Are Dewalt and Hercules or Bauer Batteries Compatible?

People often ask me if Harbor Freights in house brands Hercules and Bauer 20V batteries are compatible with Dewalt tools or vice versa. I can see why the question makes sense since they are all using slide pack batteries with the same voltage branding of 20V max which is really 18 volts just like Makita, Bosch and Milwaukee batteries.

General Rule of Thumb is that Batteries From Different brands are not Compatible As Is

As a simple answer, in most cases the answer is no. This is because the general rule of thumb for batteries from different brands is that they are not cross compatible as is for a few of reasons UNLESS THERE IS MODIFICATION TO THE BATTERY OR AN ADAPTER. I will list them below.

Incompatible Sliding Rails and Contacts

No matter how seemingly similar two different batteries may appear, each manufacturer has made sure that their battery is not compatible with other brands, even if the brand is one that they also make tools for. For example lets look at the Stanley Black and Decker family as they have Black+Decker 20V batteries and they also make Dewalt 20V batteries. This is because both of those brands are made by the Stanley Black and Decker parent company. Although both batteries appear very similar in shape and design and even feature similar sliding rails, both systems offer a different set of contacts in the form of differences in the rails such as notches, bumps and even different number of electrical contacts. A simple variation in the sliding plastic rails can make batteries incompatible with other brands tools. Bumps located in certain parts of the sliding rails also makes for incompatible systems. A different number of electrical contacts easily ensures two different systems are not compatible. Even when two systems have the same number of electrical contacts, the electrical contacts many times are not in the same spot as other brands making an incompatible mismatch.

In some cases battery contacts do work together with mismatched brands however there must be some modifying to the battery slide rails to get it to fit correctly such as grinding a way a notch or adding a groove. In some cases this works but you do run the risk of voiding your warranty so do this at your own risk and do your research beforehand. You can also use adapters in some cases – more info on that below.

Smart Electronics Communicate Between Tool and Battery

Some of the newer batteries and cordless tools have smart electronics that communicate between the tool and the battery. Often times this is for monitoring things like overload protection in the tool and overheating of the batteries or other things that make sure the tool and battery are always running optimally. These smart tools and batteries communicate with each other and will only work if the same brand tool is connected to the same brand battery.  Incompatible contacts makes nearly all batteries incompatible with other brands systems however even if you try to hack incompatible contacts by dremeling away bumps or adding notches and also rigging them using wires and alligator clips, all attempts fail because of the electronic chips inside the battery notices that it is not connected to the other brands tool so it doesn’t work. However there is an exception to this as there are adapters that let you use two incompatible brands batteries and power tools with an adapter and they seem to work. More on that below.

Dewalt, Bauer and Hercules batteries tested for cross compatibility – they don’t match physically

Youtuber Sean Carlin Designs, which weve seen a few of his videos here on Tool Craze, has attempted to see if Dewalt, Hercules, and Bauer batteries are cross compatible in the above video and his Hercules 20V videos. They are not because of incompatible contacts due to notches and bumps and also differing number of total contacts within each system. So no, you’re Dewalt battery will not work on a Bauer tool nor will it work on a Hercules tool and vice versa. It’s already been tried and they don’t fit.

Dewalt, Bauer and Hercules smart electronics do not communicate with each other – this has been tested as well

Youtuber Sean Carlin Desings in the above video also Jerry rigged the Bauer battery with nails to touch the battery contacts and alligator clips to connect the battery contacts with the ones found on a Dewalt tool. Nothing happened when he pressed the trigger on the Dewalt tool. He then tried the same Bauer battery rigged up the same way to a Hercules tool and this time around the light turned on the tool but it still did not run the tool motor.

The simple answer is that the chips inside each tool and battery did not verify each other so it’s a no go. Smart electronics wins this battle. So even if you were to dremel away the batteries bumps or add notches, these tools and batteries would still be incompatible due to smart electronics.

EXCEPTION To The Rule – Adapters

Now the marketplace is full of battery adapters that let you connect x brand battery with z brand power tool and they appear to work well. I’m not sure how they bypass the smart electronics but many people have made their own and you can even buy them outright on places such as Ebay and Amazon. I haven’t yet seen any adapters to use famous brand power tools with Harbor Freight in house brand batteries like those from Bauer or Hercules but that doesn’t mean there aren’t any now or won’t be in the future, I just haven’t seen them personally.

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I custom made an adapter so I could use the Hercules 20V battery with an old Craftsman 19.2 volt drill. there was only a +&- connector and it worked with no problems. So your review isn’t totally true as far as I’m concerned.By the way I’m an Electronic Tech with over 34 years experience.


re: “…use the Hercules 20V battery with an old Craftsman 19.2 volt drill.” Aside from the fact that some newer tools have “smart circuitry” intended to allow them to work only the same brand packs, there’s another aspect to this. With any newer cordless tool/battery system that has the battery protection circuitry in the tool rather than the battery pack, even if the newer pack will power an older tool (that used NiCad or Li-Ion packs), there is still a risk of over-discharging the new Li-Ion pack, because this combination has no over-discharge protection. If they’re like DeWalt, Milwaukee and… Read more »

Justin Benz

I recently made a video about using Dewalt tools with harbor freight/Bauer batteries. Check it out:


Um, your YouTube analytics may be a bit off. Anyway, I like powertools but am new to using them. Just bought a cheap, cordless orbital sander from Harbor Freight to sand down a picnic table. It’s lightweight and perfect for my small hands however the battery died after 40 min. Went online and found all kinds of 20VAH batteries sooooo much cheaper and compatible with Black and Decker and that’s how I found YOU! Loved the intro, but hey, there are soooo many women out there willing to broaden their minds, and try new things including reburbishing furniture, just like… Read more »

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