We have seen the future, and it’s electric. And so quickly and certainly is it going electric that we predict that within the next couple of decades the only place you’ll see the small two- or four-stroke petrol engines such as commonly power lawnmowers, brushcutters and chainsaws today will be in a museum.
The technology that is making this silent, pollution-free revolution possible is the lithium-ion battery, about which you can read elsewhere in this edition. The superior charging ability of Li-ion batteries is well-known, and in small items such as cellphones, watches and cameras they have become commonplace.
Detractors of rechargeable battery-power point to the high cost of the batteries and chargers and the argument holds some merit at present.
But Li-ion technology is developing rapidly and the batteries are becoming more efficient, with their prices dropping dramatically every year. At the upper end are the large units powering electric cars such as the Tesla and Nissan’s Leaf, and in Elon Musk’s elegant domestic solar power pack that will enable households to live wholly or partially offgrid without disrupting or defacing the dwelling.
And now progressive manufacturers of power equipment are seeing the benefits of Li-ion power for their machines.
Stihl, for example, has developed three ranges of garden and farm machines, with different specifications, to suit homeowners with the smallest of townhouse gardens, those with more extensive properties to maintain, and full-on commercial or professional users such as farmers, landscapers and municipalities.
Across each range the battery packs are interchangeable between machines and the chargers universal to the particular range. Thus, in a domestic situation for example one buys a small Stihl chainsaw, a string trimmer, a blower and a hedge trimmer, one or two batteries and a single charger.
When one has finished pruning the branches of one’s trees with the chainsaw, or cutting up a few logs for firewood, one removes the battery from the chainsaw and slides it into the string trimmer before neatening the edges of the lawn. With that task completed one removes the battery again and slides it into the blower to clean up the trimmings. And so on.
Much the same system is employed by Makita in their power tools, which are proving popular with contractors such as electricians, repairmen and plumbers who find not having to run out extension cords to run their tools up in ceilings and workspaces a boon. Such users will buy a single battery powered tool, say a drill, and a clutch of batteries and chargers. During the course of a work-day they simply replace the depleted batteries with freshly charged units to carry on working, charging the depleted batteries overnight for the next day’s work.
Depending on the make of tool the intended use and the size of the motor, the batteries will be 12V, 24V, 36V or 48V types, and some of the more powerful tools will require two at one time, for example 2 x 48V = 96V, to run.
At the top end, the professional tools are powered by battery backpacks with the machines attached to cables.
Stihl, for example, has a range of straight-shaft brushcutters and clearing saws every bit as powerful as the large petrol-powered machines. The battery packs contain sufficient charge for a day’s work, thus making them suitable for use by parks departments, farmers and landscapers.
And, in true Germanic style, Stihl has some impressive arithmetic to show that the initial outlay on the machine and battery pack is very quickly recouped in the saving on fuel cost over the machine’s lifetime.
And that, despite the eye-watering cost of the battery packs ~ north of R12 000 in the case of the bigger units. Having said that, the cost of lithium-ion batteries is decreasing steadily, while their efficiency is improving at the same time.
Apart from savings in operating costs, battery-powered tools have other significant benefits.
First and foremost is the saving in the cost of petrol and oil, and the associated benefit of not having to store and cart around canisters of potentially dangerous fuels.
Then there is the benefit of operating a pollution-free machine, for despite many advances in design in recent years two-stroke engines are notoriously inefficient burners of fuel and thus disproportionately guilty of air pollution.
Thirdly, if you have only ever used a petrol-powered brushcutter you will be forgiven for admitting that you have never heard the “whishing” noise the string makes as the head spins. That’s because the noise of the string is drowned out by the noise of the engine. An electric unit, by contrast, has no engine noise, the only sound being the movement of the string head. As a result, you need no ear protection to operate a battery powered brushcutter, only safety glasses. That’s one less item of PSE (personal safety equipment) you need to worry about for your workers, and one less point for the OHSAct inspectors to get nit-picky about.
And if you live in close proximity to your neighbours, they won’t need earplugs either every time you trim your lawn.
Explainer: Li-ion deconstructed
Like all batteries, a lithium-ion battery contains an anode and a cathode separated and yet conjoined by an electrolyte.
Unlike your car battery where the electrolyte is a liquid (battery acid diluted with distilled water) the electrolyte of a Li-ion battery is either a liquid polymer or a solid of some sort.
The anode is usually lithium, graphite or a variety of lithium alloys or silicon.
The cathode, by contrast, is usually a lithium metal oxide with oxides containing nickel and cobalt being the most studied and most stable.
To remind you of your high school chemistry, the formulae for these compounds are LiMn2O4 or LiCoO2. Lithium, to remind you, is element number 3 on the Periodic table, lying between helium and beryllium, and Cobalt element number 27, lying between iron and nickel. Lithium is thus the lightest metal and in its natural state quite unstable.
But it is cobalt that is the elephant in the room as far as Li-ion battery technology is concerned.
Half of the world’s known deposits of cobalt are found in the Democratic Republic of Congo, with other deposits found and mined in Zambia and the Central African Republic. Cobalt is also a by-product of platinum and nickel mining.
And here’s the problem: of the cobalt mined in the DRC, industry observers say that up to 20% is mined by hand, the small operations being both physically dangerous and exploitative of the workers, who are often children.
Thus, activists have taken to raising awareness of the nature of cobalt mining as a fertile ground for exploitative child labour and have started making calls for users of Li-ion batteries to insist, and to certify, that the cobalt used in their batteries be ethically sourced.