Amp Hours vs Watt Hours Made Simple | Battery Basics | Ep 4/7
August 29, 2025 · 10 min · 59K views
What this video covers
Amp-hours (Ah) measure current over time, but watt-hours (Wh) provide the only accurate metric for comparing total energy capacity across different battery voltages.▶ 4:43 To calculate watt-hours, multiply the battery's amp-hour rating by its voltage.▶ 4:31 For example, a 100Ah battery at 12V provides 1,200Wh, while a 100Ah battery at 48V provides 4,800Wh.▶ 5:55 Because watt-hours represent the actual energy stored, they remain the constant factor when sizing a battery bank for specific loads, such as a 100-watt laptop or a 1,200-watt blender.▶ 9:45 Using amp-hours alone to compare batteries of different voltages leads to inaccurate capacity assessments, as higher-voltage systems store more energy at the same amp-hour rating.▶ 5:40 When designing an off-grid electrical system, determine total daily watt-hour consumption first, then size the battery bank to meet that demand.▶ 7:11 A general rule of thumb for recharging is to divide the total battery bank watt-hours by six to estimate the required solar wattage.▶ 8:46
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