Battery Voltage Test (Sealed Batteries Only)

(Engine not running)

- Switch headlights and high beams on for 1 minute to remove surface charge.
- Disconnect Battery Ground (GND) strap.
- Check Battery Positive Voltage (B+) using Sun VAT 40 or equivalent.
Specification: 12.4 volts minimum

Voltage % charge
12.6 or more 100%
12.4 75%
12.2 50%
12.0 25%
11.7 or below 0%

If above minimum voltage:
- Load test battery.

If below minimum voltage:
- Charge battery (12.4 volts minimum) See Service and Repair/Battery, Charging

Load test


NOTE: Before load testing, the battery must be at least 75% charged.


- Connect load tester (Christie Automotive BT-900 or equivalent) according to manufacturer's instructions.
- Load battery to:
- 3 x amp/hour rating, or
- One-half cold-cranking current rating at 0 °F
- Wait 15 seconds.
- Read voltage.
Specification: 9.6 volts minimum (at room temperature)

If specification is not reached:
- Replace battery.


NOTE: If battery is colder than room temperature, voltage under load will be lower.


If battery must be tested cold, use the chart below to determine whether the battery passes the load test:

Approximate electrolyte Minimum acceptable voltage
temperature °F ( °C) under load (volts)
60 °F (16 °C) 9.5
50 °F (10 °C) 9.4
40 °F ( 4 °C) 9.3
30 °F (-1 °C) 9.1
20 °F (-7 °C) 8.9
10 °F (-12 °C) 8.7
0 °F (-18 °C) 8.5