battery voltage?

Discussion in 'Boat Yard Basics' started by firecat1981, May 15, 2010.

  1. firecat1981

    firecat1981 BBA Counselor

    What is a 12v deep cycle group 29 supposed to read when full?

    I bought a new trickle charger last week and after 3 days on my battery, which was only 30-40% drained, it still wasn't charged up. So I bought a much better speed charge that displays info and has several charge modes. I hook it up and it read around 12 volts, I turn it on charge and within a hour it is above 13 :), and it was on the medium setting. When it hit 14 I started getting nervouse and shut it down, even though it said it was only 76% done with it's cycle.
  2. Brett

    Brett > PRO STAFF <

  3. richg99

    richg99 1652 G3, & 1756 Lowe tinnys


    Battery Charging - Remember you must put back the energy you use immediately. If you don't the battery sulfates and that affects performance and longevity. The alternator is a battery charger. It works well if the battery is not deeply discharged. The alternator tends to overcharge batteries that are very low and the overcharge can damage batteries. In fact an engine starting battery on average has only about 10 deep cycles available when recharged by an alternator. Batteries like to be charged in a certain way, especially when they have been deeply discharged. This type of charging is called 3 step regulated charging. Please note that only special SMART CHARGERS using computer technology can perform 3 step charging techniques. You don't find these types of chargers in parts stores and Wal-Marts. The first step is bulk charging where up to 80% of the battery energy capacity is replaced by the charger at the maximum voltage and current amp rating of the charger. When the battery voltage reaches 14.4 volts this begins the absorption charge step.

    This is where the voltage is held at a constant 14.4 volts and the current (amps) declines until the battery is 98% charged. Next comes the Float Step. This is a regulated voltage of not more than 13.4 volts and usually less than 1 amp of current. This in time will bring the battery to 100% charged or close to it.

    The float charge will not boil or heat batteries but will maintain the batteries at 100% readiness and prevent cycling during long term inactivity. Some Gel Cell and AGM batteries may require special settings or chargers.
  4. firecat1981

    firecat1981 BBA Counselor

    ok my head is spinning. I think the charger I bought is what I need being that its a smart charger and has settings for gel and amg batteries also. I also can choose my charge rate from 2,8, and 12 amps.
    So from what I gather once charged the battery volts will drop and stablize around 12.7 volts.