Flow of Diagnosis

A. Testing battery charge

General
- Make sure that battery poles and leads are free from dirt and that the leads are correctly secured. Dirt causes an increase in resistance which in turn causes a loss of power.
- To help prevent sparking when removing a battery, always disconnect the negative battery lead first. Connect the positive lead first when installing a battery.
- Smear battery poles (clamps) with acid-resistant grease (P/N 1161 150-6) after securing the clamps.

Testing battery

A1 Check battery charge

NOTE: Do not measure the specific gravity of the electrolyte if you have just added distilled water. The battery must be charged for a couple of hours first.

Measure specific gravity of electrolyte in all the cells, readings as followed:

1.280 Is Fully Charged:

State of charge Specific gravity at 20 °C
Fully charged 1.28
Half 1.21
Discharged 1.13
If one or more cells are less than 1.28 proceed to A2
If all cells are less than 1.28 charge battery, see A3

A2 Testing battery under load





Conditions: temperature approx. 15 °C (60 °F), battery fully charged, engine cold. Remove cell caps from battery. Disconnect (-) lead from ignition coil. Connect voltmeter (range 0 - 40 V) as shown. Operate starter motor for 10 sec:

If voltage drops below 9.5 V and/or air bubbles are present in one or more cells, install new battery and retest. If voltage is 9.5 V or higher, battery OK*
* Reconnect lead to negative terminal of ignition coil.

Charging battery

WARNING! An explosive gas is produced during and after charging. Ensure that work area is adequately ventilated and avoid naked flames and arc welding. Turn off battery charger before removing terminals.

A3 Charge battery





Remove filler caps from cells. Check electrolyte and top-up if necessary with distilled water. Charge battery for 10 hours at recommended current. Recommended charging current = 0,1 X battery capacity.

Example: Capacity = 55 Ah. Recommended charging
current = 0.1 x 55 = 5.5 A.

Measure specific gravity of all cells after charging battery. Max. difference between cells = 0.03.