01/20111/4
PRESS RELEASE
Fronius presents ground-breaking charging technology for longer battery service life
New charging process gives the “coolest” battery charge
(Wels, Austria, February 19th 2013) Fronius, the Austrian battery charging systems specialist, used the LogiMAT trade fair to show off a new generation of battery chargers that turn hopes into reality. As well as delivering high energy efficiency, the service life of traction batteries for electric forklift trucks has been extended dramatically. The newly developed Ri charging process means charging is now possible with the barest minimum of heat generation.
“The cost-effectiveness of a forklift truck is largely down to the traction battery and its durability,” explains a guideline of the ZVEI (German Electrical and Electronic Manufacturers' Association) based in Frankfurt am Main. It continues: “One of the key factors affecting service life is the charging technology. It is a well-known fact that more batteries are damaged through incorrect charging than through discharging.” With its new generation of “Selectiva” battery chargers for traction batteries, Fronius, the Austrian battery charging systems specialist, is the first company to meet this challenge head-on.
Higher temperatures - especially when in excess of 40°C - have a particularly negative effect on the service life of a lead-acid battery, as they accelerate the chemical reactions. Excessive overcharging speeds up battery contamination (and thus accelerates the self discharge rate) and the increased gassing leads to more water consumption and a faster build-up of hazardous oxyhydrogen. Ultimately, the user is forced to invest several thousand euros (GB: pounds) in a new battery far sooner than should be necessary. These negative factors are kept at bay by the latest generation of Selectiva devices with the Ri charging process from Fronius. Equipped with three-phase connections, the new units are primarily designed for 24 V, 48 V and 80 V traction batteries.
Charge losses are a major cause of battery warming. They are most commonly found with the old 50 Hz transformer technology, but their presence is still felt to a certain extent during the main charge phase of conventional high frequency (inverter) technology and the earlier Fronius “Active Inverter Technology”. Old transformer technology and conventional inverter technology also warm the battery through overcharging during the recharging phase, as the battery state is completely ignored. Only the earlier Fronius chargers take the charge level of the battery into account during the recharging phase to ensure that any overcharging of the battery is kept to an absolute minimum.
Unique charging cycles per battery - every time
The reasons for these charge losses are the predefined charging characteristics that charge the battery with a preset, and sometimes too high, charging current “I” - regardless of the battery acid concentration and therefore the state of charge. Fronius has recognised the fallacy of this approach and has now developed the Ri charging process with an individual characteristic. “Ri” stands for the effective inner resistance of the battery: a battery-specific value that changes during charging and discharging due to the fluctuating acid concentrations and parasitic effects, e.g. diffusion processes, polarisation-overvoltage or the conversion of lead sulphate into lead oxide.The key to the new Ri characteristic is that the charging voltage is determined by measuring the effective inner resistance. This ensures that the charging current is automatically adjusted to remain in line with the effective inner resistance curve of the battery. In other words, if the effective inner resistance rises (battery has a lower charging capability) in relation to when charging began, the charging current is reduced and charge losses are avoided. If the effective inner resistance drops during charging (charging capability increases), then the charging current is raised automatically so that it can be reduced later on in the charging process - once more as determined by an increasing effective inner resistance (battery full, therefore charging capability drops). This means that every charging cycle for every battery is a unique entity with an individual characteristic.
To enable the charger to specify the starting value and the ongoing progression of the charging voltage, the current battery state of charge is constantly recorded. This means that the type of battery in question, how old it is, its temperature and discharge level are all monitored. Using this information, the charger software then modifies the individual charging phases by keeping the voltage curve constant and regulating the charging current in line with the effective inner resistance curve. The Ri charging process from Fronius is therefore essentially a closed-loop process.
Previously unattainable: overall efficiency of 84%
In simple terms, this revolutionary method achieves a level of charging efficiency previously thought impossible: whereas 50 Hz transformer technology achieves an average of 70% efficiency, conventional inverter technology reaches 75% and the earlier Fronius “Active Inverter Technology” generates 80%, the Ri charging process is capable of an impressive 90%. Together with the 93% efficiency offered by the new generation of “Selectiva” devices, the Austrian experts have achieved an overall battery charging efficiency of no less than 84%.
An additional major benefit of this refined Fronius battery charger is that only the battery voltage and charging time have to be set. In reality, many batteries that are connected to the charger are only partly discharged. By setting a charging time, such as seven hours, the charging process can be “stretched out” over this period. Adopting this approach enables the battery to be charged extremely gently due to the lower energy input and the correspondingly lower warming effect. For companies with fluctuating forklift truck utilisation levels, harmful overcharging is prevented and batteries remain undamaged. Furthermore, peak currents are prevented in situations where the charging of multiple forklift truck batteries starts simultaneously at the end of a shift. As only the battery voltage and available charging time have to be set on the new battery chargers, the battery capacity does not have to be known. Consequently a single charger can be used to charge several batteries of different capacities - absolutely no setup work between each one is required.
And, even after all this, Fronius is still not finished with the service life-extending features: a light blue LED on the new Selectiva charger only lights up once the battery has cooled down after charging. Optional counters show which of the charged batteries in a larger battery charging facility has cooled the most and should be the first one to use in an electric stacker, narrow-aisle stacker or electro-tractor.
Achieving the maximum battery service life is only one of the many criteria that make the new generation of Ri characteristic devices from Fronius so attractive. A plethora of improvements over its predecessors provide the new generation with maximum energy efficiency, unbeatable safety, more user-friendliness and an improved service package.
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For more information, see:
Ri charging process:
ZVEI – Zentralverband Elektrotechnik- und Elektronikindustrie e.V. [German Electrical and Electronic Manufacturers' Association] (Industrial batteries – data sheet no. 8):
/ Picture 1The new generation of “Selectiva” battery charging systems with the innovative Ri characteristic sets new standards. As well as delivering high energy efficiency, the service life of traction batteries for electric forklift trucks has been extended dramatically. (Photo: Fronius)
Image file: Fronius_Selectiva_Ri_BatteryServiceLife_01.jpg
/ Picture 2
Prolongs service life: the light blue LED on the new Selectiva charger lights up as soon as the battery has cooled after charging. The forklift driver is left in no doubt as to which is the best battery to use. (Photo: Fronius)
Image file: Fronius_Selectiva_Ri_BatteryServiceLife_02.jpg
/ Picture 3
The “coolest” charge: unlike other battery charging technologies, the Ri charging process keeps harmful warming during charging as low as possible. (Graphic: Fronius)
Image file: Fronius_Selectiva_Ri_BatteryServiceLife_03.jpg
/ Picture 4
Chargers employing the old 50 Hz transformer technology significantly warm the battery during the main charging and recharging phases, which considerably shortens the battery service life.
(Graphic: Fronius)
Image file: Fronius_Selectiva_Ri_BatteryServiceLife_04.jpg
/ Picture 5
The high frequency (inverter) technology warms the battery a little during the main charging phase. However, the battery is heavily overcharged and warmed during the recharging phase.
(Graphic: Fronius)
Image file: Fronius_Selectiva_Ri_BatteryServiceLife_05.jpg
Copyright to photos: Fronius International GmbH, reproduction free of charge
Fronius International GmbH
Fronius International is an Austrian company with headquarters in Pettenbach and other sites in Wels, Thalheim, Steinhaus and Sattledt. With over 3,257 employees worldwide, the company is active in the fields of battery charging systems, welding technology and solar electronics. Around 94% of its products are exported through 19 international Fronius subsidiaries and sales partners/representatives in over 60 countries. With its outstanding products and services and 878 active patents, Fronius is world technology leader.
Fronius International GmbH
Enquiries: Boris Ringwald, +43 664 602416436,
Copies: Boris Ringwald, Froniusplatz 1, 4600 Wels, Austria
Fronius U.K. Limited
Enquiries: Ross Adams, +44 7580 076988,
Copies: Ross Adams, Maidstone Road, Kingston, Milton Keynes, MK10 0BD United Kingdom
01/20111/4