Battery, energy & solar
Battery Bank Calculator
Series batteries add voltage while parallel strings add amp-hour capacity. Total nominal energy equals bank voltage multiplied by bank amp-hours.
Calculate series/parallel battery quantity, bank voltage, amp-hours, and watt-hours from unit specifications.
Calculated result
Battery bank totals
Calculating…
Calculated locally in your browser
Planning math only. Verify equipment specifications and installation requirements separately.
What this calculator returns
Use identical compatible units and follow manufacturer requirements for series/parallel connection and protection.
Formula and variables
The calculation runs entirely in your browser. Static formulas, definitions, examples, and tables remain readable without JavaScript.
Vbank = Vunit × series; Ahbank = Ahunit × parallel; Whbank = Vbank × Ahbank.
- V
- Nominal battery or bank voltage.
- Ah
- Charge capacity in amp-hours.
- Wh
- Nominal or usable stored energy in watt-hours.
- W
- Average load power in watts.
- η
- Entered conversion efficiency.
Total quantity equals series count times parallel-string count.
Worked example
| Input | Value |
|---|---|
| Unit voltage | 12 V |
| Unit capacity | 100 Ah |
| Units in series | 2 |
| Parallel strings | 2 |
| Result | Four 12 V, 100 Ah batteries arranged 2S2P create a nominal 24 V, 200 Ah, 4.8 kWh bank. |
Four 12 V, 100 Ah batteries arranged 2S2P create a nominal 24 V, 200 Ah, 4.8 kWh bank.
Reference table
| Appliance | Planning watts | Use note |
|---|---|---|
| LED lamp | 10 W | Nominal example |
| Laptop computer | 60–120 W | Typical planning range |
| Refrigerator while running | 100–250 W | Cycling load; startup can be higher |
| Microwave oven | 900–1,500 W | Input varies by model |
| Portable space heater | 1,500 W | Common high setting |
| Electric kettle | 1,200–1,800 W | Varies by market and model |
Frequently asked questions
Is this battery-bank result code compliant?
No. PowerTotals performs transparent electrical math and planning estimates. Installation decisions must be checked against equipment documentation, the adopted code, and the authority having jurisdiction.
Are my inputs uploaded?
No. Calculations run locally in your browser, and analytics never receives raw electrical values.
Assumptions and limitations
- Nominal energy only.
- No charging, BMS, conductor, fuse, or chemistry safety recommendation.
Method and sources
Read the calculation methodology, review the technical sources, or browse the reference table index. Last reviewed .