Battery equipment, a resource for gardening

Electric powered equipment is lighter, more manageable and products less noise and fewer vibrations compared to traditional models, all to the advantage of the comfort of the operator. Battery powered equipment for the maintenance of greenery is certain to become more popular thanks to innovative technologies which enhance safety and environmental sustainability. Hedge trimmers and mowers can be efficiently powered by electric motors with performance and efficiency which are no less than what traditional power provides

Battery powered machinery and equipment has been available for some time but only in recent years have these applications reached levels of performance meeting the needs not only of hobbyists but also of the operations of professional groundskeepers thanks to the arrival of lithium-ion batteries and increasingly sophisticated electric motors with efficiency of up to 90%. Thus many manufacturers are now marketing these types of machines. The machines for which battery power has risen to the fore are those carried by the operator, these are chainsaws, hedge trimmers, leaf vacuums and blowers, brush cutters, strimmers, shears and the like. There is no lack of applications for ground machines, pushed and self-propelled, and especially for mowers.

 

The advantages

Compared to internal combustion engines, with equal performance, battery power offers great advantages for the operator as regards the environment and operating costs.

Electric machines are lighter, more manageable and produce less noise and fewer vibrations all to the advantage of the operator. The noise level produced by a battery powered machine  is generally 10-12 dB(A) less than that produced by a gasoline engine at the same power. This is a significant difference because a reduction of 3 dB (A) corresponds to lowering the noise level by half whereas a reduction of 5 dB (A) equals lowering noise by 1/3. Also the reduction of hand-arm vibrations is significant, down by as much as 50% compared to gasoline engine models. This means lowering the prospect of ostearticular or muscular problems due to prolonged exposure to vibrations. Another highly important feature is that these machines do not produce direct CO2 emissions, hothouse gases or particulates in the air. The result is that these machines do not cause environmental pollution but respect national and European Union norms while making certain the operator is not inhaling toxic fumes.

The price of a battery powered machine is usually higher than an equal powered gasoline engine model but the running costs of fuel consumption mean that a larger investment is quickly paid off. Internal combustion engine machines carried by the operator, brush cutters or chainsaws, consume gasoline at the rate of 1-1.5 liters per hour so the cost of operations of 60 hours over a year comes to 60-80 liters, plus the consumption of oil, to take the cost to around € 100.00. At the same the power for machine run off batteries for the same number of hours takes the cost of recharging the batteries to only a few euros.

Considering that the duration of the use in these two cases is virtually the same, it must also be pointed out that the maintenance costs of the battery machine is less than that for the internal combustion engine models so overall, the choice of an electric model also carries a financial advantage.

Account has to be taken that a battery machine is operated with a keyboard, turned on and off simply by pressing a button for greatly facilitating operations and, in comparing the weight of the two of the equal types of machine, the battery model weighs about half the weight of the internal combustion engine machine. 

 

The batteries

Rechargeable lithium-ion batteries have three components: the anode releases electrons to power the equipment the battery is applied to; the cathode absorbs the electrons; electrodes, where ions move between electrodes though the separator that acts as an insulator for electrons. The electrode of a battery that releases electrons during discharge is called the anode; the electrode that absorbs the electrons is the cathode.

Lithium is the lightest element and the least solid element and has high energy density. These batteries run our cellphones, electric automobiles and a host of other devices including, as illustrated in this article, equipment for grounds keeping. Compared to nickel cadmium batteries, they have high energy density and a longer life cycle in that they maintain 75-80% of their charge over as many as 800 recharging cycles. This means their capacity decline only slowly over their life cycle.

Moreover, these lithium-ion batteries do not suffer from the memory effect as do other types of batteries. This effect applies when recharging is done before the battery is completely discharged. It can happen that a battery up for recharge has used only 70-60% of its charge and the 30-40% of energy remaining is not considered so the recharge is not completed. During charging and recharging a batter the temperature must be constantly controlled to make certain the operation is optimized and trouble free.

Summing up, it can be said lithium-ion batteries have an energy density well over that of traditional batteries to allow much greater autonomy, they last longer and are recharged more quickly. According to the specific case, they can be recharged in 30 minutes or up to 2 hours using their specific battery charger. These batteries can be mounted inside the equipment or carried on the outside in a backpack or attached to the belt of the operator. Various manufacturers have decided to produce batteries which work for various pieces of equipment. This means, for example, that there is no need for batteries for a chainsaw, others for a leaf blower and yet others for a hedge trimmer because the same pack can power these three or more pieces of equipment. 

Putting the batteries in place is quick and easy. Their power normally last about 45 minutes. The batteries come with different voltages (Volt-V) and differing intensity of current (Ampere -  A). For machines carried by the operator, the batteries mounted inside are from 18 V to 24 V and up to 48 V with differing amperes for each, 2.5 Ah and 5 Ah, for example. To prolong use with the same machine, two batteries can be used, one to replace the one which needs a recharge. Backpacks or belts for carrying batteries are required for professionals at work for an entire day because this solution ensures a very high energy capacity for operations. 

Chainsaws

Battery powered chainsaws with cutting bar lengths of 30-35 cm are fairly widespread. These models frequently pack batteries from 36 V – 3 Ah (o 4 Ah). The performance of these machines is comparable to that of internal combustion models powered at 1.5 kW. The cutting bar lengths of 30-40 cm the battery capacities used are, for example 48 V-5Ah.

Hedge trimmers

The most frequent solution for hedge trimmers is the use of 36 V-1.6 Ah batteries for models with a 50 cm blade and larger capacity batteries for those with 60 cm blades, 36 V-2.4 Ah for example. The versions with backpack batteries, which can be chainsaws as well as hedge trimmers and other pieces of electric equipment, require much higher capacity batteries such as 44 V-23.2 Ah  and up to greater than 1 kW. Electronic control ensures the management of the ion elements in the batteries’ lithium. The time taken to recharge these batteries is obviously longer and can require 5 to 10 hours or even longer.

Mowers

As explained above, there can be recourse to batter power for machines other than those carried by the operator, for push and self-propelled machines for the maintenance of greens. In the first place, these applications are for push mowers with the operator on the ground. The standard for robotic mowers is obviously a battery powered electric drive. The battery models with the operator on the ground are widespread. The cutting width varies from 35 to 50 cm. The performance of these mowers is comparable to various internal combustion engine models with power of around 1.5 kW and are suitable for areas of less than  500 m2. Less common are these applications for ride-on mowers.

 

Concluding remarks

The use of batteries for the maintenance of lawns will undoubtedly increase thanks to innovative technological features enhancing the benefits of safety at work and environmental sustainability. These characteristics are especially favored for the management of public greens and, more generally, in all conditions in which the sustainability of the environment is a strong point.