Can You Use Harbor Freight Batteries On Ryobi Tools?

We may receive a commission on purchases made from links.

Amongst the major hardware brands, Ryobi is generally fairly well-regarded by users for its gadgets, power tools, and rechargeable battery systems. Of course, as with any brand that's well-regarded, that can translate into higher prices. A single rechargeable battery pack for one of Ryobi's ONE+ power tools can run you around $100 at Home Depot, and that's without factoring in the costs of the tools themselves. Whether you're a professional worker or just need some tools around the house, the fact of the matter is that not everyone can afford to drop several hundred dollars on such things at a moment's notice.

If you were looking to slash prices somewhere in the Ryobi equation, it would make the most sense to swap the battery out for a cheaper one so you still get the actual tool part of the Ryobi tool. For instance, the various power tool batteries offered by the in-house brands of Harbor Freight, such as Bauer and Hercules, are definitely cheaper than those made by Ryobi. Unfortunately, what you gain in savings, you lose in one vital area: connectivity. The batteries sold by Harbor Freight use completely different connection formats and thus cannot be attached to Ryobi tools. This could theoretically be circumvented with a third-party battery adapter, but using one of these could prove detrimental to your tools' health.

The majority of power tool batteries function in the same basic way: the main compartment on the bottom houses the actual power cells, while the power terminals on the top connect to a receiver on the tool to send power. These terminals are accompanied by connecting rails to ensure a flush, snap-on fit.

If we were to compare a Harbor Freight battery like a 20V Hercules pack to a comparable Ryobi offering like the ONE+ 18V pack, the problem would be readily apparent. Hercules batteries have a traditional comb-shaped panel on top, with several spaced divots housing the power transfer terminals. Another Harbor Freight brand, Bauer, has 20V batteries with a similar design, albeit with slightly differently-shaped divots and connecting rails. Ryobi ONE+ batteries, meanwhile, have a distinct stalk jutting up out of the top of the pack, which you can see the power terminals lining.

When a Ryobi ONE+ battery is connected to a ONE+ tool, that stalk goes directly inside the tool, its terminals lining up with the internal receiver. Because Hercules and Bauer batteries have flat panels, there's no way for the terminals within to actually reach the receiver in a Ryobi tool. Even if they could somehow, a Ryobi tool doesn't have compatible connecting rails, so a Hercules or Bauer battery would just fall right off.

Due to the differences in shape and connection, there is simply no way for any of Harbor Freight's power tool batteries to be fitted onto a Ryobi tool, at least on their own. That said, there are potential avenues for circumventing this physical limitation, created by those who want a little more interconnectivity from their power tools. Specifically, we're talking about power tool battery adapters, third-party products designed to be snapped onto the top of a battery from one brand and plugged into a tool from another brand. Using one of these would, in theory, allow you to connect one of Harbor Freight's batteries to a Ryobi tool. These adapters are typically sold on online store platforms like Amazon and eBay.

However, there are two big problems you need to be conscious of before you run out and buy a battery adapter. Firstly, all battery adapters are strictly one-to-one. You can't use one adapter for all batteries from Harbor Freight; you would specifically need a Bauer-to-Ryobi adapter or a Hercules-to-Ryobi adapter. Secondly, and more pressingly, using an adapter bypasses vital safety measures built into the batteries. All power tool batteries, including those sold at Harbor Freight, have an internal circuit board that regulates and optimizes electrical flow, communicating directly with a compatible tool. Using an adapter disables that safety system and forces power through. 

Unoptimized power delivery can result in either underwhelming performance from your Ryobi tool or a full-on overload that could end up burning out the motor. If either your Harbor Freight batteries or Ryobi tools are damaged as a result of using third-party battery adapters, neither brand will offer you service or replacements, as using unauthorized accessories is a violation of Ryobi warranties and Harbor Freight return policies.