Bauer 20V to Hercules 20V Battery Adapter (with BMS, Vacuum Pump Compatible)

Use your Bauer 20V batteries on Hercules 20V cordless tools, without buying into a second battery platform. Power passes straight through: Bauer 20V and Hercules 20V share the same 20V rating. The molded ABS housing keeps it light and hard-wearing, and pure copper contacts keep current delivery steady. A practical way to extend the value of the Bauer 20V batteries you already have. It also carries battery protection electronics (BMS) inside.

Specifications

• SKU PTA-BAU20-HER20
• Fits this battery Bauer 20V (Lithium-Ion) from Harbor Freight
• Battery voltage 20V
• Runs these tools Hercules 20V (Lithium-Ion) from Harbor Freight
• Tool voltage 20V
• Housing ABS (Injected)
• Terminals Copper
• Current rating 40A continuous (80A peak at 18VDC for up to 2 seconds)720 Watt continuous at 18V nominal
• Internal wiring 5 mm²
• Weight 134 g (4.7 oz / 0.3 lb)
• Colour Yellow, Black
• Operating humidity 5–95% RH
• Operating temperature -10 °C to 50 °C (14 °F to 122 °F)
• USB port No
• Built-in BMS protection Yes
• What's in the box Battery adapter
• Warranty 12 months after the date of delivery
• Revision Revision 01 (released on October 12, 2025)

Why choose this adapter

• Your Bauer 20V battery and Hercules 20V tools run at the same voltage, so the adapter changes the fitting rather than converting anything.
• A Battery Management System inside the adapter cuts power before the battery is drained too far — protection your battery may not have on its own.
• Injection-moulded ABS, not 3D printed — no layer lines to split under load.
• Solid copper terminals, so less of the current is lost as heat.
• 5 mm² internal wiring, rated for 40A continuous with 80A peak at 18VDC for up to 2 seconds, so a high-draw tool is not held back by the adapter.
• Made for the Bauer 20V batteries sold at Harbor Freight, so the fit is the one you already own.
• Covered by a 12-month warranty from the day it arrives.

Bauer 20V and Hercules 20V compatibility

It works in one direction only: Bauer batteries powering Hercules tools. For the opposite pairing, see adapters that run on Hercules 20V batteries.

Compatibility can vary with the exact battery and tool model. Before ordering, confirm that your battery belongs to the Bauer 20V platform and that your tool takes Hercules 20V batteries.

Important charging and safety information

This adapter is for powering cordless tools and nothing else. It cannot charge Bauer or Hercules batteries and must never be connected to a charger of any kind. Always take the battery out of the adapter before charging, and charge it on the original charger made for your Bauer 20V battery.

Before you buy