Since early this year, I have a 12V, 140 AH AGM battery in my boat (VMF DC140-12 AGM).
On the battery, the following is specified:
"Charge voltage (25C) 14.6-14.8V (-30 mV/C), float use: 13.6-13.8V (-20 mV/C), max current 42A"
Whenever not sailing in the weekends, my battery was connected to shore power using a Victron IP67 12/17 charger, which I had set to the following 'advanced' settings in order to fully comply to the above specifications: Absorption charge: 14.7V, Float charge: 13.7V, Storage charge: 13.2V, Temperature compensation: -20 mV/C
After one season, my new battery is almost dead: only about 30 Ah capacity left. Not nice at all.
Did I do anything wrong? Is there a possible misunderstanding about the word 'Float Charge' (Victron: max 24 hours then storage charge, VMF: continuously after absorption charge)? Should I have set the 'storage charge' on the charger to 13.7V instead of 13.2 volt, so that it corresponds to the 'float charge' voltage on the battery? If that is the case, then that misunderstanding cost me a new battery.
What should have been the correct settings on my charger?
Below the definition of charge phases I believe Victron uses:
