Pontoon Boat & Deck Boat Forum

I am having a problem with my batteries not charging. I charged them the beginning of the season in early May. I have one new battery and one older battery connected through a 1/2/All/Off switch. I have an older Johnson 115hp outboard. I noticed my voltmeter going down slowly over the last two months. I am not running anything big. I have a stereo with two 6x9's and no amps. I am going to charge the batteries up today and see what happens. I am thinking one of the batteries might be bad, the generator on the motor is not running right, or something else. Any ideas what I should be looking for? Thanks for the help.

Measure the voltage on the battery post them selves not at the connection points then start the motor and run the fast idle up to 2500 or so rpms , then retest the voltage, it should be higher with the motor running, if its the same then you have a charging problem.