![MT50 Control Panel](https://www.experimental-engineering.co.uk/wp-content/uploads/2017/08/IMG_20170816_184832-300x169.jpg)
Here’s the MT50 controller from EpEver, that interfaces with it’s Tracer MPPT solar charge controllers, and gives access to more programming options on the charge controllers, without the need for a laptop. The display is a large dot-matrix unit, with built in backlight. Above is the display on the default page, showing power information for the entire system.
![PCB Rear](https://www.experimental-engineering.co.uk/wp-content/uploads/2017/08/IMG_20170816_191818-300x169.jpg)
The rear plastic cover is held in place by 4 machine screws, which thread into brass inserts in the plastic frame – nice high quality touch on the design here, no cheap self tapping plastic screws. Both power & data arrive via an Ethernet cable, but the communication here is RS-485, and not compatible with Ethernet! The PCB is pretty sparse, with comms & power on the left, LCD connection in the centre, and the microcontroller on the right.
![RS-485 Transceiver](https://www.experimental-engineering.co.uk/wp-content/uploads/2017/08/IMG_20170816_191814-300x169.jpg)
On the left of the board is the RS0485 transceiver, and a small voltage regulator. There’s also a spot for a DC barrel jack, which isn’t included in this model for local power supply.
![STM32 Microcontroller](https://www.experimental-engineering.co.uk/wp-content/uploads/2017/08/IMG_20170816_191809-300x169.jpg)
The other side of the board holds the main microcontroller which communicates with the charge controller. This is a STM32F051K8 from ST Microelectronics. With a 48MHz ARM Cortex M0 core, and up to 64K of flash, this is a pretty powerful MCU that has very little to do in this application.
![PCB Front](https://www.experimental-engineering.co.uk/wp-content/uploads/2017/08/IMG_20170816_191625-300x169.jpg)
The front of the PCB has the ENIG contacts of the front panel buttons, and the LCD backlight assembly. There’s nothing else under the plastic backlight spreader either.
![LCD Rear](https://www.experimental-engineering.co.uk/wp-content/uploads/2017/08/IMG_20170816_191602-300x169.jpg)
The front case holds the LCD module in place with glue, and the rubber buttons are placed underneath, which is heat staked in place.
![LCD Model](https://www.experimental-engineering.co.uk/wp-content/uploads/2017/08/IMG_20170816_191612-300x169.jpg)
The LCD is a YC1420840CS6 from eCen in China. Couldn’t find much out about this specific LCD.