How To Tell If Marine Battery Is Bad. There are some sure ways you can tell if your battery is bad by simply taking a good look. If you have a voltmeter built into your sonar and you see a voltage increase after starting the motor the charging system is likely OK.
Ad Our Research Has Helped Over 200 Million People Find the Best Products. Once fully charged marine batteries should be held at a considerably lower voltage to maintain their charge - typically 132 to 134 volts. Add distilled water if necessary.
NEVER allow the stator to charge a battery.
It is more straightforward than the static you would carry this out to know if your battery needs a replacement or not. If you have a 500CCA battery the load should test at 250 amps to indicate voltage with load. The battery will need charged. 2 Using a voltmeter measure the battery voltage and note that reading.
