The voltage of cordless power tools has been edging upwards in recent years, with 40, 54 and 80V products recently catching the eye. Although many suggest these cordless tools offer comparable power output to a corded piece of equipment, why exactly is voltage important?
Voltage indicates the maximum energy potential of the cordless tool’s battery and serves as the force to make current flow. For this reason it is always worth assessing both voltage and amp-hours (Ah) when comparing the battery specification of cordless power tools. In terms of higher voltage batteries, the premise of this offer is the ability to perform work requiring higher torque, which applies greater force, while placing less strain on the battery.
Explains Kevin Brannigan, marketing manager at Makita (UK) Ltd: “Higher voltage equates to more power and, to meet market demands for greater cordless power and recognise the needs of professional contractors, we expanded our cordless portfolio with the introduction of our 40V Max and 80V Max [2 x 40V] XGT series. This cordless tool and Li-ion battery platform produces greater power for high-demand applications, offering performance that is comparable to petrol or mains-powered machines. As the world is now going cordless, we are looking to offer as many products as possible working from our battery-based systems.”
TRANSITION TO BATTERY POWER
Although XGT 40 V Max batteries look similar in size to existing 18V LXT batteries from Makita, the assertion of the former is to meet industry demands as the market pushes for the transition to battery power, without compromising run-time or charge time.
“Similar to our 18V LXT battery platform, XGT 40V also benefits from Makita’s smart system, which allows digital communication between the battery and the charger, and the battery and the tool,” says Brannigan. “This keeps batteries protected during use and when charging, as issues such as over-discharge and overheating are identified and quickly rectified, thus preventing damage. As a result, charge times are improved. For example, it takes just 28 minutes to fully charge a 2.5 Ah XGT battery and 45 minutes for a 4.0 Ah XGT battery, improving productivity thanks to the reduction of downtime.”
So, why does Makita not opt for higher Ah values; there are many batteries on the market with values up to 12 Ah? Well, although the company admits that technically there is nothing wrong with higher Ah values, it does suggest there are certain disadvantages. For instance, batteries with high Ah values are often larger and heavier, as well as being more expensive and typically take longer to charge. Makita says its 2.5 and 4.0Ah options provide the ideal ratio of charge time to run-time. From a portability perspective, the XGT 4.0Ah battery weighs 1 kg, while the XGT 2.5Ah battery comes in at 0.7kg.
When a battery is fully charged, it has a higher voltage. A Makita CXT 10.8V battery, for instance, has an unloaded voltage of 12V, thus the 12 Volt Max name, while the XGT battery has an unloaded voltage of 40V, hence 40 Volt Max.
The company says there are so many LXT batteries in circulation that 2x18 V LXT products will continue to exist and it has no plans to stop manufacturing these tools. However, for users who opt for weight and compactness of the battery, Makita insists that XGT is the ideal option.
Put simply, the XGT battery, in combination with new brushless motor technology, brings demanding applications within the range of cordless power tools. The Makita XGT line-up includes hammers, nailers, grinders, saws, drills, screwdrivers and wrenches. With the 80V Max XGT series, having two 40 V batteries on board means even more power for heavy-load applications. According to Makita, 80V of power allows XGT cordless equipment to rival corded tools and gas-powered equipment.
Of course, many will want to know if they can use their LXT batteries on an XGT power tool, or vice versa? The answer is no, unfortunately, LXT and XGT batteries are not cross-compatible. Makita has created XGT as a stand-alone platform to handle applications where greater power is required. The long-term view is to replace mains corded tools and facilitate a truly cordless jobsite. Makita’s LXT platform will remain in place and the company says it will continue developing LXT products moving forward. (For those wondering, there is no possibility of charging XGT batteries on an LXT fast charger, although with the purchase of an adapter, users can charge LXT batteries on an XGT fast charger. In such cases, the charging performance is similar to an LXT fast charger.)
END DAILY FRUSTRATIONS
Traditionally, when compared with corded power tools, even the most efficient cordless system provided a compromise between increased portability and reduced power, and between greater ease-of-use and reduced run-time. DeWalt, part of Stanley Black & Decker, is therefore another power tool manufacturer to recognise the daily frustrations that these limitations cause, which is why the company has engineered the XR FLEXVOLT system.
The XR FLEXVOLT is a convertible 18/54V Li-ion battery. In other words it is completely backwards compatible with existing 18V DeWalt products, with the option to amplify its voltage to 54V for use on bigger power tools. Therefore, XR FLEXVOLT batteries can power any existing 18V XR saws, grinders, drills, wrenches, screwdrivers and nailers, and make use of existing chargers.
The two battery technologies are fundamentally different in make-up. When fitted to 18V XR tools, the cells inside the battery link in parallel: five cells in a series (5 x 3.6V = 18V) multiplied by three strings in parallel (3 x 4Ah = 12Ah) = 216Wh. In contrast, when fitted to XR FLEXVOLT tools, the cells inside the battery link in series: 15 cells in a series (15 x 3.6 V = 54V) multiplied by one string in parallel (1 x 4Ah = 4 Ah) = 216 Wh.
A pertinent question here is, does increasing the power of the battery to 54V mean less runtime? “Absolutely not,” states Markus Rompel, director of engineering at Stanley Black & Decker Deutschland. “The voltage and amp-hour define the overall capacity of the battery. It’s equivalent to the size of tank on your car, which is the capacity of how far you can drive. So running the tool on 54V means basically you are more efficient and have more power available. As a result you can drill more holes in a shorter period of time, for example.”
For older technologies, such as NiMH and NiCd, deeper discharges permit the batteries to sustain a bigger energy capacity for longer. However, there is no such need with the latest Li-ion batteries, although as a point of note, users should not run these battery types until completely empty. Instead, the advice is recharge after use, regardless of the charge level remaining. There is no possibility of damaging the unit’s performance from charging at the end of every shift.