Onboard Charger Sizing at Every Bank Size

Charger output per bank by capacity and chemistry, and how long a real recharge takes.

Every page below is computed rather than written, from the same formulas the matching calculator uses, so a figure on a chart page and the same figure in the calculator cannot disagree. Each one carries its working, the basis of every number it prints, and gear chosen by those numbers rather than from a general list.

• What size onboard charger does 1 bank of 50 Ah need? Charger output per bank for a 50 Ah battery across 1 bank, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 2 banks of 50 Ah need? Charger output per bank for a 50 Ah battery across 2 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 3 banks of 50 Ah need? Charger output per bank for a 50 Ah battery across 3 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 1 bank of 75 Ah need? Charger output per bank for a 75 Ah battery across 1 bank, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 2 banks of 75 Ah need? Charger output per bank for a 75 Ah battery across 2 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 3 banks of 75 Ah need? Charger output per bank for a 75 Ah battery across 3 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 1 bank of 100 Ah need? Charger output per bank for a 100 Ah battery across 1 bank, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 2 banks of 100 Ah need? Charger output per bank for a 100 Ah battery across 2 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 3 banks of 100 Ah need? Charger output per bank for a 100 Ah battery across 3 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 1 bank of 120 Ah need? Charger output per bank for a 120 Ah battery across 1 bank, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 2 banks of 120 Ah need? Charger output per bank for a 120 Ah battery across 2 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 3 banks of 120 Ah need? Charger output per bank for a 120 Ah battery across 3 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 1 bank of 150 Ah need? Charger output per bank for a 150 Ah battery across 1 bank, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 2 banks of 150 Ah need? Charger output per bank for a 150 Ah battery across 2 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.
• What size onboard charger does 3 banks of 150 Ah need? Charger output per bank for a 150 Ah battery across 3 banks, in lead acid and lithium, and how long it takes to put back what a day on the water used.

Researched, not professional advice. Every figure on these pages is labelled as a published engineering or manufacturer figure, a rule of thumb, or something that only exists on your own boat. Where a published figure does not exist we say so rather than estimating one. The capacity plate on your boat, the manual for your own equipment and ABYC E-11 for anything electrical are what govern.