AC to DC battery chargers

The PMP range of high frequency battery chargers represent 20 years of experience in the field of AC to DC High frequency battery charger technologies. The battery charger range is designed for a wide range of input voltage 100V to 230V AC. All output voltages is designed for optimum battery charging. The KOP series battery charger allow for 5 level pre-program ability which allow specific battery charging patterns for any kind of battery.

All the battery chargers offer, boost float and trickle charge facility (Three stage battery charging).

Please refer to our explanation on how to best charge batteries !!!

HOW to CHARGE  with a battery charger

Basics

• Coulumetric Efficiency
• Minimum voltage
• Cyclic versus Standby charging
• Temperature compensation

Overnight Charging

• Unregulated Transformer-based Chargers
• Taper Charging
• Constant Voltage Charging
• Constant Current Charging

Fast Charging

• Fast Charging Options
• Three step chargers

Coulometric efficiency
The coulometric charging efficiency of sealed lead acid batteries is typically 70%, meaning that you must put 142 amp hours into the battery for every 100 amp hours you get out. This varies somewhat depending on the temperature, speed of charge, and battery type.

Minimum battery charging voltage
Anything above 2.15 volts per cell will charge a lead acid battery, this is the voltage of the basic chemistry. However, most of the time a higher voltage is used because it forces the charging reaction at a higher rate. The voltage to avoid is the gassing voltage, which limits how high the voltage can go before undesirable chemical reactions take place.

The basic lead acid battery is ancient and a lot of different battery charge methods have been used. The lead acid chemistry is fairly tolerant of overcharging, which allows marketing organizations to get to extremely cheap battery chargers. We offer a range of battery chargers from inexpensive to very sophisticated, depending on the requirements of the customer.

Cyclic battery charging  versus Standby battery charging.
Some lead acid batteries are used in a standby condition in which they are rarely cycled, but kept constantly on charge. These batteries can be very long lived if they are charged at a float voltage of 2.25 to 2.3 volts/cell (at 25 degrees C). This low voltage is to prevent the battery from losing water during long float charging. Those batteries that are used in deep discharge cycling mode can be charged up to 2.45 volts/cell to get the highest capacity.

Temperature compensation

Voltage table for cyclic use charging

Voltage table for standby use charging

Unregulated Transformer-Based Chargers
These are the absolute cheapest battery chargers around. They consist of a wall mount transformer and a diode. The transformer is designed to deliver 13 to 14 volts over a reasonable current range. The biggest problem with this approach is that when the current tapers off, the voltage raises to 15, 16, 17, even 18 volts. At these high voltages electrolysis of the water in the battery starts in. These must not be left to trickle or float charge a battery, they must be disconnected when the battery is fully charged.

The transformer is so designed as to limit the current while the battery is in absorption mode. As the battery voltage rises the current decreases to top off the battery. Because the transformer is used to control the current and voltage these chargers are typically heavy and get hot. For best results the battery should be disconnected from the battery charger within 12-24 hours.

Taper chargers
Another cheap way to charge a sealed lead acid battery battery is called a taper charge. Either constant voltage battery charger or constant current battery charger is applied to the battery through a combination of transformer, diode, and resistance. The unregulated chargers mentioned above are taper chargers. A better, and not very expensive, alternative is a regulated taper battery charger. These don't let the voltage climb higher than the trickle charge voltage, so they can be also be used to maintain a battery. They won't damage the battery if left on charge too long, and they don't change their charging characteristics if the line voltage should change.

There are two ways to make a regulated charger. The first is to use a transformer and a simple voltage regulation circuit. This has the disadvantages of weight and heat, but it is still inexpensive. The second uses a modern switching power supply in a wall mount or desk mount package. These low power high frequency battery chargers  are surprisingly cheap, efficient, and small. They are rapidly taking over the overnight charging requirement in consumer equipment.

Constant current battery chargers
A more sophisticated and not much more expensive battery charger uses an electric circuit to control the charging current. This method is useful for recovering batteries that have suffered from extensive storage without charging, but is capable of overcharging a battery if there is not some voltage limiting function, usually from the transformer. For this reason these chargers are limited to slow charging.

Constant Voltage battery Chargers (Taper plus current limit)
A circuit that is set for the maximum allowable charge voltage, but has a current limit to control the initial absorption current can produce a very nice charger. This type of battery charger can both charge at a reasonable rate and maintain the battery at full charge without damage. Not all constant voltage chargers are made equal, however, because the maximum voltage is a function of temperature. A temperature compensated charger is a little more expensive, and should be used where the temperature varies significantly from room temperature.

Fast chargers are higher power units, designed to charge in less than 4 hours. These battery chargers require active charge termination and often have advanced features such as battery test, bad battery recovery, and automatic maintenance.

Typical Charging curves for  quick chargers:
This charger starts at 8 amps and maintains a near-constant current until nearly full.

This is the fundamental algorithm of the power master quick chargers for lead acid batteries. The curve shown is for a 24 volt (12 cell) battery charger, but the curve is similar at other voltages. The timing depends on the size of the battery you are using. At point #1 the battery is tested. If the battery is bad a rejuvenation algorithm is started. If the battery is good the charger goes into constant current mode until the voltage reaches 2.3 volts/cell. Then at point #2 the charger goes into constant voltage mode until the current drops to about 10% of the initial value, indicating a nominally full charge. Then at point #3 the charger goes into float charging mode at about 2.3 volts /cell to complete the fill and to maintain the battery. At this voltage the battery is safe from overcharge.

High frequency battery charger

The range of high frequency battery chargers represent 20 years of experience in the field of battery charger technologies. The battery charger range is designed for a wide range of input voltage 100V to 230V AC. All output voltages is designed for optimum battery charging. The KOP series battery charger  allow for 5 level preprogram ability which allow specific  battery charging patterns for any kind of battery.

All the battery chargers offer, boost float and trickle charge facility.

Main Features in the page:

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EXCISTM

Maintenance Free
Factory Sealed - Never Add Water Now Manufactured in South Africa Product and Service Benefits Now manufactured in South Africa by First National Battery. Countrywide network of branches and agencies.
A comprehensive product warranty.

Salient Design Features

Technical Details

EASY TO MAINTAIN
LONG FLOAT LIFE: Calcium alloy grids and plates to minimise corrosion.
Envelope separators to eliminate internal short circuits.
HIGH CYCLING DESIGN: High density active material formulation.
EXCEPTIONAL HIGH
RATE PERFORMANCE:
ENHANCED SAFETY:
EASY TO CONNECT:
Built in State of Charge Indicator.
Available with stud or taper terminals.
12 Volt 102 Ah (C20, 25°C) Dry Weight : 19kg, Wet Weight: 26.5 kg
Glass matt backed separators for active material retention.
Oversized internal inter-cell connector cross section.
Central venting system.
Flashback arrestor.
High impact strength container.
: For more information contact
FIRST NATIONAL BATTERY INDUSTRIAL
CALL TOLL FREE
0800 112600