Can You Use Harbor Freight Batteries On Craftsman Tools?

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As nice as it is to have a full cabinet of high-quality, name-brand power tools, actually buying all of those tools can be distressingly expensive, to say nothing of a complete package of both power tools and the battery packs necessary to use them. If you're looking to get Craftsman products, for example, a single 20V 4Ah battery pack will run you $119 if you purchase it at Lowe's. Unlike some brands like Milwaukee, which only deal to authorized retailers, Craftsman is one of the few major hardware brands that sells its tools and accessories on Amazon. Shopping there will offer some modest discounts, and Craftsman has some offerings you can get for less than $100. Tools and their accompanying batteries, however, will more often than not run up the price.

If you are hoping to get power tool accessories on a budget, Harbor Freight's offerings from in-store brands like Bauer and Hercules are certainly cheaper than the norm. Considering this, you might be thinking about purchasing a standalone Craftsman tool and supplanting the battery with one from Harbor Freight. Unfortunately, while the battery packs from Harbor Freight's brands have some superficial similarities to Craftsman's packs, subtle differences prevent the former's batteries from being attached to the latter's tools. It is technically possible to work around this limitation through third-party battery adapters, but using these unofficial products may hurt more than help in the long run.

The battery packs sold by both Craftsman and Harbor Freight's in-store brands have the same basic concept: An array of power cells are housed on the bottom of the pack, and the top has a panel with several divots concealing the power transfer terminal. You slide the battery on via the connecting rails, the terminals line up with the receiver on a tool, and the power starts flowing.

While the batteries are conceptually similar, the devil is in the details. If you take a closer look at the top panel on a Craftsman battery, such as the V20 4Ah model, and compare it with a similar battery from Harbor Freight like a Hercules 20V 4Ah pack, you'll see the differences. The Craftsman battery has four evenly-spaced divots covering its terminals, connector rails with a soft curve to them, and two small points sticking up out of the top. The Hercules battery, meanwhile, has four divots with a large space separating them into two groups, as well as connector rails with a much sharper angle to them.

These distinct designs are what make or break a battery's ability to connect. Because the rails on the Hercules battery are dissimilar, the pack wouldn't be able to slide and lock onto the receiver of a Craftsman tool. Even if you could secure the pack somehow, they wouldn't align with the tool's own power terminals because they are spaced out differently, meaning energy wouldn't be able to flow. The same is true for all other power tool batteries sold at Harbor Freight, whether they're from Hercules, Bauer, Warrior, or Atlas.

Despite these limitations, some power tool owners may still be determined to find a way to use an assortment of batteries on whatever tools they want. One primary way in which this is accomplished is through unofficial, third-party battery adapters sold on platforms like Amazon and eBay. These gadgets have compatible connectors on their tops and bottoms, allowing them to latch onto a battery and facilitate a connection to a tool from another brand.

There are several problems with these adapters, however. The first is that all adapters are strictly one-to-one devices. If you wanted to use a Hercules battery with a Craftsman tool, for instance, you would need a specific Hercules-to-Craftsman adapter, which also means it wouldn't work with any other battery brand sold by Harbor Freight.

The other, bigger problem is that using battery adapters disables a battery's natural protections. Within all power tool batteries, including those sold at Harbor Freight, there is circuitry that interfaces with a connected tool to optimize and regulate power flow, ensuring safe, proper usage. When you connect a battery to a tool with an adapter, though, that circuitry is bypassed, essentially forcing energy through unregulated. This could result in either underpowered performance or a dangerous energy overload that could end up burning out the tool's motor entirely. To make matters worse, if either your Harbor Freight battery or your Craftsman tool are permanently damaged while using an unofficial accessory, neither brand will show you any sympathy, as third-party accessories violate their warranties.