LEAB Battery Chargers

Low volume, low weight and efficient
Small dimensions and low weight characterizes the LEAB chargers. It has been achieved by the use of switch-mode techniques that make it possible to use small transformers with low losses. An efficient electronic design of charging controls, together with the low heat emission has resulted in an efficiency of better than 100%. The same efficiency is achieved over the full specified input voltage range. The LEAB chargers also have a very low ripple (AC component in DC current).

This causes lower heat build-up in the batteries and thus charging that will spare the batteries and give a longer life. This is especially important for sealed lead-acid batteries with solid electrolyte (Gel-batteries).

Fully charged batteries
In order for the batteries to become fully charged, the output and the charging cycle must be adapted to the battery being charged. Current, voltage and charging times must lie within the specified values of the battery manufacturer and the state of discharge at charging startup must be considered. The temperature of the battery also influences how the battery should be charged. Normally all charging specifications are given at +25°C.

Special consideration must be given to batteries that have been deep discharged. To prevent damage to the battery the charging cycle must start at a lower current that the optimum and then gradually increase to the normal value.

To fully charge a battery requires a flexible battery charger utilizing an advanced control of the charging cycle. The green LED or some other indication that the battery is fully charged is no guarantee that the battery is fully charged. It will only show that the charging cycle of the battery charger has been completed. If the charging cycle is not adapted to the battery it can be far from fully charged.

The LEAB battery chargers have been designed to have the necessary flexibility using an advanced programmable cycle control that makes it possible to get the ideal charging cycle. If the charger is to work at varying temperatures or at a temperature that differs from normal room temperature a temperature measuring device is implemented that automatically compensates the charging voltage.

Input variations
The quality of the power that is fed into a battery charger often has a crucial influence on the output. The variables are voltage, frequency and sinusoidal shape of the current. With a transformer charger the output voltage normally changes in relation to the input voltage. The effectiveness will also decrease dramatically when the input voltage decreases. A certain improvement can be achieved through the use of a design with thyristors but they can only manage a relatively narrow range. Transformers are designed for a certain frequency and for sinusoidal current and deviations from design criterion rapidly causes deterioration in output. Many chargers will not work at all if the input current consists of a square wave.

The LEAB chargers are completely immune to variations in frequency and shape of the input current. They will also give full effect within +/- 10% and correct output values down to –25% of nominal input voltage. Battery charging with power from small gen sets or in areas with weak distribution lines will thus be problem free.

Installation
The LEAB battery chargers are easy to install. The size and weight makes special foundations and fixing hardware redundant. They can be placed on a shelf or on the wall and fixed by appropriate screws. Mains and battery connections can also be adapted to individual wishes. The battery chargers are fitted with standard appliance inlets. The battery cables have connectors, which are compatible with the charger output current.

Dimensions and weight also makes the LEAB charger well suited as on-board chargers. Availability of air for cooling is basically the only concern when placing the chargers.

Safety
LEAB LPC battery chargers will charge your batteries in the safest possible way. Due to control parameters that can be individually adapted to every type and size of battery the charging process is continually controlling the batteries. LEAB has divided the charging curve into 5 charging phases where, for each phase, voltage, current, time and if desired also the temperature are controlled.

When the mains power is connected to the LEAB LPC charger, it will first check if a battery is connected, and, if that is the case, what voltage the battery has. If the voltage is within allowed limits, the charger checks whether the battery is deep discharged or not. When it is, the charging cycle starts with a current adjusted to the state of the battery that will gently bring the battery out of the deep discharged state. If this is not possible the LEAB LPC charger will discontinue the charging and give an error message.

In the other charging phases the battery will be continuously monitored and controlled. When the equalization charging is activated the LEAB LPC charger make sure that the battery cells are equalized and sulphating is counteracted due to all battery cells being charged to the same status.

When the battery is fully charged the charging switches over to maintenance or trickle charging. Self discharge is equalized, and in the event of simultaneous power consumption, this is also replaced to keep the battery full.

With a battery temperature sensor connected voltage will automatically be adjusted to the level specified by the battery manufacturer. Should the temperature raise above the battery’s allowed limit, charging will be interrupted until the temperature has dropped to an acceptable level before charging is resumed. This will prevent destruction of the battery or the possibility of an explosion.

The charging cycle
All LEAB LPC battery charges have a programmable charging characteristic, consisting of 5 different charging phases. They are, Soft start, Constant current, Constant voltage, Equalisation charging and Maintenance or trickle charging. Please note that all charging phases may not be used due to type of battery used or mode of usage for your particular type of requirement.

Economy
Cost of operating the LEAB battery chargers is very favourable, partly due to the high efficiency partly due to the battery saving operation.

As an example a 24 Volt 300 Ah battery will, when empty, take approx 7,6 KWh net from the power source to become fully charged. Some chargers will use as much as 15 KWh from the power source while the LEAB charger will use less than 8,5 KWh. One charging per day in a working year of 220 days means a difference of more than 1400 KWh. This is provided that the chargers manage to charge the battery to 100%. If no, cost to change the batteries prematurely will be added.

When the charger works as a free standing unit it is also interesting to check how much power the charger will consume from the mains when it is not connected to the battery. An onboard charger is not affected since it always will be disconnected from the mains when it is not charging. Other advantages with onboard chargers are that they can be used for topping up the battery charging at shorter intermissions without driving back to where the charger is situated.

The LEAB battery charger will give low operational costs irrespective of where or how they are used.

When the charger works as a free standing unit it is also interesting to check how much power the charger will consume from the mains when it is not connected to the battery. An onboard charger is not affected since it always will be disconnected from the mains when it is not charging. Other advantages with onboard chargers are that they can be used for topping up the battery charging at shorter intermissions without driving back to where the charger is situated.