Battery Calculator

Marine Battery Runtime, Health & Charger Sizing Calculator

Step 1: Select Marine Equipment & Calculate Load

Available Equipment

Custom Amperage (Amps)

Selected Equipment & Load

Equipment	Amperage (A)	Action
No equipment selected
Total Load	0.0 A

Step 2: Enter Battery Information

Battery Voltage

Battery Capacity (Ah) Amp-hours of battery bank

Battery Health (%) Current condition (100% = new)

Safe Usage (%) Recommended: 80% for lead-acid, 90% for lithium

Charger Voltage

Desired Charge Time (Hours) How long to fully charge

Calculation Results

Runtime Until Empty

Hours

Charge Time Required

Hours

Battery Health Status

Status

Usable Capacity

Required Charger Size

Amps

Recommended Charger

Model

Suggested Battery Quantity

Batteries

Battery Configuration

Series/Parallel

⚠️ Important Notes:

Battery health status based on current condition
Charger size calculated for optimal charging
Always consult with a marine electrician for final installation
Battery recommendations are estimates based on typical usage patterns

Battery Runtime

Runtime is calculated by dividing usable battery capacity by the total load current. This gives you an estimate of how long your battery will power your equipment before being completely discharged.

Formula: Runtime (hrs) = Usable Capacity (Ah) ÷ Load (A)

Battery Health

Battery health indicates the current condition of your battery bank. New batteries are at 100%, and health decreases over time due to age and usage. A battery below 70% health should be considered for replacement.

Status Guide: 90-100% (Excellent), 70-89% (Good), 50-69% (Fair), Below 50% (Poor)

Charger Sizing

The charger size is calculated based on your desired charge time and battery capacity. A larger charger will charge your battery faster, but may require more shore power infrastructure.

Formula: Charger Size (A) = Battery Capacity (Ah) ÷ Charge Time (hrs)