ZMR250 is probably the most popular mini quad frame, because of its affordable price and practical design. However it’s not the most trusted frame due to the variable quality, and the large amount of fake carbon fibre frames on the market.
FPVModel.com very recently released a high quality full carbon ZMR250 frame. They call it the “V2” because they made a few exciting changes to the design, including an awesome PDB.
And here is the detail build log.
ZMR250 V2 Unboxing
Just from appearance, you can tell right away the quality is better than the V1 frame you can find on ebay or Banggood. It includes top and bottom plates, an integrated PDB, 4 arms, some other bits and pieces. (I forgot to show the 8 stand-offs in the picture)
And here is how it looks after the assembly.
And with the LED on.
Whole frame weights 185g (take away the weight of Power plug). It might seem a bit heavy, But mind you, 190g includes power distribution, LEDs, UBEC and filter, enhanced arms and body plates. You really cannot just simply compare the weight with a naked frame.
Enhancement from Original ZMR250 Frame
So what’s better on the ZMR250 V2 compared to the V1 frame? To Summarize:
- Integrated PDB, with built-in LEDs
- Better Carbon fiber
- Thicker arms and plates
ZMR PDB – Power Distribution Board
PDB can make wiring so much cleaner. There are many PDB that are designed for the ZMR, sold separately. Some of them are so popular they go out of stock within hours.
One of the good example would be the Overcraft PDB, and interestingly, the PDB included in this frame looks like an early version of Overcraft PDB (allegedly revision batch 3 ).
- Can handle 100A current Max (25A per motor)
- ESC Integration: You can solder your ESC power and signal wires directly on the board.
- 3S and 4S compatible.
- Onboard 5V BEC: This board uses a voltage regulator (L13603). You can power your flight controller and radio receiver with that onboard BEC (e.g. if you are using OPTO ESC). Alternatively you can also power the FC/RX with the BEC on ESC, there are solder pads provided.
- Easy option for voltage regulator if you are running 4S, and it requires 12V for video transmitter and FPV camera.
- 3 power options for FPV camera and video transmitter: 5V, Main battery voltage, or regulator voltage (12V on 4S).
- MinimOSD integration, it can be soldered under the FC that saves room, also simplify cabling a lot.
- Optional Buzzer solder holes: Buzzer is not included, but there are holes for easy soldering. Very useful if you lost your quadcopter in tall grass and you want to find it, or you want to setup your profiles without looking at the LEDs of the FC.
And I wanted to make sure the 5V regulator is working correctly with 3S and 4S LiPo batteries. I got 5.08V output on 3S (on the left), and 5.09V on 4S (on the right). Seller told me the 5V regulator can supply max 1A current.
This PDB can really make wiring simple yet clean. However the soldering pads might be confusing to beginners, and there is no documentation at the moment. So I spent hours checking all the pads, and drew a connection diagram. Hopefully that helps you understand how the PDB works, and where to solder your components and wires.
Some have concerns over not having GND with ESC signal wire. I am pretty sure that wouldn’t be a problem as I have been running my quad without ESC signal GND connected to FC successfully for many flights. But of course I think they should provide GND pads as well for ESC signal.
There should be enough room between the FPV board camera and the camera solder pads.
However it could potentially get obstructed by the ESC power solder joints. So make sure when you solder your ESC, make the joint as flat and low as possible.
The LEDs are not super bright, but they are visible even in day light. White at the front and red at tail, it really helps your orientation when flying line of sight.
But I have been wondering how to switch off the LED. Again, lack of documentation! I found two soldering jumping at the bottom of the board, not sure if they are for turning off the LEDs. Need to confirm with seller first.
Update on LED (12/07/2015): Seller told me LED is not possible to turn off.
Arms thickness have been boosted to 4mm, compared to 3mm in the V1 frame. Each arm weights 13.7g. For other ZMR arms, check out the Thug arms review (enhanced arms for ZMR250).
Look at the carbon fibre quality difference as well.
The shape of the arms are identical to V1, as well as the motor mount screw holes. That means we still face the same problem when using 2204 size motors (M3 bolts), we will have to drill the hole bigger.
Top / Bottom Plates and other accessories
Both top and bottom plates are also thicker with 2mm thickness.
The new ZMR frame has a matte finish, while the old version always has the glossy shiny surface.
They have made the hole on the top plate bigger, which is normally used to fix the VTX antenna extension lead. Before that, we had to drill the hole bigger ourselves.
Bolts used for arms are longer, and the vibration damping balls seem to be higher quality.
If FPVModel is ever going to make a V3, I think it would be nice to have these improvement.
Wider Arm motor mounts to protect 2204 motors
Bigger motor mount screw holes for M3 botls
Better documentation of PDB and it’s components, such as
- how much current the PDB can handle (answer: 100A)
- what’s the max current draw for the 5V regulator (answer; 1A)
- how to turn off LED (answer: not possible)
Build in 12V voltage regulator, or sell this PDB as an option for those who run 4S. (ideally has built-in power filter as well for FPV gear)
Why not include a buzzer in the package? They are so cheap! And it’s a pain the user has to buy them separately.
Maybe consider selling the PDB alone as well, lots of people who has already got a ZMR250 would love to get the PDB, and not break the bank getting a whole frame.
Ground solder pad for ESC signal.
MinimOSD solder pins misaligned. It will still fit, but you need to tilt the video signal and ground pins by about 10 degrees.
Solder pads need to be cleaned with alcohol before shipping out, they don’t solder very well, maybe oil on the surface from factory.
So, would you choose the V2 frame over V1?
This new mini quad frame is priced at $59. The V1 frame can be found $20-$30 on the internet depends on where you are getting it from, but you have no guarantee whether your frame will be full carbon fibre. Many crap ZMR250 V1 frames are made of Fibre glass.
To be honest, I don’t see anything that i haven’t seen before on this frame. Frame design is exactly the same, they only thickened the arms and frame plates. PDB is extremely similar to the Overcraft PDB if not identical.
Regardless the lack of creativity, I still think it’s worth the extra $30 to get the ZMR250 V2, not only for the reassurance of good quality carbon fibre, but also the PDB.
Update from FPVModel (27/Aug/2015)
We have now made something change to the PDB. It features ESC pads on the top and bottom of the board. Traces and main power distribution have been routed in a manner to avoid running under the arms. Optional 12V regulator w/ built in LC filter is now available.
Besides, the misaligned of MinimOSD solder pins now solved. Also, the arms for fitting 2204/2206 motors are selectable.