question

scoraigwind avatar image
scoraigwind asked

Smartsolar falsely reports PV voltage lower than battery

A customer installed a Smartsolar 150V MPPT on a 48V BYD battery system and after maybe five days something happened to the controller so it decided the PV voltage was only 45V instead of 120V. What is most strange is the way it sometimes has a good PV current when the PV voltage is lower than battery voltage. This does not seem possible. But mostly it has poor output (or none) and I am wondering what is causing this anomaly?


Below is a picture of the day when it started to misbehave. Multimeter readings of the PV input voltage show Voc over 100Vdc when the VRM and the Victronconnect are showing 45Vdc on the PV input. Battery voltage reported to VRM is still correct.

whatsapp-image-2023-01-31-at-141637.jpeg

MPPT ControllersVRM
whatsapp-image-2023-01-31-at-141637.jpeg (133.2 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Paul B avatar image
Paul B answered ·

Check to make sure that the MPPTs system voltage setting is correct and set to 48v.


also check for volt drop over the PV fuse or breaker, maybe remove it for a test.

recheck the pv voltage at the regulator terminals

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

scoraigwind avatar image scoraigwind commented ·
Thanks, yes we have checked these. Set for 48V, yes. It was working well for a few days. Voltage has been tested at the input terminals and it does not accord with the PV voltage reported to VRM.
0 Likes 0 ·