CAT 18V to Milwaukee 18V Battery Adapter
$51.00
Skip to product information
CAT 18V to Milwaukee 18V Battery Adapter
$51.00
Taxes included.
Free Shipping to Canada, USA and Australia! No minimum.
Use your CAT 18V batteries on Milwaukee M18 cordless tools, without buying into a second battery platform. Both platforms are rated 18V, so torque and speed on the Milwaukee M18 tool stay where they should be. Built with a durable injection-molded ABS housing and pure copper contacts for steady current delivery. Your existing batteries do more work, and there is no second ecosystem to buy into.
Specifications
- SKU
- PTA-CAT18-MIL18
- Fits this battery
- CAT 18V (Lithium-Ion)
- Battery voltage
- 18V
- Runs these tools
- Milwaukee M18 (Lithium-Ion)
- Tool voltage
- 18V
- Housing
- ABS (Injected)
- Terminals
- Copper
- Current rating
- 40A continuous (80A peak at 18VDC for up to 2 seconds)
- Internal wiring
- 5 mm²
- Weight
- 114 g (4.0 oz / 0.25 lb)
- Colour
- Black
- Operating humidity
- 5–95% RH
- Operating temperature
- -10 °C to 50 °C (14 °F to 122 °F)
- USB port
- No
- What's in the box
- Battery adapter
- Warranty
- 12 months after the date of deliveryMore details
Why choose this adapter
- Your CAT 18V battery and Milwaukee M18 tools run at the same voltage, so the adapter changes the fitting rather than converting anything.
- 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.
CAT 18V and Milwaukee M18 compatibility
It works in one direction only: CAT batteries powering Milwaukee tools. For the opposite pairing, see adapters that run on Milwaukee M18 batteries.
Compatibility can vary with the exact battery and tool model. Before ordering, confirm that your battery belongs to the CAT 18V platform and that your tool takes Milwaukee M18 batteries.
Important charging and safety information
This adapter is for powering cordless tools and nothing else. It cannot charge CAT or Milwaukee 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 CAT 18V battery.
How it works
-
1. Use the battery you own
Any compatible CAT 18V battery you already have.
-
2. Slide on the adapter
It goes where the original Milwaukee M18 battery sits.
-
3. Click in and work
No tools, no wiring, no modifications.
CAT 18V to Milwaukee M18 — Common Questions
Will my Milwaukee M18 tool run as long on a CAT 18V battery?
Runtime comes from the battery, not the adapter — a 5.0Ah CAT 18V 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 CAT 18V battery or my Milwaukee M18 tool?
Used with undamaged, compatible equipment it is not expected to. CAT 18V batteries are lithium-ion with a protection circuit built into the battery, and it keeps working through the adapter — it stays in the battery and never moves into the adapter. Stop when the tool slows noticeably rather than running the battery flat, and stop using the adapter if it becomes unusually hot or the contacts look damaged.
Can I charge through the adapter?
No, and it should never be attempted. The adapter carries power one way only, out to the Milwaukee M18 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 CAT 18V battery off the adapter and charge it on its own charger.
Does it work with third-party CAT 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 Milwaukee M18 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 Milwaukee M18 tool?
114 g (4.0 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.