Sunday 25th Sep 2016 - Logistics Manager

Ramp up the amps

,

The difference between the right forklift truck battery and the wrong one could be more costly than you think, but with so many options to consider where should you begin? Lucy Tesseras takes
a look at the latest developments to keep your operation fully charged.

Choosing the right battery combined with the right charger for any given forklift truck operation is not as simple as it sounds. There are numerous battery and charger options, plus a myriad of other factors to take into account, and when you consider that the battery is one of the most expensive components in a forklift truck, picking the wrong type could be costly.

When looking at the options, John Lawton of EnerSys Motive Power warns companies to beware of the total cost of ownership. “When making a buying decision for batteries the visible costs are those for the battery and charger. What is not always understood at the point of acquisition is the operating and maintenance costs for the life of the product,” he says.

There are three types of lead acid battery technology generally used in materials handling equipment: standard design flooded cells, low maintenance flooded cells and maintenance-free gel or AGM cells, which are most suited to applications with lower depth of discharge.

As flooded batteries need to be topped up with deionised water on a regular basis, Lawton says it is important to factor in the cost of the water and labour time needed to complete the task, which will vary depending on the type of battery used. The amount of logisticsmanager January 2011 Typically, high frequency chargers require five to ten per cent less power per battery
recharge. Bob Hine electricity needed to recharge batteries should also be taken into account, particularly as this will differ from system to system.

As a result, Lawton says: “Specifiers and buyers of batteries need to consider the ‘true life time cost’, in other words, the cost of the battery and charger plus the water, labour and electricity costs to maintain it throughout its operational life.”

EnerSys has launched two new products designed to reduce operating costs, the Hawker Water Less and Hawker XFC Flex.

 Hawker Water Less is based on the company’s PzS technology flooded batteries, but offers increased topping-up intervals of up to four weeks when used with 50Hz charging technology and eight weeks with Hawker HF chargers. Lawton reckons this can be extended to 13 or even 20 weeks with the optional extra of electrolyte circulation and a specific charging profile.

Labour savings of between 60-90 per cent can be created thanks to less frequent topping up and electricity costs can be reduced by up to 25 per cent.

The Hawker XFC Flex uses thin plate pure lead technology and is totally maintenance-free meaning water topping-up is not needed. Batteries can be discharged as required and be safely opportunity charged during breaks, shift change-overs and whenever the truck is idle. The battery can also be safely operated in a partially charged state.

Opportunity charging was the key design goal for Bendi when it began developing its new charging system. Simon Brown, managing director of Translift Bendi, says: “Batteries are one of the largest component costs in an electric forklift. Ideally, operators need to be able to recharge their trucks during breaks and lunch time… [but] unfortunately charging batteries for short amounts of time can reduce the life of the battery, reduce its storage capacity and cause overheating. “There have been many attempts to overcome this issue but the majority of those new battery concepts only really last for up to five years – the industry standard warranty for batteries.”

Bendi’s new system looks to overcome these problems as it will allow “sporadic use of trucks over a 24-hour period with opportunity charging and without battery changing,” says Brown. “It’s a very simple idea with an innovative application of some simple electronic additions that will transform the modus operandi which the rest of the industry has fallen in to conforming with.”

The new system is currently being tested. Bendi hopes to release it as soon as this is complete in mid-summer 2011.

Despite having been around for more than two decades, BITA reckons high frequency chargers have evolved considerably in recent years.

“Higher efficiency is their principal benefit,” says Bob Hine of BITA, “due to the fact they can use smaller, more efficient components with lower losses. While precise figures vary between models, typically high frequency chargers require five to ten per cent less power per battery recharge. In turn, AC input currents are approximately 30 per cent lower than those drawn by traditional regulated chargers.”

As such, the lower running cost means that high frequency chargers “can usually repay their slightly higher initial acquisition costs over a five-year lift truck operating lifecycle,” he adds.

Peter Atack, product & technical manager at GNB Industrial Power, formerly known as Exide Technologies, confirms that “selecting a battery is not always straight-forward as there is a bewildering choice”.

He is also keen to point out that “unfortunately, not all batteries are created equal. Tests have shown that the actual performance from some overseas suppliers do not actually live up to their quoted rating.” To help weigh up the options, GNB is able to provide customers with cost-predictions based on different working arrangements before advising which option is most suitable. He adds that as GNB manufactures both batteries and chargers, products can be “matched” to ensure the optimal charging profile.

Incorrect battery charging and use are the two main causes of a short service life for traction batteries. To combat this, GNB has developed the 2100HP and 2100SP chargers which can protect the battery from being opportunity charged too often.

Peter Atack says: “It can automatically detect the state of charge of the battery on connection and will perform a full recharge only when it is satisfied that the battery requires it.”

Optimal
However, he suggests that battery management systems are the best way of ensuring optimal usage and recharging. GNB’s 2100.net is a computerised system that allows users of electric vehicles to manage batteries so they are recharged at the correct time and for the appropriate duration. “This ensures optimal use of batteries, thereby extending their efficiency and life – a
tangible benefit for modern businesses with 24-hour operation,” he says.

“Each charger is linked to a central PC that can monitor up to 255 batteries and provide real-time status reports. Charging points can be categorised by truck type or warehouse area, or any other user-defined category. The system automatically prioritises the next battery to use and alarms are triggered if an incorrect battery is removed. Security is ensured by a volt-free fire alarm interlock and automatic shutdown in the event of ventilation failure. Additionally, ‘safety disconnect’ ensures that no power will flow if the ‘wrong’ battery is disconnected.”

Charging rates can also be automatically adjusted within defined power limitations by controlling the number of batteries that can be activated at any one time, plus it can provide management reports to show battery status, cycles charged, or highlight any faults. Roger Massey of Barloworld Handling agrees that: “Effective battery management helps companies maintain performance with extended battery shift life, reduced utility costs and less downtime.”

Barloworld’s Total Battery Management package is designed to deliver optimised battery performance for the contract life. It uses energy efficient high frequency chargers and low maintenance batteries which feature an air circulation system for quicker charging with up to 75 per cent reduction in emissions produced by charging.

As part of the programme, Barloworld carries out a site survey to determine the correct truck and battery specification and puts in place a planned maintenance schedule for the batteries with its engineers.

Massey adds: “Total battery management increases truck availability, reduces utility costs and the costs of battery replacement or damage caused by improper use or poor maintenance.”

To prolong battery life, Jungheinrich UK’s Craig Johnson says it is essential to keep electrolyte levels high. “Jungheinrich’s electric-powered trucks are supplied as standard with a battery discharge indicator unit that automatically stops the mast from lifting and allows the truck to travel as soon as the truck’s battery is approaching 80 per cent discharged. A battery is prone
to lasting damage once it is over 80 per cent discharged,” he warns.

While cost and power are important, safety should also be a key consideration for any organisation operating forklift trucks. However, when it comes to safety often the focus is on reducing speed, lowering fork height and removing hazards in the warehouse, but batteries should not be overlooked.

The Fork Lift Truck Association suggests that the key to successful battery management lies in a combination of increased risk awareness and safe handling practices. Failure to do so could lead to serious injury and could be fatal in severe cases.

The FLTA has outlined a number of preventative measures that should be adhered to when using electric forklifts. Firstly, a good ventilation system is essential as lead acid batteries produce hydrogen and oxygen, which can become explosive at four per cent concentration. A good ventilation system will ensure the hydrogen concentration is kept within a safe one per cent.

As there is a risk of explosion, any ignition sources, such as areas where welding or grinding take place, should be kept at a safe distance, particularly during charging. Areas used for battery storage and maintenance should also be carefully considered.

Another danger of working with electric forklift truck batteries is the risk of shocks and burns caused by sparks and shorts. The FLTA says that while most people are aware of the risks associated with AC mains electricity, the properties of the DC current of a battery should never be underestimated as simply touching a conductive object such as a tool to two cell terminals
simultaneously can cause instant death.

The risk can be minimised by insulating all tools and lifting equipment, removing all jewellery and watches before working with batteries, emptying pockets of metallic items, inspecting cables and connectors regularly and wearing protective clothing such as goggles and gloves. Only trained and authorised personnel should ever be allowed to work with chargers.

Danger
The lead acid in batteries also poses burn and irritation dangers due to chemical electrolyte. To minimise the risk of spills, the FLTA advises that batteries should be kept upright and never overfilled. If any spills do occur clothing should be thoroughly washed with water, and if any gets into eyes they should be immediately flooded with fresh water and medical attention should be
sought urgently.

Any spillages on the floor or on structures should be neutralised using an alkaline substance like soda ash. It may seem obvious, but manual handling should also be carried out safely, particularly when changing batteries, because they can be extremely heavy and mistreatment could lead to back injury or trapped fingers.

John Lawton of EnerSys says: “Forklift batteries are heavy – sometimes more than 1,000 kilos. Employers should familiarise themselves with the manual handling regulations that apply in their country and provide mechanical assistance to their employees if battery changing is to be done.

“The current UK recommended maximum weight that should be manually handled is 25 kilos – this refers to lifting, pushing and pulling an object.” EnerSys offers a range of battery change equipment to avoid the risks of heavy manual handling tasks.

innovation
Fully Charged

Schlatbau, the supplier of components for forklift trucks, has unveiled the LV500 charging connecter which is designed to support high ampacity for rapid charging with nominal loads of up to 500 amps. It is the latest product in the LV series which already includes 80, 160 and 320 amp connectors.

The LV500 system claims to provide long-term reliability and operating safety, while delivering maximum performance in harsh conditions. It has a form-stable, glass fibre reinforced shell and the connector is resistant to mechanical stress, shock and vibration, acids and extreme temperatures.

Machine-turned contacts offer an increased contact area, enabling higher amperage, reduced temperature rise and low contact resistance during continued operation. Schaltbau says this results in high contact forces that do not deteriorate over time and less wear and tear during the mating cycle.

case study
GM powers up Astra production

General Motors has saved energy, improved productivity and optimised line side delivery operations at its Astra car plant in Ellesmere Port by switching to electric tow tractors from gas-powered units.

The plant manufactures Astra cars and vans and employs more than 2,000 people. The operation incorporates a number of processes that require JIT delivery of components and assemblies direct to the line side. A major drawback of using LPG-powered tractors was that they had to unhitch from the trolleys and leave the production building to visit outdoor gas bottle stores whenever they needed refuelling. This generally occurred once every shift which was time consuming and could disrupt the operation.

The site identified a number of benefits it could achieve by switching to electric-powered tractors operating continuously throughout the shift. It decided on a combination of 25 Linde P602 tow tractors and Hawker batteries from EnerSys with Hawker LifeSpeed high speed chargers.

The system allows trucks to be topup charged for short periods during scheduled work breaks to maintain enough power to operate throughout the shift. This is supplemented by overnight charging at the weekend.

This saves around ten minutes per truck per day, which works out as 250 working minutes saved per shift.

Additionally, maintenance and cleaning have been reduced, and as doors don’t have to be opened so often, it has cut the energy required to produce each Astra by 50 per cent.

case study
99p Stores saves thousands

Budget retailer 99p Stores is on target to save more than a quarter of a million pounds over five years after enlisting Hoppecke to help minimise material handling costs at its new warehouse and distribution centre in Northampton.

The company was keen to choose the right batteries and charging system to get the most out of its fleet of 42 Linde low-level order pickers and 14 articulated trucks.

Previously, batteries were charged inefficiently during eight hour shifts, which lead to excessive downtime and wear on batteries, plus charger plugs were getting damaged because of their location.

To help avoid accidental damage, Hoppecke installed its trakAir high frequency charger system clear of the floor. The system is capable of charging 32 batteries at any one time and incorporates a “call forward”

function that signals to operators which battery should be used next. It also features a downloadable information system that allows managers to monitor performance and identify any problems.

Hussein Lalani, operations director at 99p Stores, adds: “The complete system was only installed in May 2010 but we are already on target to save around £50,000 this year. Over the length of the contract we expect to save around £250,000 in electricity costs alone. On top of this, further savings will be made through reduced wear and tear on our trucks, reductions in downtime and the fact we will no longer need to bring in extra trucks to cope with peaks in demand.”