Hi all. I have an inverter, the one mentioned in the post title(built by Sumry, the newest with parallel capability), and I noticed that the battery voltage displayed in the screen is different than the one indicated by BMS(55.2v displayed in bms vs 54.9v in inverter). This measurement was done with no loads. Is there any possibility to calibrate the voltage in this inverter? Thanks.

No one has any idea?

I have the same "issue", the inverter reads lower than the voltage monitor and multimeter. Logically, it would make sense for the BMS to read higher since there are no line losses, etc. But you are getting it during no-load conditions also. I wouldn't fret too much. You can go through the trouble of calibrating it, but mine has been running almost a year like that. I care about the voltage at the battery, not at the inverter.

My difference in reading is about 0.1 to 0.2V by the way. Whether under load or not.

I also don’t bother too much, currently I have set it up using user settings, but I need to set up the voltage in inverter to 54.9 v to correspond with 55.2 v in the battery. Unless I am able to set up the proper communication between inverter and bms, in this case it should read the voltage from bms and voila, problem solved. Currently, from time to time, the communication is lost for few seconds.

It's not trivial. I have a post about it here:

https://forums.aeva.asn.au/viewtopic.php?p=71631#p71631

5 hours ago, Coulomb said:

It's not trivial. I have a post about it here:

https://forums.aeva.asn.au/viewtopic.php?p=71631#p71631

Thanks for your reply. I see the post is for Voltronic inverters. SMG II is built by Sumry. Besides I have no idea if those commands will work, I don’t even have a pc application to issue those commands. I asked for one but Easun invoked things like it’s a service application only, technology secrets🙂.

On 2025/12/08 at 4:47 PM, Adrian79IS said:

I don’t even have a pc application to issue those commands.

There is a link to Voltronics' communications tool in the link; search for the keyword "tool" without the quotes.

On 2025/12/08 at 4:47 PM, Adrian79IS said:

SMG II is built by Sumry.

It's likely, but not definite, that Sumry is a reseller, getting Voltronic to manufacture the inverters with the Easun branding on it. Or perhaps Easun do that subcontracting, and Sumry are reselling the Easuns. That's Voltronic's chosen approach: let someone else deal with customer service. There are dozens of such resellers and brands, as well as many illegal copies.

The Easun SMG II models do look quite Axpert like, so the chances are good that this will work. Unfortunately, Easun seems to have started off as a clone manufacturer, so some of the older Easun models may not be genuine. But Easun have been around for many years now.