Inexpensive 60V / 100A wattmeter / ammeter for modelers and not only

I have long wanted a wattmeter for myself to select screws formotors and measuring power consumption and current, stopped at this, found the cheapest seller. It was packed in polyethylene foam and a bag, an instruction was attached to the device (rather a passport) with a description of the possibilities and the limits of the measurements. Description from seller in English:
Color: Blue
Voltage: (0) V-4V-60V 0.01V (Resolution).
Current: 0-100 A peak 0.01A (Resolution).
Power: 0-6554 W 0.1W (Resolution).
Charge: 0-65 Ah 0.001Ah (Resolution).
Energy: 0-6554 wh 0.1 Wh (Resolution).
Measurement Update period: 400mS.
Signal Sampling Rate: sample / s.
Data Queue Sequence time: 2 seconds.
In Circuit Resistance: 0.001 Ohms.
Operation Current: 7 mA.
Auxiliary Power Voltage: 4.0V ~ 60V
Size: 84x50x20mm
Display Screen: 1602 STN LCD
On the left side there is an incomprehensible connector, possibly for connecting to a PC and plotting The device comes without connectors, I already soldered the XT-60 to my needs. When connected to a power source, it shows the voltage, very accurately, here is a comparison with a multimeter: And here are the readings of the wattmeter itself: No load indicates its own negligible power consumption and current.
Unscrew the 4 screws and remove the top cover: The device uses a standard display 1602without backlighting, the contrast and readability in daylight is normal, but in low light it gets noticeably worse, a little later I plan to change the display module to a backlit module, since they are of a standard size and are inexpensive. The device consists of two boards, which are fixed in the case with a piece of soft material such as rubber As a microcontroller, most likelyAtmega is used, but did not disassemble, for this you need to unsolder or bend the display module. Soft wires in silicone insulation with a cross section of 14 AWG (2.08 mm square) are soldered directly to the shunt, which is a pair of large smd resistors connected in parallel and located between the boards.
As a load, I’ll use this one-hundred-watt car bulb:
When the load is connected, the device showsconstantly in the right column current voltage and power, current current from the top left. (current readings are less than one hundred watts, probably due to the fact that the voltage in the vehicle’s on-board network is about 14 volts, the light bulb is designed for this + voltage dip of my battery) In the lower left corner sequentially with an interval of approximately 2 seconds, the readings for: Peak current (Ap),
Peak Power (Wp)
Minimum voltage (Vm)
Amp hours (Ah) and
Power Consumption in Watts (Wh) All peak readings are displayed when the load is disconnected.
In general, I liked the device, for smallmoney is very necessary for the modeler meter peak and current values, quite accurate. However, it can also be used for other purposes, for example, when charging a car battery, measure the capacity given to the battery.
Have a safe flight and have a good time with your electronic hobby!)