Ryobi 18V to Hercules 20V Battery Adapter
$50.00
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Ryobi 18V to Hercules 20V Battery Adapter
$50.00
Taxes included.
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Safety feature
Built-in BMS Protection
Integrated Battery Management System (BMS) helps prevent battery over-discharge and improves safety.
Use your Ryobi 18V ONE+ batteries on Hercules 20V cordless tools, without buying into a second battery platform. Built with a durable injection-molded ABS housing and pure copper contacts for steady current delivery. A practical way to extend the value of the Ryobi 18V ONE+ batteries you already have. It also carries battery protection electronics (BMS) inside.
Specifications
- SKU
- PTA-RYO18-HER20
- Fits this battery
- Ryobi 18V ONE+ (Lithium-Ion)
- Battery voltage
- 18V
- 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)
- Internal wiring
- 5 mm²
- Weight
- 158 g (5.6 oz / 0.35 lb)
- Colour
- Green, Yellow
- 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 deliveryMore details
Why choose this adapter
- 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.
- Covered by a 12-month warranty from the day it arrives.
Ryobi 18V ONE+ and Hercules 20V compatibility
It works in one direction only: Ryobi 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 Ryobi 18V ONE+ 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 Ryobi 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 Ryobi 18V ONE+ battery.
How it works
-
1. Use the battery you own
Any compatible Ryobi 18V ONE+ battery you already have.
-
2. Slide on the adapter
It goes where the original Hercules 20V battery sits.
-
3. Click in and work
No tools, no wiring, no modifications.
Ryobi 18V ONE+ to Hercules 20V — Common Questions
Will this fit my other Ryobi batteries?
Only Ryobi 18V ONE+ batteries. Ryobi also sells Ryobi 40V, and those use a different socket — same brand, different rail and contacts, so they need their own adapter. Compare the rail on your battery with the photos before ordering.
Will my Hercules 20V tool run as long on a Ryobi 18V ONE+ battery?
Runtime comes from the battery, not the adapter — a 5.0Ah Ryobi 18V ONE+ battery lasts roughly twice as long as a 2.5Ah one, exactly as it would on its own tool. The adapter’s copper terminals and heavy-gauge wiring are there to keep resistive loss low.
Could this damage my Ryobi 18V ONE+ battery or my Hercules 20V tool?
Used with undamaged, compatible equipment it is not expected to. This adapter has its own Battery Management System, which cuts power before the battery is drained too far, so it protects the battery even where the battery has no protection of its own. Stop using it if the adapter becomes unusually hot, the contacts look damaged, or the tool behaves oddly.
Can I charge through the adapter?
No, and it should never be attempted. The adapter carries power one way only, out to the Hercules 20V tool — there is no charging circuit inside it. Connecting it to a charger puts the battery, the charger and the adapter at risk. Always take the Ryobi 18V ONE+ battery off the adapter and charge it on its own charger.
My Hercules 20V gear came from Harbor Freight. Is that the same platform?
Yes — Harbor Freight is where Hercules 20V is sold, so a battery or tool bought there is the platform this adapter is built for. What matters is the socket, and Harbor Freight stock is the reference for it.
Does it work with third-party Ryobi batteries?
Usually. What matters is the socket, not the badge: if the battery slides on and locks the way an original does, the adapter takes it and the Hercules 20V tool runs. Aftermarket moulding does vary, so if yours looks unusual send us a photo and we will check before you order.
How much does it add to the Hercules 20V tool?
158 g (5.6 oz) and a short extension between battery and tool. You notice it overhead or in a tight cabinet; on a drill or driver held normally it disappears.