SMA Sunny Island 6.0H-13 and Shuntmon2 HV 650V 50uOhm show different values

I have the following problem:
The SMA Sunny Island 6.0 can charge/discharge 4.6kW
When the battery is discharged, both the SMA and the shunt show the same value, maximum 4.6kW.
When charging, however, the shunt always shows a lower value, at 4.6kW only about 4.0kW. Always 10%-15% too low, regardless of the charging power.
This of course distorts the SOC, as the BMS cannot record this correctly.
Is there a solution, is the shunt defective? Is it possible to calibrate something?


Hi Michael,

Thanks for reaching out :slight_smile:

Could you share some more info on your system such as pictures of how it is laid out (focus on shunt and inverter), and a Manual Extract?

This will give us a better picture of what might be happening here. In general, do you notice an innacuracy around a certain range of current? or is it everywhere?

Keen to get to the bottom of this one with you!

Picture of loadout as attachment

the measurement is always wrong by about the same percentage, approximately 10-15%:

~4100W at 4600W
~2800W at 3000W
~1400W at 1500W

I can’t open the link, “Unauthorized” then “Invalid email / username or password.”


1 Like

Hi Michael,

Sorry about that dud link! I accidentally sent the link to the editor, as I was making some changes to that page. Here’s the correct one:

Please send that through to, your serial numbers are somewhat sensitive. I’ll update this thread when we solve it over there.