Usually not, at least not without checking first. Most brands design their motors, battery boxes, receivers and remotes as one closed system, and connectors often differ between brands and even between product generations. Motors can often be mounted in another brand's model, but getting them to connect and work together is where problems start.
Why don't motors mix as easily as bricks?
Standard bricks only need to match a few measurements to connect. A power system is more complicated. For a motor to work, several parts have to agree with each other:
- The plug: the connector on the motor has to fit the port on the battery box or receiver.
- The power: the battery box has to supply the voltage and current the motor was designed for.
- The control: the receiver, remote or app has to "speak the same language" as the motor, especially for steering servos and speed control.
Two brands can match each other perfectly on brick size and still use completely different electronics. That's why our guide to brick compatibility across brands treats motors and power systems as a separate case. If you're new to building sets altogether, our beginner's guide to building block sets covers the basics first.
What parts make up a power system?
| Part | What it does | Works across brands? |
|---|---|---|
| Battery box | Holds batteries or a rechargeable cell and supplies power | Usually not |
| Receiver or hub | Takes signals from the remote or app and powers each motor | Usually not |
| Remote or app | Lets you drive, steer or operate functions | No, each is paired to its own receiver |
| Motors | Drive wheels, lifts, arms and other functions | Sometimes, if the plug and power match |
| Servo (steering) motor | Turns to set positions for steering | Rarely, as control signals differ |
| Cables and extensions | Connect parts that sit far apart in the model | Only within the same connector type |
How do LEGO's power systems work?
LEGO has used several electrical systems over the years. The two most builders come across are:
- Power Functions: LEGO's older system, which uses a square, stud-topped plug that stacks on top of other plugs.
- Powered Up: LEGO's newer system, which uses a smaller multi-pin plug and Bluetooth hubs controlled by a remote or app.
These two systems use different connectors and aren't directly compatible with each other. This matters because some other brands' and aftermarket electronics use plugs shaped like one of these LEGO connectors, while others use connectors of their own.
How do Mould King and CaDA power systems work?
Mould King makes many of its motorized sets with its own powered modules, which combine a battery box and receiver with a remote and, on some modules, app control. Its motorized range includes remote-controlled cranes, excavators and trucks as well as working engines and trains. See the full range of Mould King building sets.
CaDA also uses its own power system across its motorized and remote-control models. For example, its PRO power system pairs a rechargeable lithium battery and receiver with dedicated drive motors, a steering servo and a radio remote, and is designed for CaDA models that support it. Browse CaDA building sets to see which models come motorized.
Because each brand designs its electronics to work together, the simplest way to get reliable results is to use the power system the set was designed for.
Can you use one brand's motors in another brand's set?
There are two separate questions here.
- Will it fit physically? Often, yes. Motors are usually mounted with Technic-style pins and axles, which tend to fit across brands.
- Will it work electrically? Only if the plug fits, the battery box supplies the right power, and the controller can operate the motor properly.
In practice, builders who mix motors across brands often find that basic motors can be made to work with the right cable or adapter, while steering servos and app-controlled hubs are much less predictable. If you're not sure, it's best to ask the seller before buying.
What can go wrong when you mix power systems?
- The plug doesn't fit: the most common problem, and the easiest to spot.
- The motor doesn't respond properly: it may run only at full speed, or a steering servo may only turn fully left or right instead of smoothly.
- Too much or too little power: running a motor on a power source it wasn't designed for can make it underperform, overheat or damage the electronics.
- Harder support: if something stops working, it's harder to get help when parts from several systems are involved.
How can you motorize a static set?
If you'd like to add movement to a set you already own, start with the options designed for it:
- Check for a motorized version. Some sets are sold in both static and motorized versions, so the motorized one may be the easier choice.
- Look for the brand's own upgrade kit. Some brands offer power kits designed for specific models.
- Consider an add-on kit. General motor kits, like those in our power functions collection, can bring movement to your own builds, but check the connector type and how the motors will mount before you buy.
If you're still deciding what kind of set to buy, our guide to the difference between static, motorized and RC sets will help.
What should you check before buying a motorized set or motor kit?
| Check | Why it matters |
|---|---|
| Which power system it uses | Tells you which motors, remotes and apps will work with it |
| Connector type | Decides whether parts from other kits can plug in |
| Battery type | AA batteries or a rechargeable battery affects running cost and convenience |
| Whether batteries are included | So you can run it as soon as it's built |
| Remote or app control | Apps may need a compatible phone and a Bluetooth connection |
| Motorized or static version | Some sets come in both, so check which one you're buying |
For motorized ideas, take a look at our construction vehicle building sets, which include motorized cranes, excavators and trucks, or see our picks of the best motorized building sets. You can also get to know the brand behind many of them in our profile of Mould King.
FAQs
Can I use Mould King motors in a CaDA set?
Not directly in most cases. The two brands use their own power systems, so motors, battery boxes and remotes aren't designed to work together. It's best to use the system each set was designed for.
Are Power Functions and Powered Up compatible?
Not directly. LEGO's Power Functions and Powered Up systems use different connectors. Third-party adapter cables exist for some combinations, but control and features won't always carry over.
Do motorized sets come with batteries?
It depends on the set. Some include a rechargeable battery, while others need AA batteries that aren't included. Check the product details before you buy.
Can I add motors to a set that isn't motorized?
Sometimes. The easiest route is a motorized version of the same set or the brand's own upgrade kit, if one exists. General motor kits can also work in your own builds, as long as the connectors and mounting points fit.
Will using another brand's battery box damage my motors?
It can if the voltage or power doesn't match what the motors were designed for. If you're not sure, don't mix them, and ask the seller first.
Why does my steering only turn fully left or right?
This often happens when a steering servo is paired with a receiver from a different system that can't control its position smoothly. Using the servo and receiver from the same brand usually fixes it.
