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Guide

Wh to Ah Converter

Wh to Ah converter: divide watt-hours by system voltage for amp-hours—size battery banks from energy budgets, match Wh-rated loads to Ah-rated packs.

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Energy targets often arrive in watt-hours; battery shopping lists amp-hours. This guide walks through the Wh to Ah converter: your Wh budget, nominal bus voltage, and equivalent amp-hour capacity.

Benefits

  • Core formula: Ah = Wh ÷ V.
  • Works backward from solar yield, load budgets, or inverter autonomy targets.
  • Pairs with Ah to Wh for round-trip battery sizing checks.

How it works

  1. Enter your energy target in watt-hours (Wh)—daily load, bank size, or pack rating.
  2. Add nominal system voltage (12 V, 24 V, 48 V, etc.).
  3. Read equivalent amp-hours (Ah) for bank or pack selection.

FAQ

How do I convert Wh to Ah?

Ah = Wh ÷ V. Example: 1,200 Wh at 12 V → 1,200 ÷ 12 = 100 Ah. The same 1,200 Wh at 48 V needs only 25 Ah—higher voltage means fewer amp-hours for the same energy.

When do I need Wh to Ah instead of Ah to Wh?

Use Wh to Ah when you start from an energy budget—daily watt-hour load from appliances, solar production in Wh, or inverter runtime math—and need to shop for Ah-rated batteries at your bus voltage.

What voltage should I use?

Use the nominal voltage your loads and inverter connect to—12 V RV, 24 V marine, 48 V off-grid, or 12.8 V LiFePO4 nominal. Marketing cell voltage (3.7 V) is for single cells, not finished 12 V packs.

Technical specifications

  • Ah = Wh ÷ nominal_V.
  • Wh = Ah × V (reverse check).
  • kWh → Wh: multiply by 1,000 before dividing by V.
  • Related: wh-to-ah, ah-to-wh, battery-bank-size, battery-runtime.

Energy budgets speak Wh; battery labels speak Ah

You calculated 2,400 Wh of daily off-grid load, or a 5 kWh solar battery spec lists energy—not amp-hours at your voltage. Dividing Wh by your 12 V, 24 V, or 48 V bus converts that energy target into the Ah number on deep-cycle datasheets. Without this step, you risk undersizing a bank that looks big in Ah at the wrong voltage.

Higher voltage means fewer amp-hours

1,200 Wh is 100 Ah at 12 V but only 25 Ah at 48 V—same stored energy, different amp-hour sticker. The Wh to Ah converter keeps voltage explicit so a 48 V quote is not compared to a 12 V Ah listing by mistake. Always enter the voltage the bank will actually run at.

Round-trip with Ah to Wh before you buy

Convert Wh → Ah to shortlist packs, then Ah → Wh on each candidate to verify nameplate math matches your budget. Add depth-of-discharge and efficiency after rated Ah—this tool gives nominal capacity equivalence. Follow with Battery Bank Size or Runtime when you need hours of autonomy at real loads.