Hi All

I have a Kodak king 5.48 , connected to it are 12 x 455w Canadian solar panels and 3x Hubble am-2 lithium batteries . I use a raspberry pie with icm software to monitor the system . My issue is this , since I added my 3rd Hubble am-2 battery I have noticed the following . 
When I look at my monitoring software I can see my batteries are at for eg: 50v ( this is confirmed by my bms Hubble cable connected directly to the master Hubble battery ) but when I look on my inverter values page the inverter is reading the battery voltage at 48v for example . It’s always a lot lower than what my batteries actual values are . So my inverter reads the voltage from the battery at 44v then starts charging the batteries , but the batteries are actually at 46v so I’m loosing out on battery power and using eskom . 
My 3 Hubble batteries should get me through the night but now the inverter starts to charge the batteries prematurely due to it reading incorrect voltage from batteries . Please advise if you have any thoughts .

Edited April 2, 20231 yr by Richard White

If your display (U2) firmware is 02.xx, then a colleague and I are developing patched display firmware that can help.

We're actually developing and testing it on a King (=OG+ 5.48), but the display firmware seems to be the same for OG and OG+ models. This firmware "passes through" two commands that make it much easier to adjust the battery voltage reading calibration.

We haven't released this firmware as yet, since it doesn't do much other than pass through these commands as yet, but we could make an early release of what we have if you are interested.

Details on using these two commands (BTA and PSAVE) are in this post. If that's all Greek to you, we won't bother with an early release. But if you are able to take advantage of it, we'd be happy to do it.

Just reply below if you are interested.

Hi @Coulomb

Yeah , unfortunately I don’t really understand the Greek language . Attached is the log info of my inverter . Will updating software on my inverter fix any issues I currently have ?

question : if i change the cut off voltage from 44v ( currently ) to 42v will that help in any way , seen as though at 44v the battery is actually around 46-47v ?

is this a common problem with these inverters ?

once you release the software , how can I get it and is there a guide for how to update the inverter software . I do have the cable so I can update it myself . 
thank you for the info . 

5 hours ago, Richard White said:

Will updating software on my inverter fix any issues I currently have ?

it will enable you to type some relatively simple "Greek" and fix your problem. Otherwise, you need complicated Greek.

5 hours ago, Richard White said:

question : if i change the cut off voltage from 44v ( currently ) to 42v will that help in any way , seen as though at 44v the battery is actually around 46-47v ?

That's a potential work-around, especially short term. But reading the wrong battery value will have many effects; it would be much better to correct the problem.

5 hours ago, Richard White said:

is this a common problem with these inverters ?

It's happened to one of my pair, and to the King inverter we use for testing the patched firmware. So yes, it does seem to be relatively common. I don't know why it's happening.

5 hours ago, Richard White said:

once you release the software , how can I get it

There will be a web page on it, and I'll post a link to that page. You download the attachment to that link, and follow the instructions on another page to do the actual update. The update itself takes about 10 minutes, and during that time the display won't work but the inverter can continue running.

5 hours ago, Richard White said:

is there a guide for how to update the inverter software .

Yes. here

5 hours ago, Richard White said:

I do have the cable so I can update it myself . 

Good. Hopefully you mean the USB to serial adapter that is required, and hopefully it's one of the known compatible ones.

I'll do a little tidying up and do the release.

Thanks . What does the software actually do , does it automatically fix the under / over reading of the battery voltage ?

I thought it was usb to Rs232 cable , so no , I don’t have that cable . Any link to where I can buy it from , or once you release software is there anyone available that can actually update it for me ?

On 2023/04/02 at 5:44 PM, Richard White said:

once you release the software , how can I get it

Lightly patched display firmware for Axpert King and Axpert MKS III has been released:

https://forums.aeva.asn.au/viewtopic.php?p=95822#p95822

[ Edit: Where are my manners? A huge thank you to user @Youda who made this research possible with his generous donation! ]

@Richard White let me know if you need assistance updating the firmware, or using it to calibrate your battery voltage.

Edited April 4, 20231 yr by Coulomb

Hi @Coulomb

Many thanks for this . As i only understand the basics of the solar world , let me ask you these questions if i may , and i will require , if possible a lot of assistance .

Connect the USB-to-RS232-serial adapter to the RS232-serial-to-RJ45 cable that came with your inverter-charger

Does this mean i need the cable that came with the inverter and a USB to serial adapter , then connect the 2 cables together ?

Once the update is done , what do i need to change on my ICM software in order to get the voltages correct ? Also i notice that my inverter over reads when charging and also under reads when discharging , do we / can we change both to get the correct settings ?

 

 

 

2 minutes ago, Richard White said:

Connect the USB-to-RS232-serial adapter to the RS232-serial-to-RJ45 cable that came with your inverter-charger

Does this mean i need the cable that came with the inverter and a USB to serial adapter , then connect the 2 cables together ?

Yes. The two 9-pin connectors should be male and female, and they should connect together.

2 minutes ago, Richard White said:

Once the update is done , what do i need to change on my ICM software in order to get the voltages correct ?

Unless you have extremely enlightened monitoring software, you won't be able to do it from there. You have to unplug that software (assuming it's using the "PC" port on the display), and plug your computer to the removable display. On the computer, you need to run some free communications software; I always use TeraTerm, but there re many others. Set it up for 2400 bps (this is very slow compared to most serial communications). Once set up, you type commands into the comms program, and the inverter responds with "ACK" (good, command received), or NAK (bad, command not understood or the parameters are wrong). You send a series of such commands; each one should nudge the battery reading in the correct direction (read higher or read lower), until you're happy with it. At that point you send the PSAVE command to make the calibration permanent. You do all this battery calibration with very light loads and no charging.

7 minutes ago, Richard White said:

Also i notice that my inverter over reads when charging and also under reads when discharging , do we / can we change both to get the correct settings ?

That's because of the internal resistance of the battery, and the resistance of the battery cables. There isn't much you can do about that, apart from using thicker cables between the battery and the inverter(s). To minimise this effect when calibrating, you do the calibration with very light loads and no charging, minimising this effect. In effect, you want to get the average between charging and discharging as close as you can.

Ok , i`ll need to find my inverter cable .

2 hours ago, Coulomb said:

Unless you have extremely enlightened monitoring software, you won't be able to do it from there. You have to unplug that software (assuming it's using the "PC" port on the display), and plug your computer to the removable display.

what cable do i use to connect my computer to the inverter and into which port on the removable display do i plug that cable into .

2 hours ago, Coulomb said:

Once set up, you type commands into the comms program, and the inverter responds with "ACK" (good, command received), or NAK (bad, command not understood or the parameters are wrong). You send a series of such commands; each one should nudge the battery reading in the correct direction (read higher or read lower), until you're happy with it. At that point you send the PSAVE command to make the calibration permanent. You do all this battery calibration with very light loads and no charging.

What are these commands i need to type in and what is PSAVE command ?

 

2 hours ago, Coulomb said:

Unless you have extremely enlightened monitoring software, you won't be able to do it from there. You have to unplug that software (assuming it's using the "PC" port on the display)

My raspberry pi is connected to the port with the usb image ( image attached ) 

12 hours ago, Richard White said:

what cable do i use to connect my computer to the inverter and into which port on the removable display do i plug that cable into .

As it says in the upload instructions, you need a USB to serial adapter, like this one:

http://forums.aeva.asn.au/uploads/689/USB_to_serial.jpg

You plug the 9-pin end into the cable that came with your inverter, the other end of that goes to the PC port (on the right, red plug in your photo).

12 hours ago, Richard White said:

What are these commands i need to type in and what is PSAVE command ?

You will type in a series of BTA commands, as per the post. There are two commands, one nudges the reading up, the other nudges the reading down. You repeat the commands until the reading  agrees with that of a multimeter.

Then you use the Parameter SAVE command (PSAVE), which writes the calibration value (currently in volatile RAM) to EEPROM, so the next time you power up the inverter, it remembers the calibration you did.

Quote

My raspberry pi is connected to the port with the usb image ( image attached ) 

For the duration of the calibration, you should probably disconnect the Raspberry Pi. There is some chance that it may be sending commands that would interfere with the calibration. It may be possible to use the USB port to send commands; I've never done it that way, and I would not know how to set up a comms program to talk to it.