A normal parasitic draw is between 25 and 50 milliamps (mA). This covers the ECU standby, clock, alarm receiver, and key fob module. Anything above 75 mA is considered excessive and should be investigated. Above 300 mA is critical and will kill most batteries within days.
- Normal range: 25–50 mA (factory electronics only)
- Acceptable: 50–75 mA (with basic aftermarket accessories)
- Elevated: 75–150 mA (investigate the source)
- Excessive: 150–300 mA (no-start within 4–8 days parked)
- Critical: 300+ mA (no-start in under 4 days)
| Drain Level | Range (mA) | Days to No-Start (new 60 Ah, parked) |
|---|---|---|
| Normal | 25–50 mA | 25–50 days |
| Acceptable | 50–75 mA | 17–25 days |
| Elevated | 75–150 mA | 8–17 days |
| Excessive | 150–300 mA | 4–8 days |
| Critical | 300+ mA | Under 4 days |