Let’s Talk Cordless Power Tool Battery Adapters


Like I always say “the freedom of cordless is amazing, but being tied to any one tool brand because of batteries sucks.”

Enter, third party battery adapters.

I don’t need to ask manufacturers if it’s okay to use their tools or batteries with adapters because the answer can be found in any tool manual. They all say the same thing in the Battery Use and Care section, which is to only use batteries and chargers specified by the manufacturer of the tool.

So what is the risk/reward?

The risk is adapters may break communication between the tool and battery disabling or limiting the full effect of the electronic protection system (EPS).

So the main risk is you burn out a battery or tool, or worse a battery explodes lithium juice all over your face. And when a tool or battery does fail you’ll never know if it was the adapter’s fault.

Potential rewards include, but are not limited to, battery juice to the head somehow unlocks mutant super powers, you can use whatever tools you want without buying new batteries or carrying multiple chargers.

What does an EPS do?

An electronic protection system protects the battery and/or tool from overloading, overheating, and over-discharge.

Overloading, according to Makita, means “The tool is operated in a manner that causes it to draw abnormally high current”. When this occurs the EPS kills power, stalling the tool.

Overheating, the enemy of runtime, will also trigger an EPS to shut down the tool.

Over-discharging of the battery can reduce its rechargeable lifespan or even turn it into a brick that will no longer take a charge.

Let’s Look at a Few Systems


Milwuakee has Redlink Plus on many, but not all, of their currently sold cordless tools. For example, the 2630-20 6.5″ circular saw doesn’t have Redlink, nor list any type of EPS in the manual.

But their Redlithium XC and up batteries have Redlink built-in and word on the street is that protects them on non Milwaukee tools.

On a side note, in our comparison vids we’ve seen Milwaukee batteries on Milwaukee saws time themselves out 2-3 times more often than Makita and Dewalt on their respective 20V batteries.

It occurred to me that Redlink Plus is needed to protect Milwaukee batteries from Milwaukee tools as they dial-up their stuff to compete with DeWalt’s 60V and now Makita’s 40V tools that can run longer and cooler without timing out. But I digress.


Makita has STAR and says when Star batteries are paired with Makita tools with a star symbol, or yellow terminal, you get “added protection” because they can now communicate.

So do Star batteries prevent deep discharge through an adapter on non Makita tools? We’ll try and test that in an upcoming adapter vid and post it here, so stay tuned.


All DeWalt lithium ion tools have an EPS that will “protect the battery pack against overloading, overheating or deep discharge.”

So DeWalt batteries on DeWalt tools have protection but I’ve read somewhere in DeWalt’s literature that running their lithium batteries past the slow down point reduces rechargeable lifespan, so it seems there may be no low voltage shut-off in the battery itself.

I can tell you this, I’ve literally smoked a DeWalt 20V 3/8″ drill mixing thinset and the EPS didn’t do anything to stop that tool from overheating. I mean it was smoking hot and running a DeWalt battery so what happened with the EPS in that situation?

Bottom Line

The main risk of adapters seems to be the battery overheating or over discharging. I saw a vid where a guy showed sparks between an adapter and a tool and someone left a comment on a post saying they lost a battery when their adapter shorted.

So, if you’re worried about an adapted battery shorting out or heating up and exploding all over your face, I can’t tell you that won’t happen. For me they seem safe enough if used thoughtfully and I like/love them for certain tools.

Adapters I Use

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FirstPower Battery Adapter Converts Milwaukee 18V and DeWalt 20V Batteries to Makita 18V Tools.

Alian Battery Adapter for Dewalt 20V Batteries to Milwaukee 18V Tools

Alian MIL18DL Battery Adapter for Milwaukee 18V Batteries to DeWalt 20V tools.

Stay tuned for the upcoming adapter vid and let us know your thoughts in the comments. See ya!



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