We have 900 w of 5 solar panels divided into two sections 3 in front and 2 at rear of van roof. 400ah lithium (2x 200ah)
Have had two 100/50 solar controllers installed 2 days ago.
I do not understand why the front panels (Zone 1) shows 275w on float and the rear panels (Zone 2) shows 39w on float? Sometimes Zone 1 can be 594w and Zone 2 139w. Zone 1 is always way higher. At present batteries are at 100% but this difference is always the same. Whether the batteries are lower or not. The panels are in full sun and were cleaned yesterday
Have you set them up in a VE Smart Network to synchronise charging. Do you have a SmartShunt or Battery Sense measuring battery voltage.
If the 2 units are completely independent then one MPPT will always lead during absorption and float when voltage is being controlled. To explain, the MPPT will bevset to say 13.5V float and this is measured on the output of the MPPT. You will have slightly different voltage measurement accuracy on the 2 MPPTs, maybe only 0.01V different but that is enough to make one more likely to charge. Add in the fact that you will also have voltage losses in your cabling, switches and fuses that are unlikely to be the same adds to this effect.
During float the battery wants limited charge current and you will mainly be supplying loads so you will still harvest enough power, just not equally from the 2 MPPTs.
To try and even them up, set up synchronised charging in a VE Smart Network. Covered in the manual.
No none of the things you mentioned in your first paragraph.
Understand a bit more now so thank you for taking the time to explain, appreciated.