The numbers on BU-409b
A 12-volt LFP pack is four 3.2-volt cells. Battery University BU-409b describes an LFP charge program around 14.6 volts with no float. We still follow the module maker’s profile for the pack in the tray. A leftover lead-acid charger program is not that profile. A BMS may disconnect on overvoltage; that is protection, not a charge algorithm. If the slip charger cannot be set for lithium, the charger is on the quote.
Per-bank settings on bass boats
A three-bank unit with one chemistry brain cannot float a flooded starter correctly and also stop lithium trolling at 14.6 without a profile per bank. Mixing those chemistries on one brick is how one side suffers. Separate chargers, or a unit that can assign profiles, are the options we discuss.
Temperature and the BMS
Some modules refuse to charge when cold. Some shut down when hot in a furniture box. The charger can be perfect and the BMS will still open. We read the sheet for that module rather than assuming a generic lithium rumor.
Alternator path
If the engine also charges the lithium bank, the alternator article applies. The BMS and a DC-DC or isolator are the adult hardware. We will not tell you the BMS makes a small outboard safe on a large empty bow.
Cape Coral and tournament bows
Lift-kept house lithium and driveway trolling lithium are both this charger conversation. Bring the charger model and the module label. We match them on the boat.
What “the BMS will take care of it” misses
A disconnect on overvoltage protects the cells and can still leave the charger or alternator in a bad state. We want a charger that already stops at the LFP window so the BMS is backup, not the daily regulator. If the only charger on the boat is a flooded three-bank brick, the brick changes with the modules. That is the visit, not a firmware hope.
Sources
If this is the job on your boat, see how we replace batteries at the boat. We come to you — Florida towns and counties.