バッテリー寿命 計算ツール
容量と消費電流から動作時間を推定
Required Parameters
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Quick Answer
Estimated Runtime (Hours) = (Battery Capacity × Usable Efficiency) / Average Current Draw.
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瀹归噺(mAh)銇ㄣ儑銉愩偆銈广伄娑堣不闆绘祦(mA)銇熀銇ャ亜銇︺儛銉冦儐銉兗銇寔缍氭檪闁撱倰鎺ㄥ畾銇椼伨銇欍€?
鍩烘湰鍏紡
瀵垮懡(鏅傞枔) = 瀹归噺(mAh) / 璨犺嵎闆绘祦(mA)
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Design Notes
Battery capacity (mAh) is measured under ideal, low-current discharge conditions at room temperature. If your circuit draws high burst currents (like turning on a cellular modem or motor), the internal resistance of the battery causes a voltage drop (Peukert's Law effect for lead-acid, less severe but present in Li-Ion). Always derate heavily: a safe benchmark is using 80%-85% usable capacity for Li-Ion/LiPo, and as low as 60% for coin cells running high-pulse loads.
Common Mistakes
- 1
Assuming 100% capacity is usable: Most devices cut off when voltage drops below 3.0V-3.3V, leaving 10-20% chemical energy stranded.
- 2
Ignoring standby/quiescent current: A 100µA sleep current might seem small, but over months it completely drains a coin cell.
- 3
Not factoring in extreme cold, which can cut effective LiPo capacity by up to 40%.
Engineering Handbox
1. Calculate Usable Capacity: 2000 mAh × 0.85 = 1700 mAh 2. Divide by Average Load: 1700 mAh / 50 mA = 34 Hours
Knowledge Base
バッテリー寿命 = mAh ÷ mA で正確？
概算のみ。実際は自己放電、カットオフ電圧、ペウカート効果、温度で15〜30%減少。Li-Ion効率は80〜85%で計算。
計算にはどの電流値を使う？
ピーク電流ではなく、1サイクル全体の平均消費電流を使用してください。
mAhとWhの違いは？
mAhは特定電圧での容量。Wh = mAh × V / 1000 がエネルギー。異なる電圧のバッテリー比較にはWhを使用。
温度の影響は？
低温でLi-Ion容量低下：0°Cで-20%、-20°Cで最大-40%。最適動作温度：20〜25°C。
CR2032の寿命は？
約220〜240mAh。1µA連続で理論上約25年（棚寿命10年で制限）。10mAでは内部抵抗により大幅に低下。