Ryobi’s relatively new line of USB Lithium cordless power tools requires the use of a proprietary battery pack. The same is true for Milwaukee Red Lithium USB.
There are many 3.6V and 4V Max cordless power tools which have built-in and non-replaceable rechargeable batteries.
A lot of tool enthusiasts often complain in unison – why can’t such tools simply use bare Li-ion battery cells in popular sizes, such as 18650 and 21700?
My working theory is that proprietary batteries make it easier for brands to offer consistent performance and charging solutions, and convenient availability for replacement batteries. Proprietary batteries reduce the hassle for most consumers.
For example, not all 18650 Li-ion batteries provide the same level of performance, and it would be too easy for users to select cells mismatched to their tools’ power requirements.
Prompted by readers to start exploring Li-ion rechargeable flashlights, I bought a flashlight that works with 16340-sized batteries. Unsure of its power requirements, I asked the maker for recommendations. The battery they could personally recommend has been long-discontinued, and they could only point me to brands that other users have chimed in positively about. That helped a little, but not really as the battery brand in question has several battery sizes and styles in that size, each with difference performance profiles.
Selecting a charger was a separate hassle.
At the enthusiast level, one can usually figure things out with a bit of research and Q&A.
Tool brands can’t put that burden onto users; it’s in their interest and most users’ benefit for tool brands to offer customized cells. If you need another battery for Ryobi USB or Milwaukee RedLithium USB tools and accessories, you can find the Ryobi at Home Depot, and the Milwaukee at any store their USB tools are sold.
But, it seems there are other reasons on top of that.
In 2021, the US Consumer Product Safety Commission (CPSC) issued the following safety warning: Serious Injury or Death Can Occur if Lithium-Ion Battery Cells Are Separated from Battery Packs and Used to Power Devices.
It starts off with:
The U.S. Consumer Product Safety Commission (CPSC) is warning consumers not to buy or use loose 18650 lithium-ion battery cells. These cells are manufactured as industrial component parts of battery packs and are not intended for individual sale to consumers. However, they are being separated, rewrapped and sold as new consumer batteries, typically on the Internet.
The warning continues, with mention about how some loose 18650 battery cells are potentially hazardous when handled, transported, stored, charged, or used to power devices.
Rechargeable lithium cells without proper protection that are not installed in a device or as part of an integral battery (“loose cells”) are potentially hazardous to consumers when handled, transported, stored, charged, or used to power devices. Specifically, these battery cells may have exposed metal positive and negative terminals that can short-circuit when they come into contact with metal objects, such as keys or loose change in a pocket. Once shorted, loose cells can overheat and experience thermal runaway, igniting the cell’s internal materials and forcibly expelling burning contents, resulting in fires, explosions, serious injuries and even death.
In addition, thermal runaway can occur in loose cells if consumers use them in inappropriate chargers that allow for charging beyond the cell’s specifications. Unfortunately, a growing number of small consumer products, such as vaping devices, personal fans, headlamps, and some toys, are using loose 18650s as a power source. CPSC is working with e-commerce sites, including eBay, to remove listings selling these loose cells.
Do not use loose 18650 lithium ion cells that are separated from battery packs. They are often misused as a stand-alone consumer battery, but do not have protection circuits.
This isn’t a straightforward warning. It talks about consumer products that require the use of loose Li-ion cells, but also of battery cells of ambiguous origins.
These cells are manufactured as industrial component parts of battery packs and are not intended for individual sale to consumers. However, they are being separated, rewrapped and sold as new consumer batteries.
Are they talking about 18650, 21700, and other types of Li-ion batteries in general, or batteries parted out from battery packs for resale?
The US CPSC warning points to their general battery guidelines, which looks to have been published a couple of years ago, seemingly following the rash of self-balancing hoverboard fires.
Components and battery-powered products comply with applicable voluntary standards;
New components and products that are not yet subject to voluntary standards be designed considering the best practices from similar voluntary standards;
Battery-powered products be designed with a system approach addressing thermal protection, charge and discharge protection , and use in product, including:
- Cells suitable for intended loads and conditions and manufactured with good quality control
- Battery packs with proper Battery Management Systems, including charge control, short-circuit protection and cell balancing
- Chargers that comply with applicable voluntary standards and are suitable for product
- End-product systems (including cells, batteries, chargers, and product) are tested together for safe function and appropriate conditions.
I haven’t been able to navigate OSHA or UL guidelines, but I would bet they have similar requirements.
I understand that OSHA-approval for jobsite use requires that tools and products be certified by UL or another nationally recognized testing laboratory (NRTL). Is that possible if rechargeable Li-ion batteries can be used other than those a tool is kitted with?
Is there any user-replaceable bare-cell device that is UL listed, or otherwise NRTL-certifed?
Some flashlight makers utilize replaceable rechargeable Li-ion cells that feature built-in USB charging ports. Often, I have found, it’s difficult to source comparable bare cells; most don’t make it easy to select replacement cells other than their own.
It would be fantastic if you could roll up to a project with a flashlight, digital level, heated accessory, cordless screwdriver, and other such devices powered by customized (and protected) 18650-sized Li-ion cells, from all different brands that can work with the same off-the-shelf protected cells.
But that’s not happening.
I thought this because of “it’s best for the brand and majority of everyday users” considerations, but it seems there are governing body and perhaps UL or test lab guidelines that must also be navigated.
Let me ask you a question. What would you do if you were a tool brand?
Some of you will say “I’d let them use whatever battery they want.” Okay – how do you advise a first-time user about which battery and charging options are available?
It’s a messy debate. I can see both sides of the coin.
The question to ask is – what needs to happen before 18650 and other Li-ion battery sizes are treated in the same manner as AA or AAA primary or rechargeable cells (such as NiMH)?
Until that happens, there are two choices – built-in non-replaceable batteries, or proprietary battery packs.
The enthusiast flashlight industry has moved towards rechargeable Li-ion batteries, but how many are UL-listed? How many products that use bare 18650 cells (protected or not) are sold at Home Depot, Lowe’s, Target, or Walmart?