TLDR:Current Output current data from MPPT controller is around 30% higher than SmartShunt current data
Hi, I am relatively new to the use of Victron products and recently upgraded my solar charge controller to a Victron MPPT 75/15 and installed a SmartShunt in my campervan. The reason for the upgrades was to enable me to manage the power usage of my leisure battery while I am away, I love the products I think they are great.
The setup I have is a small portable 100w panel from Renogy which is connected to the MPPT the negative output from the MPPT is connected to the load terminal on the SmartShunt, the terminal labelled battery on the SmartShunt is connected to the negative post on the Battery (105 Ah). The positive output from the MPPT is connected to the positive post on the battery.
All of the equipment and battery are stored within the same space and are connected using small cables of the correct rating for the maximum current.
I have included a couple of screenshots taken within the same minute using the IOS app showing the difference in data between the two devices. It is difficult to get an exact snapshot due to having to switch between the devices within the app but the output from the MPPT has been consistently the same for around 15 minutes as has the reading on the SmartShunt. There is no current being drawn from the battery - verified by disconnecting the panel and checking the data on the Shunt.
I don't have a clamp meter to check the actual current on the MPPT output cable and I thought before I go an buy one I would post on here.
I have tried changing cables and using a different battery / solar panel but consistently see the numbers are around 30% different between the two.
The settings on both devices are basically factory defaults, I changed the charged voltage on the smart shunt to 13.6 volts and the tail current to 1.5 with an 8 minute detection as the shunt kept setting the SOC to 100% despite the MPPT being in the absorption stage. Changing these settings has no impact on the detected current.