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Executive Report: Lithium-ion under test Phil Mist, EHN’s power tools specialist, assesses Milwaukee’s new cordless drilling hammer to see if it lives up to the claims made for it. I have been keen to test Milwaukee’s V28 SDS Plus drilling hammer for some time. Its lithium-ion batteries are said to give day-long operation, reliability and reduced maintenance, all factors that should appeal to hirers. The 28V machine is claimed to have a maximum drilling capacity of 26mm. It has three modes and has a single blow energy rating of 3.2J – considerable for a battery powered tool. The charge time is said to be one hour, which was found to be more or less correct, but depended somewhat on the temperature of the battery when inserted into the charger. EHN’s tests comprised drilling a series of holes using both the V28 and a rival SDS Plus hammer drill powered by a NiMH battery, into a block of 45Nm concrete. Standard SDS Plus drill bits were used in a variety of sizes, all of which were within the rated drilling capacity of the tools. The overall performance of the two was then compared. The smallest drill bit used was a 6.5mm diameter x 160mm long SDS Plus bit with a drilling length of 95mm. Many holes were drilled vertically downwards into the concrete in rapid succession, all to the same depth. On each occasion, the time taken was measured, and an average was finally established. Manufacturers of lithium-ion cordless tools typically claim a 30% improvement in performance compared with NiCad or NiMH powered tools. EHN’s tests showed a saving of at least 25% in time taken per hole. Save six seconds on each 6.5mm hole and you save ten minutes per day over 100 holes. Over a number of sessions of repeated drilling several days per month, this adds up to a tidy sum saved in labour charges alone. A 10mm diameter x 260mm long bit with an overall drilling depth of 190mm was tried next. The V28 substantially outperformed the competitor machine, again with an average 25% saving of more than 12 seconds per hole. Using any machine for a reduced length of time can have Health & Safety benefits if it offers approximately the same level of noise and vibration emissions when compared with existing machines of a lesser performance. Finally, the V28 was fitted with a 22mm diameter x 250mm long bit with a drilling depth of 160mm. Here the difference in performance was even more marked, with a saving of more than 30 seconds per full depth hole. Whilst I would normally recommend a mains powered electric SDS Plus hammer drill for drilling such large holes on a regular basis, there are times when a battery powered machine is the only option. In such cases, the V28 is ideal. The V28 test sample was found to weigh 4.4kg (Milwaukee claims 4.3kg), which compares favourably with current 24V models weighing typically 3.8-4.1kg. The battery itself is almost identical in weight to some 18V NiMH and NiCAD batteries, yet gives substantially more power. It also suffers from fewer problems caused by the so-called ‘memory’ effect. I must point out that I was taken completely by surprise on the first occasion the battery went flat. One minute the machine was performing normally, and then it stopped dead. I thought I had broken the tool. The V28 is certainly an improvement on NiCAD and NiMH powered SDS Plus hammer drills. It should be: it costs a lot more. Environmentally, it is streets ahead, containing no heavy metals. But the main reason I believe it will appeal to the hire industry is that it appears to be more robust and, since it has a better drilling capacity, it will not be ‘hammered’ as much on site. Other manufacturers are developing their own lithium-ion products. EHN will monitor the situation and report accordingly. • T
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258346 Executive Hire News › Archives › May 2006 › Executive Report › Lithium-ion under test
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