it's own protocol to communicate the salient values of battery voltage, SOC etc. Whereas the protocol is either CAN bus or (mostly) RS485, the data contained does not always match (or line up).

So Battery Manufacturer1's put SOC in the 1st field, and Battery Manufacturer2 put the same data in the second field, and so the lines are crossed. BMS merrily send data (once the RS485 comms is established), but the Inverter does not respond correctly (because it is expecting SOC in the 3rd field), due to the Babilon effect.

Unfortunately, as more and more BMS manufaturers sell into the market, more and more different combinations are created, and the poor man with solar system get's left behind.

So AFAIK, the King does have support for Li batteries, and Pylontech does seem to be (hopefully properly) intergrated. 

You can try and follow the same procedure and you may be damn lucky to get it going, so do try and post your result/effort here.

By using "USE" setting, the basic problems of SOC readings not matching will appear. (Documented frequently here on this forum) I would trust the BAK's view on this anytime. 

For prospective solar installations, I would very carefully check which inverter is compatible with which battery. 

Unfortunately, Voltronics is already a bit late to this party, and I had hoped that ICC would fulfil that Gateway roll, as it does today with older Axperts and Pylontech, it still is not everybody's cup on tea, as it does add to the existing complexity. 

My ideal (next) setup would be  Inverter - RS485 port - RJ45 Cable - Rs485 port - Battery. Plain and simple

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...