Maximum safety while charging batteries
Charging starter batteries for cars, or traction batteries for forklift trucks or cleaning machines is not without its risks. They are usually charged with low DC voltages and high currents. High charging currents, the potential release of explosive gases during battery charging, the handling of chemicals (if necessary), for example electrolytes in the energy storage device, and unsupervised operation when the employee has finished work all present various hazards. However, these risks are significantly reduced with the use of the correct chargers and adherence to important regulations.
Fronius, the Austrian know-how leader in charging traction batteries for electrically powered forklift trucks, has been a developer and supplier of battery charging systems with the highest safety standards for many years. The Selectiva range boasts four power categories and housing variants to provide a complete product portfolio for 2 to 80 V traction batteries. Fronius battery charging systems guarantee maximum efficiency in terms of energy costs and battery life. 100% safety during charging of the battery, ease of use and flexible installation options ensure trouble-free charging processes. All systems are equipped with a voltage-free charging plug and de-energised leads as standard for a spark-free connection. Mains voltage monitoring switches the battery charging system off if the tolerance limits are exceeded. If the temperature of the charger is too high, for example due to high ambient temperatures or insufficient cooling, the thermal overload protection prevents damage to the battery charging system. The safety cut-out detects incorrect charging processes, for example if the charging time predicted by the battery charging system is exceeded or due to faulty battery cells. The Fronius devices are electronic and minimise the risk of oxyhydrogen explosions.
The underestimated danger: oxyhydrogen
The danger presented by oxyhydrogen is occasionally underestimated. During charging, in particular overcharging, hydrogen and other gases can build up inside the battery and be released into the surrounding air. This results in highly explosive oxyhydrogen, a mixture of hydrogen and oxygen in the surrounding air. In certain concentrations, all it takes is a spark to cause an explosion. The innovative Ri charging process for the “Selectiva” range of battery charging systems, successfully launched in 2013, leads to reduced gas formation during charging and thus a reduced risk of oxyhydrogen and odour build-up. The charge level of the battery is taken into account during the entire Ri charging process, minimising overcharging of the battery. An additional advantage of the Ri charging process is that it automatically detects the voltage and capacity of the battery. This prevents any faults occurring as a result of incorrect inputs, making the system even safer.
The “external start/stop” option prevents sparking if the charging plug is disconnected prematurely during the charging process. A pilot contact in the plug terminates the charging process in a controlled manner, eliminating the danger of an oxyhydrogen explosion.
Fronius engineers also turned their attention to various other safety improvements. Additional functions, such as the adjustable start of charging, further reduce peak loads. Even so-called “Monday morning syndrome” can be avoided using a programmable, time-controlled equalising charge that ensures the battery is fully-charged over the weekend and after Bank Holidays. Faults, warnings or even information can be indicated during the charging process by illuminated LED strips or flashing LED indicators. To improve safety, explanatory texts and a service call-out telephone number appear whenever the charger displays an error message.
Yet another safety feature is the optional USB interface, which, in addition to data backup, enables a system update and various analyses of the charging process to be carried out. And it doesn’t end there – reverse polarity protection that prevents incorrect polarity due to the reversal of the plus and minus poles, an intelligent ventilation system that prevents contamination and thus short-circuiting of the battery charging system due to dust particles and a delayed charge end complete the safety functions for the Fronius battery charging systems.
Maximum safety through complete charging systems
For those who want an absolute guarantee that their charging stations or charging systems comply with all the relevant regulations, Fronius offers complete solutions for the charging of traction batteries for forklift trucks; from analysis, planning and installation to system operation. Fronius supplies battery charging systems that are compliant with standards, have various modules and are available in different designs as required. The modules – fitted with mandatory warning notices – can accommodate one or more battery charging systems. Where space permits, both sides of the modules can be used, saving space. When planning battery charging rooms and installing the systems, Fronius always ensures that the safety clearances to flammable objects, and particularly to hazardous areas with a fire or explosion risk, are observed and that the correct markings are applied to the floor and to the wall. The specially developed safety module comprises a first-aid box, a fire extinguisher, an eyewash kit and a printed copy of the safety rules. The safety module can be tailored to satisfy the regulations laid down by individual companies.