Hello,
I have 2 MPPT 450/200 controllers with 4x 51.2 V Lithium NG batteries.
The charging in the bulk phase works up to approx. 95%, however, the MPPTs then regulate down and do not switch to the absorption phase.
What could be the reason for this?
Settings Lynx Smart BMS:
As you have the NG batteries and the Lynx NG BMS I also assume that you have a GX device like a Cerbo and they are all connected. The MPPT is therefore in external control from the BMS / Cerbo and will only show data for Bulk phase. My MPPT only shows bulk phase with the NG batteries.
Do not use that chart for seeing what the MPPT is doing, you have to look at the actual voltage history to see it swap from 14.0V to 13.7V.
Okay yes, I have an Ekrano GX, I’ll check that. But why isn’t the SOC (State of Charge) being set to 100%?
I have the 48V System.
Your batteries are full after 4 hours at 56.0V and the SOC should reset to 100%. I can not find an error in your settings, 56.0V charged voltage, 5.1% tail current and 3 minutes time should make the SOC reset to 100%. You could try setting the charged voltage at 55.8V, the tail current to 10% and the time to 1 minute (or 0 minute) to make it easier to reset to 100%.
What firmware are you running on the BMS. There was a firmware release (V1.13) in February 2025 and one of the fixes was to correct an error in the Amp hour counter, I have no idea if that could be a solution.
If you try the easier to synchronise settings and update the firmware if required and nothing changes then you may have a defective unit.
v1.13 – 17 February 2025
