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MPPT 100/50 Going to absorption too soon

Good day,

We have 3 x MPPT 100/50 connected all in parallel at a very short distance to the batteries.

We have 6 x Victron 200Ah LiFePO4 + BMS and Venus GX and 1000Amps smart shunt

Before solar will bring batteries to 100% but now batteries are at 80% and 9:30am with high sun the 3 MPPT's will go to absorption and charge goes to negative on the Shunt App.

Batteries are not full once stay over night running all lights and 3 fridges on a Lagoon 44 Catamaran.

Any idea why the MPPT's are going so fast to absorption without any other charger connected to the batteries.


Thanks for your help

MPPT SmartSolar
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Jesse avatar image Jesse commented ·

Have you tried measuring the voltage drop across the battery wires that connect the MPPT's when charging at full bulk current?

Are the MPPT's smart bluetooth devices, and connected together via VE.Smart networking?

Is there a bluetooth smart battery sense device included in the VE.Smart network? (or maybe it's not needed in your setup - Sorry, I'm not sure if the smart shunt can send voltage data via the GX? Might be worth comparing what voltage the MPPT's think the battery is at with what the other devices are measuring?)

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Mike Dorsett answered ·

Try checking the Absorption and float voltages and the absorption time. For lithiums, I would set the float voltage at about 95% of the Absorption voltage ( subject to manufacturer's data); so the Batteries stay at high SOC after reaching 100% on bulk. Also check stop after excessive bulk setting this should be about 4 hours.

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