January here is not a Minnesota winter
Gainesville and Ocala get cool nights, not months of hard freeze. The failure we see in winter is a battery that sat discharged in a garage or on a trailer after deer season, not ice in the cells. Battery University’s storage and sulfation notes still apply in north-central Florida: lead-acid that sits low loses capacity. A tender through the cooler months is maintenance, not a ritual pour-out of antifreeze.
Keep flooded cells full and charged
BU-403 says to store lead-acid charged. Check water on flooded batteries before a storage charge. A pack that went into Thanksgiving already low will not be rescued by a one-hour trickle in March. AGM does not get water; it still wants a correct AGM storage voltage, not a flooded equalization left on for weeks.
Lithium in a cold garage
LiFePO4 does not sulfate the way lead does, but some BMS units refuse to charge near freezing. A trailer in Alachua that sat through a rare cold week can show a “dead” lithium that is actually charge-inhibit. We read the module sheet. We do not assume every Florida morning is 70°F in the garage.
Boats that still run in winter
Plenty of owners fish through January. Those batteries need the same charger discipline as in May, plus a look at parasitic draws — a stereo memory, a pump float — that nibble a bank that is no longer getting daily sun on a lift. Winterizing here often means “stay in service on a tender,” not shrink-wrap.
What we do on a winter visit
Load-test or rest-voltage after the pack has sat, check water if flooded, and set a charger that matches chemistry. If the boat will sit until spring, that is the off-season storage article — a different job from keeping a working boat ready on a cool weekend.
Cool mornings and parasitic draws
A stereo that nibble-drains all week is worse in January because you may not run the boat enough to refill. A tender on the correct chemistry through the cool months is the working-boat version of winterizing here. If the hull is shrink-wrapped and will not move until March, that is off-season storage — a different article, a different charger schedule.
Sources
- Battery University BU-403 — Charging Lead Acid
- Battery University BU-802 — What Causes Capacity Loss
If this is the job on your boat, see how we replace batteries at the boat. We come to you — Florida towns and counties.