Want to make your battery last longer? Understanding and tracking Depth of Discharge (DoD) is a smart move — and our handy calculator makes it easy!
Whether you’re using batteries for solar power, RVs, off-grid systems, or backup storage, knowing how deeply you’ve discharged your battery helps you extend its life and optimize performance.
Table of Contents
🙋 What is Depth of Discharge (DoD)?
Depth of Discharge tells you how much of your battery’s capacity has been used — expressed as a percentage.
For example:
- If you have a 100Ah battery and use 40Ah, your DoD is 40%
- The remaining 60% is called State of Charge (SoC)
Every battery has a recommended DoD limit, and going beyond it can reduce lifespan.
📉 Why Track DoD?
Tracking DoD helps you:
- Prevent over-discharge
- Extend battery lifespan
- Choose the right battery size
- Monitor energy consumption accurately
For example, lithium batteries can handle 80–90% DoD, but lead-acid batteries are best kept under 50% discharge.
🧮 DoD Formula
The formula to calculate Depth of Discharge is:
DoD (%) = (Energy Used ÷ Total Battery Capacity) × 100Both values should be in amp-hours (Ah).
✅ Example
You have a battery rated at 200Ah, and you’ve used 60Ah:
DoD = (60 ÷ 200) × 100 = 30%That means your battery is 30% discharged and still has 70% left
📊 Typical DoD Guidelines by Battery Type
| Battery Type | Recommended DoD (%) |
|---|---|
| Lead-acid (flooded) | 50% or less |
| AGM / Gel | 50–70% |
| Lithium-ion (LiFePO₄) | 80–90% |
| NiMH / NiCd | 80–100% |
📌 Final Tips
- Never fully discharge a lead-acid battery unless you want to replace it soon
- Use a battery monitor or this calculator regularly to track usage
- For off-grid or solar setups, size your battery bank so you stay within safe DoD limits
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