Batteries - many shapes and sizes

10th of June 2019
Batteries - many shapes and sizes

Batteries come in all shapes and sizes. But how far does the environment in which cleaning takes place influence the type of battery you choose to power your machine, asks Ann Laffeaty?

Battery-powered cleaning machines offer a number of benefits for the end user. They remove the need for the operator to rely on an external power source, and they eliminate the tripping hazard of an electrical cable.

Flooded, AGM and gel batteries have long been used in cleaning machines but the industry is developing all the time. Lithium ion batteries are becoming increasingly popular while new technologies using sodium ion, magnesium ion and lithium air are also coming on stream.

So, how do cleaning companies choose between this large assortment of batteries when powering their machines? And how far does the environment in which cleaning take place dictate the type of battery required?

Customers who need an ergonomic, lightweight machine usually opt for a smaller battery says Kärcher floorcare product manager Cassio Murillo. “They also choose a small battery if they want a hand-held window vacuum or a compact machine that is easy to transport and store,” he said.

On the other hand, larger batteries offer a greater energy capacity in environments where autonomy is the main focus, he says. “For example, a big ride-on scrubber dryer in a large warehouse needs to be able to clean a sizeable area with one fully charged battery, and factors such as weight would not be so relevant here.”

Time is a valuable commodity - and a powerful battery can generate savings of up to 25 per cent, he claims. “Since studies indicate the cost of labour can be as much as 85 per cent of the total cleaning bill, the potential for savings is clear,” he said.

According to Murillo, larger batteries are used in environments where productivity is key. “You need to weigh up the time spent actually working with the machine against the time it takes to charge or change the battery, since the machine cannot be used while the battery is charging,” he said.

Flooded batteries – generally among the lowest-cost options available - are mainly used in more price-sensitive sectors, he says. “Flooded batteries tend to be the most economically viable option in capacity areas beyond 240/300 Ampere hours, but you need to remember to keep the fluid levels refilled,” he said.

Traditional batteries remain popular in the cleaning industry due to their lower price compared with Li-ion products, says Murillo.  “However, the benefits of Li-Ion mean they’re becoming more popular every year and the challenge is to make them affordable so that they can replace bigger batteries in big machines,” he said.

He says Li-ion batteries perform better than traditional ones in harsh environments while still delivering high energy. Lead acid batteries can lose up to 70 per cent of their capacity.

“The ability to use a battery at low temperatures does not automatically permit charging under these conditions, because charging is more delicate than discharging,” he points out. “Bitterly cold conditions can make charging more difficult – particularly with Li-ion. And careless charging at low temperatures can inflict permanent damage to the battery.”

Kärcher offers a range of battery-powered machines including vacuum cleaners, sweepers and scrubber-dryers powered by Li-Ion.

TPPL product manager EMEA at EnerSys Martin Walsh says larger batteries are required for cleaning in large areas where greater autonomy is needed. “Ride-on machines are generally powered by bigger blocks or even 2V cells,” he said. “Bigger machines are sold based on the square meterage of the area.

“In challenging environments there is a need for a robust motive power solution that can overcome misuse and that requires little maintenance – such as no water to be topped up. On the other hand, small walk-behind machines require small batteries with a high volumetric and gravimetric energy density, such as those in our NexSys TPPL range.”

NexSys 2V batteries are based on Thin Plate Pure Lead (TPPL) technology and are said to be non-spillable while producing low gas emissions.

Safety is always a concern for EnerSys, according to Walsh. “All batteries emit hydrogen during recharge, so using products with low emissions enhances safety,” he said.

Many considerations

A customer’s battery choice needs to take in a number of considerations, says Battery Supplies general manager Alexander De Soete. “Each type of technology offers its own advantages and customers will weigh up the benefits along with the price and the environment in which cleaning will take place,” he said.

Most cleaning machines today are equipped with lead batteries, he claims. “For price reasons customers may opt for a PZS flooded monoblock or a US Deepcycle battery,” he said. “These offer a long life if they are treated correctly and if good maintenance is ensured.

“Alternatively, gel batteries offer fewer cycles than open battery technologies but have the benefit of being completely maintenance-free.”

Battery Supplies offers a new range of lead carbon batteries said to combine the benefits of a long life with maintenance-free energy.

Heavy lead options tend to be preferred in situations where operating times are fixed and where batteries are discharged deeply during each shift, he said.

“Since the battery will be used in the same way each time there will be no need for intermediate charging or fast charging,” he said. “So lead batteries will commonly be used in environments such as shopping centres, large warehouses and airports.”

He adds that lithium-ion batteries tend to be preferred in harsh environments where a lightweight machine is required.

“Since last year we have seen a big increase in requests for lithium ion batteries which can be charged very quickly and allow for intermediate or opportunity charging,” he said. “These processes will cause lead batteries to sulphate, but lithium batteries have been developed to allow this which means a machine powered with Li-ion can operate for three shifts without any problem.”

Safety should always be a concern, and care must be taken to choose the right environment for charging and maintaining batteries, according to De Soete. “However, lithium ion batteries may be charged anywhere because they are emission-free.”

He says the customer’s battery choice should take into account the type of industry in which the cleaning machine is operating. “For example, all batteries used in the food and pharmaceuticals industries should be sealed in order to eliminate the risk of any liquid being spilled.”

And it is also important to consider where the machine will be used and how intensively it will be employed, says De Soete. “For example, will the battery be deeply discharged, or will the shifts be short? For how many shifts will the machine need to run, and will fast-charging be required? Will the operator ensure a good level of maintenance, and in what temperature conditions will the machine operate?”

The environment that needs to be cleaned typically dictates the type and size of the floor machine required to clean it, says Trojan’s OEM sales manager Thomas Weiss. “If you need to clean a small, compact area you will want a machine that is easy to control and move around,” he said.  “And if you are a mobile cleaning service you will require a smaller machine that you can transport to various locations.

“On the other hand, larger machines with more battery capacity will be employed to meet the longer run-time requirements of facilities such as shopping centres, airports, hospitals, universities, entertainment centres and warehouses since these have large surface areas.  Longer run-times require more capacity – and this translates into larger batteries.”

He says flooded lead acid batteries are particularly popular in cleaning because they may be used for any floor cleaning application. “They are also the most economical energy storage device available,” said Weiss.

“However, due to concerns of possible spillages resulting from the machine tipping over – along with issues concerning the gas produced from charging the flooded lead acid batteries – sealed batteries may be preferred in areas such as schools, hospitals and other public areas,” he said. “Sealed lead-acid or AGM batteries contain acid that is absorbed in the glass mat separator, making the battery non-spillable.

“And AGM batteries generate a very small amount of gas when charging compared with flooded lead acid batteries.”

Trojan offers flooded lead acid, AGM, gel and lithium-ion options. Its latest launch is the lightweight Trillium lithium-ion battery which has built-in diagnostics and is suitable for use in any environment, according to Weiss.

Narrow, restricted areas need to be cleaned using a lightweight machine that is easy to transport, says IPC communications manager Gabriella Bianco. “Similarly an open-plan office space with multiple desks, chairs and electric cables will also require a compact and manoeuvrable machine powered by a lighter battery,” she said.

“On the other hand, longer periods of autonomy will be required when cleaning a large shopping centre, warehouse or airport. Here a big battery with a corresponding charger package will reduce recharge times and maximise runtimes.”

According to Bianco machines powered by flooded batteries should only be used in areas where the recharge point is in a well-ventilated open space in order to minimise the risk of explosion.

“However, flooded batteries have the advantage of being able to withstand a higher number of loading cycles than other products and they last longer than gel or AGM batteries,” she said.

Appropriate charging

Safety should be a key consideration in certain industries, she adds. “In environments where there is a fire risk such as in the mining, fireworks and electronics industries for example, there should be detailed rules on the appropriate charging location,” said Bianco.

Most IPC scrubber dryers are powered using the company’s Double Battery Life technology which is said to optimise charging cycles and increase battery life by up to 100 per cent.

So, how far does the environment in which cleaning takes place influence the choice of battery power? The application is actually more important than the environment according to Kärcher’s Cassio Murillo, while Trojan’s Thomas Weiss says the time required to clean the given area should also be considered. “It is the size of the machine – plus the required run-time - that will dictate the battery size, system voltage and battery construction,” he said.

However Martin Walsh from EnerSys claims it is the size of the area to be cleaned plus the size of the machine to be used that will generally dictate the type of battery. And IPC’s Gabriella Bianco concurs. “The size of the cleaning area will determine which machine will be used and how it will be powered – so in other words, the environment is the key point,” she said.


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