On June 21, 2016 at 8:30 am in Baltimore, MD, we witnessed the unveiling of DeWalt's FlexVolt technology. It brings never-before-seen mixed-voltage battery technology to the table and opens up even more tools for the wireless world. We've heard a lot of confusion about FlexVolt, so this article will go over the key details and capabilities of the technology so you can see why you may or may not want to take a closer look.
Hybris battery voltage revolutionized the DeWalt FlexVolt. Each FlexVolt battery supports an output of 20V Max or 60V Max. The tool tells the battery which mode to run in, so it's completely automatic for the user. Electronic control gives DeWalt the technology to connect the FlexVolt battery in two ways to extend run time on 20V Max tools or to provide more power in 60V Max (and occasionally 120V Max) tools.
FlexVolt batteries are currently available in four different sizes:
- 2Ah 60V FlexVolt (6Ah @ 20V)
- 3Ah 60V FlexVolt (9Ah @ 20V)
- 4Ah 60V FlexVolt (12Ah @ 20V)
- 5Ah 60V FlexVolt (15Ah @ 20V)
20V Max and 60V Max on the same battery – how?
The idea of battery pack wiring is fairly simple. You connect lithium-ion cells in series to increase the voltage. Connecting multiple rows of batteries in parallel provides greater amp-hours.
Wired for greater amp hours
By connecting five Li-Ion packs in series, you can get a 20V Max pack (or an 18V nominal pack). Each cell produces 4V max (3.6 volts nominal), which is doubled to 20 volts connected in series. The ~2.0 amp hours in each cell are not combined in any way, so the battery is a 20V Max, 2.0 amp hour battery, also known as a DeWalt compact battery.
You can then connect a second set of five units to the first using a parallel connection. Now the voltage remains the same, but the amp hours are doubled. This will create a DeWalt 20V Max 4.0 Amp Hour Battery. Add a third row of batteries in parallel and your 20V Max battery will get 6.0 amp hours.
Wired for higher voltage
If you were to remove the two parallel connections between the five battery packs and replace them with series connections, you would end up with batteries with a maximum voltage of 60V at 2.0 amp hours. This concept has driven the development of higher voltage systems such as the 40V Max in DeWalt's OPE and 56V and 80V Max batteries on other platforms.
Before the DeWalt FlexVolt, you had to select a hard configuration for the battery to run. If you want a higher voltage battery, you have to migrate to an entirely new platform that is not compatible with lower voltage systems. Another solution is to connect multiple batteries in series to double the voltage.
If you look inside a DeWalt FlexVolt battery pack, you'll find 15 Li-Ion cells and a wiring configuration for 20V Max and 60V Max power. Electronic communication between the tool and the battery tells the battery which set of wiring to run on. The DeWalt 15Ah FlexVolt Battery uses more cells – but the principle is the same.
Corded tools consume different amounts of power. A drill gets all the torque it needs from a 6 amp motor, while a miter saw needs a 15 amp motor to work properly. Each motor has an amperage rating, but power consumption is actually measured in watts (your electric bill always shows kilowatt-hours used).
With FlexVolt, use the 20V Max configuration for tools that consume fewer watts with smaller brushless motors. When higher power is required for larger brushless motors, you can put batteries in the FlexVolt (60V max) tool.
You can think of a lithium-ion battery as a fuel tank. It has a certain usable potential energy capacity. For DeWalt FlexVolt batteries, this is 108 nominal watt hours (nominal voltage times amp hours). The 9.0 amp-hour FlexVolt will have 162 watt-hours at launch. This tank drains through a combination of voltage draw and amp-hour draw (current). Multiply these two values to get the power in watts. In his research, DeWalt found that larger brushless motors run better at 60V Max and 120V Max than they do when they try to push higher amps at 20V Max. At the same time, all the tools they developed can be run normally under 20V Max.
The idea behind the FlexVolt is to create a cordless workplace that doesn't compromise on power and performance regardless of the tools used, without forcing the user to be tied to multiple battery systems.
Dos and Don'ts About Air Travel Safety
108 and 162 nominal watts (and higher) can actually cause distribution and air freight issues. At a capacity of 100 watts, the limit would be in effect based on the inherent risk associated with thermal runaway of Li-ion batteries, if they overheat and catch fire, usually due to a short circuit. We can carry smaller lithium-ion batteries on board if they are installed in equipment or packaged properly.
DeWalt developed a simple but effective solution. By locking the DeWalt flight adapter in place on the battery, the 108-watt-hour system is divided into three 36-watt sections and is certified safe for air travel. Its connection to the terminals helps prevent short circuits in addition to creating the battery separation required by the FAA.
Will the FlexVolt tools work with 20V batteries?
Can't. One thing to know about DeWalt FlexVolt tools is that they only work with FlexVolt 60V Max battery packs. While a FlexVolt battery can fit on and power a DeWalt 20V Max tool, this is not the case. DeWalt FlexVolt tools require the 60V output that only FlexVolt battery packs can produce.
DeWalt offers a variety of tools for the FlexVolt product line. They announce more and more every year. Here is a small sampling of some of the original FlexVolt cordless power tools along with MSRP:
DeWalt FlexVolt 120V Max Tool
- DHS716AB/T2 Fixed-Blade Miter Saw with Adapter Cord: $499/$649
- DHS790AB/T2 Sliding Miter Saw with Adapter Cord: $649/$799
DeWalt FlexVolt 60V Max Tool
- DCS575B/T1/T2 Circular Saws: $179/$299/$379
- DCS388B/T1/T2 Reciprocating Saws: $179/$299/$379
- DCS485B/T1 Table Saw: $379/$499
- DCG414B/T1/T2 Grinder: $179/$299/$379
- DCD460B/T1/T2 Stud and Joist Drills: $279/$399/$479
DeWalt FlexVolt 20V Max Tool
- DCL070/DCL070T1 Area Lights: $399/$499
- DCK299D1T1 Hammer drill and impact driver kit: $379
DeWalt FlexVolt Batteries, Chargers, Radios and Adapters
- DCB606 FlexVolt 20/60V Max Battery 6.0 Ah: $149
- DCB606-2 FlexVolt 20/60V Max Battery 6.0 Ah 2-Pack: $199
- DCB118 Fast Charger: $79
- DCA120 120-volt adapter: $49
- DCR025 Bluetooth Radio Charger: $199
- DCB1800B Portable Power Station: $399
- DCB1800M3T1 Portable Power Station with (3) 4.0 AH 20V Max Batteries and (1) 6.0 AH FlexVolt Battery: $599