Miles Cook
April 24, 2006

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The Schumacher SE-82-6 is an excellent general-purpose battery charger available for a reasonable price. It and others can be found in most auto-parts stores for less than $30. Although not as suited to low-amperage charging for stored batteries as one like the CTEK charger, this charger has a healthy 6-amp charge-current rating to get discharged batteries back into shape in a matter of hours. Schumacher also has a full line of battery chargers for a variety of applications available at most auto-parts retailers.
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Another handy feature of this Schumacher charger is its ability to charge 6-volt batteries, which are often found in older cars such as a Ford Model A, and boats such as classic wooden speedboats from the '30s, '40s, and '50s.

The absorption mode applies a peak charge of 14.4-14.7 volts until the battery is fully charged. The charge current then tapers, and voltage is kept constant at a set level. The final pulse mode sends out current pulses, and charging ranges from 95 to 100 percent. The battery receives a pulse if its voltage falls. This stage keeps a battery in good condition although it's not being used on a regular basis. The compact CTEK charger is fully sealed and weighs just over one pound.

National Parts Depot also offers the Deltran Battery Tender, primarily a maintenance-type charger. Its 1.25-amp constant-current reaches and maintains a full charge indefinitely by automatically switching to a storage charge. It won't overheat or overcharge a battery and it adjusts for temperature. In addition, the

Battery Tender has microchip circuitry that avoids shorting or sparking if the clips inadvertently touch each other. For example, if storing a car for the winter, NPD suggests removing the battery from the car and leaving the Battery Tender connected while the battery isn't in use. NPD also has a Battery Tender Jr., a more compact unit with a 750-milliamp current rating. It will also charge and maintain a battery.

A general-purpose charger, the sort sold at any auto parts store, is also worth considering and is usually available at a budget price. A good example is the Schumacher SE-82-6 dual-rate charger that we purchased at a local Southern California Kragen Auto Parts store for 25 bucks. The difference between a typical charger such as the Schumacher and the others mentioned is its higher amperage output. At its 6-amp charge rate, it'll charge a battery in about 6-8 hours. And while its 2-amp slow-rate setting is good for smaller batteries, this is a manual charger that will continue to charge even after the battery is fully charged. A visual check of the ammeter is required to know when the battery is fully charged. This unit is not as suitable for long-term low-amperage trickle charging on a stored battery.