1978 Evinrude Outboards 9.9/15HP Service Manual, Page 97Get this manual
CCapacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 80 (27 C)0 0
Terminal Voltage Test 1Variable Load High Rate Discharge Tester (Recommended) Connect tester to battery terminal postsDischarge at tate of three times battery ampere hour rating for 15 secondsIf the voltage is 9.6 volts or higher for 12-volt batteries at the end of 15 seconds, the battery has good output capacity2Fixed Resistance Tester This equipment has built-in load for high-rate discharge testing Follow equipment manufacturer's instructions regarding test period and meter readings3Engine Load For Resistance Disconnect wire connector between armature plate and power packConnect voltmeter across the batteryCrank engine for 15 secondsIf voltage is 9.6 volts or higher for 12-volt batteries at the end of 15 seconds, the battery has good output capacityBATTERY CHARGING Boost charge 12-volt batteries at 50 amperes for 20 minutes (1000 ampere minutes)If the charger will not give this rate, charge for an equal number of ampere minutes at best rate availableDO NOT boost battery more than this amount for the "light load test If batteries are to be fully charged by means of quick charger, the charge rate must be "tapered" (reduced to safe limit) when the electrolyte temperature reaches 125 (52 C), or when gassing becomes excessiveFailure to do so may harm the batteryIf the battery is to be slow charged, adjust electro-