🔋 RC to Ah Calculator (Reserve Capacity to Amp Hours)
✅ Formula
Ah=60RC×25
Since Reserve Capacity (RC) is tested at 25 amps, we convert minutes to hours.
How to Convert RC to Ah (Step-by-Step)
- Take RC value in minutes
- Multiply by 25
- Divide by 60
Example Calculation
RC = 120 minutes(120×25)÷60=50Ah
✔ 120 RC ≈ 50 Ah
Quick RC to Ah Reference Table
| RC (Minutes) | Approx Ah |
|---|---|
| 90 | 37.5 Ah |
| 100 | 41.6 Ah |
| 120 | 50 Ah |
| 140 | 58.3 Ah |
| 160 | 66.6 Ah |
| 180 | 75 Ah |
🔄 Ah to RC Calculator (Amp Hours to Reserve Capacity)
Sometimes batteries list only Ah rating. To estimate RC:
✅ Ah to RC Formula
RC=25Ah×60
Example Calculation
Ah = 60 Ah(60×60)÷25=144minutes
✔ 60 Ah ≈ 144 RC
Quick Ah to RC Table
| Ah | Approx RC (Minutes) |
|---|---|
| 40 Ah | 96 RC |
| 50 Ah | 120 RC |
| 60 Ah | 144 RC |
| 70 Ah | 168 RC |
| 80 Ah | 192 RC |
Important Technical Note
These calculations are estimates because:
- RC is tested at constant 25A load
- Ah rating is usually based on 20-hour discharge rate
- Temperature affects performance
- Real-world loads vary
So RC ↔ Ah conversion gives an approximate comparison, not exact manufacturer value.
When to Use RC to Ah Calculator
Use conversion when:
- Comparing car battery capacity
- Replacing automotive battery
- Designing backup system
- Estimating emergency runtime
- Matching inverter battery size
RC vs Ah – What’s the Difference?
| RC | Ah |
|---|---|
| Measured in minutes | Measured in amp-hours |
| Automotive standard | General battery capacity |
| Emergency backup time | Total stored energy |
Final Summary
RC to Ah:
Ah = (RC × 25) ÷ 60
Ah to RC:
RC = (Ah × 60) ÷ 25
These formulas allow quick battery capacity comparison for automotive batteries.
