A-C Series - These chargers are new "switching" type devices which operate without the use of transformers. I.C.'s control and regulate current and voltage and automatically switch from the higher fast charge voltage to the lower float charge voltage when batteries are very close to being fully charged.
At the float voltage, it is safe to leave the battery connected to the charger indefinitely, making them ideal for cyclic applications where recharge time is critical and timely charge termination cannot be counted on. These chargers ensure optimum battery performance & service life.
Notes - Recharge time depends on the depth of the preceding discharge and the output current of the charger. To determine the approximate recharge time of a fully discharged battery, divide the batteries capacity stated in amp hours by the rated output current of the charger (amps) and multiply the resulting number of hours by a factor of 1.75 to compensate for the declining output current during the charge cycle. If the amount of amp hours discharged from the battery is known, use it instead of the batteries capacity to make the calculation.
When charging batteries in series - This is when the positive terminal of one battery is connected to the negative terminal of the other. All batteries in the string will receive the same amount of charge current, individual battery voltages may vary.
When charging batteries in parallel - This is when the positive terminals are connected with positive terminals and negative terminals are connected with negative terminals. All batteries in the string are subject to the same charge voltage, but the charge current each battery receives can and will vary until equalization is reached.