question

This may be a silly question but do you have the BVM set to 400ah of capacity? And can you see the solar charging in the bluetooth app during day?

Also it would be good to know what you are powering and how many watts are leaving your batteries for that kind of drain.

(edited to reflect the correct 24v system) Thanks for correcting me, hate to give bad ideas to do checks from.

Maybe the (-) of the MPPT is connected directly to the battery instead of to the shunt "Load/Charger". So the charging current can't be measured.

@Cleaver he seems to have a 24V system so the capacity is 400Ah ;)

I am powering very little. A refrigerator and half a dozen light bulbs. I was not using a microwave, electric motors or television. The BVM is set at 400ah. I will check the wiring the next time I am up there. Initially there was a problem with the monitor wiring because I received the wrong set of wires from the factory. When I installed the correct wiring the monitor operated appropriately. The timing suggests a problem with the monitor. I had a problem getting the BVM to sync to my phone. A friend got the monitor to sync a couple of weeks ago but when I started to use the bluetooth the readings dropped from fully charged down to 9.5 within three days even though it was sunny and very little drain on the batteries. The person who got the bluetooth to sync was told not to make any changes to the settings. When I left, the system was still operating but the readings were continuing to drop. When I go back I assume the system will either be operating or I'll have melted ice cream on the kitchen floor. I'm hoping the issue is with the monitor and not something more serious. Thank you for your interest.