Multifunctional Mini Ammeter D02A Review

Today I’ll be reviewing the Personal Electricity Calculator Wattmeter Voltage also known as Multifunctional Mini Ammeter D02A that is sold in bulk on for FOB (Freight on Board) price of $6.92-$10.46 USD per piece but I bought 1 unit locally for $23.3 USD ($25 USD with shipping) to measure the power consumption used by my devices. The device has several features and one it is to allow you to calculate the electricity (Watts) consumed by your electrical appliances such as monitor, speaker, fan, PC, microwave and washing machine in real-time. Below are the mini ammeter specifications:

Mini Ammeter Specifications

Quick Details

Place of Origin: Guangdong China (Mainland)
Brand Name: N/A
Model Number: D02A
Measuring Energy Range: 0~15A
Accuracy Class: 1%
Output Voltage: 90~280V
Operating Temperature: -10~60
Dimensions: 110*64*63mm
Plug version: EU, UK, US, AU, Italy, Swiss, Chinese

Packaging & Delivery

Packing Type: Blister
Product Size: 110*64*78mm (EU version) 110*64*63mm (other versions)
Blister size: 190*130*80 mm (EU version) 190*130*65mm (other versions)
Carton size: 60*39*69cm 120pcs/ctn for EU version, 140pcs/ctn for other versions
Delivery Detail: 2 weeks


Energy monitor measures volt, watt, kWh, $ and time; different versions for using in different countries.


  1. Measure real-time voltage of the power supply (90~150V AC or 160~280V AC);
  2. Measure real-time operation power of the appliances (0~3000W);
  3. Show the power consumption (0~9999kWh);
  4. Calculate the cost of energy according to the pre-set price of energy (0~$9999); price of energy can be pre-set to the local price by users;
  5. Two ways for calculating power consumption and power cost: electricity consumption and electricity cost in single operation period and accumulated electricity consumption and electricity cost in all operation periods; can be manually cleared to 0.
  6. Operation condition monitor: The indicator light will flicker when the real-time ratio of operation condition reaches its alarm point. Ratio of operation condition is the ratio between accumulated operation time per hour (running power is over preset standby power) and 1 hour. Alarm point for ratio of operation condition and standby power can be pre-set.
  7. Show the operation time of appliances (0~24h~9999d)
  8. Two ways for calculating operation time: time in single operation period and accumulated time in all operation periods; can be manually cleared into 0.


Voltage: 90~150V AC, 60Hz or 160~280V AC, 50Hz;
Peak load: 15A
Temperature: -10~60
Humidity: 10~95% RH



Optional versions

UK version: standard 3-pin UK plug
EU version: 2-pin German plug (French plug optional)
US version: standard US plug, earthed
AU version: standard AU plug, earthed
Swiss version: standard Swiss plug
Others: This model is easy for customization with any different plugs.

Multifunctional Mini Ammeter D02A Photo

Front of the Box
The dark blue sturdy cardbox has a transparent plastic in the center to see-through the monitoring device. However, mine is packed with the manual and soft cushion on top of it. Therefore it does not show the item but the front cover manual.

Opening Box Content
The box contains a user manual, soft padding foam (protects 3-pin metal plug), blister packing (shells item from shock-vibration) and measuring device. The manual is written in English.

Box Cardboard with Foam
The blister packing is the one shelling the device beneath and sides of it. It acts as a cushion to absorb shock and vibration. However, the cardboard they used is thin, flimsy and not high enough to accommodate the longest pin (Earth-pin), therefore, it has made some indentation on the bottom of the box.

Size of the Mini Ammeter
It’s pretty small, the width is approximately 1 cm shorter to a Samsung Galaxy S5 Smart Phone (6.4 cm vs 7.25 cm) and the height is 11cm.

Screen Backlight
Here are 3 photoshoot of the screen, 1 in dark with blue backlight, 1 in bright room with blue backlight, and 1 in bright room without blue backlight. It’s difficult to see the digits without the backlight unless you view it in a particular 30 or 90 degree angle. The buttons are similarly to mouse click but requires twice the effort to press it. For those who owns Phanteks Enthoo Pro desktop case, the power button is same as this button’s characteristic.

Cryptic Short Form Names
The top and bottom of the screen has double-letter which refers to some of the monitoring features provided by this device:

  • AV – Voltmeter (110V/240V)
  • EC – Electricity Consumption
  • PC – Power Cost
  • PW – Current power in Watts (ON this screen most of the time)
  • RT – Ratio (Alarms you if power consumption increases as the product ages)


Testing Multifunctional Mini Ammeter

I have tested several household items especially my desktop computer. Below are my benchmark settings and measurements:

  • [Desktop] CPU: Intel 3770K 4.2Ghz OC, GPU: MSI GTX 760 Twin Frozr 2GB, RAM: G.Skill Sniper 32GB, SSD: 1 x Crucial 120GB, HDD: 1 x Western Digital 1TB Green Caviar, Fan: Noctua 140mm Fan x 4 + 120mm Fan x 1, PSU: Rosewill Fortress 750W Platinum, CPU Cooler: Noctua NH-D14, MOBO: Gigabyte Z77X ATX.
  • [Monitor] Dell U2713HM with no additional speakers.
  • [Video Rendering] Sony Vegas Video rendering is tested with these settings (10 bit-encoding aka Hi10, 30 FPS, 1280×720 pixels, Slow Preset, Mode: Film).
  • [Gaming] Defense Grid version 1 with all settings at Highest Quality at 60FPS on 2560×1440 resolution.
  • [Speaker] 2.0 Speaker Multi-media Amplified Speaker System played at 40% volume, 50% Bass and 60% Treble.
Desktop Computer (Modes) Power Consumption (Watts)
Off (from Windows-7 shutdown) 3.2 ~ 3.6 W
Off (from Power Supply) 1.6 ~ 1.9 W
Idle 51.0 ~ 51.4 W
Watching Movie, Anime, TV shows 63.0 ~ 70.4 W
Gaming (Defense Grid 1 : Min, Avg, Max Watts) 139 W, 165 W, 220 W
Load (AIDA CPU Test) 87.5 ~ 88.1 W
Load (Sony Vegas Rendering with Intel HD4000) 102.4 ~ 106 W
Load (Sony Vegas Rendering with MSI GTX 760) 139.0 ~ 142 W
Dell U2713HM Monitor (Modes) Power Consumption (Watts)
Standby 0.9 W
White Screen (0% Brightness, 25% Contrast) 18.3 ~ 18.6 W
White Screen (0% Brightness, 50% Contrast) 18.9 ~ 19.1 W
White Screen (0% Brightness, 100% Contrast) 20.1 ~ 20.4 W
White Screen (100% Brightness, 25% Contrast) 45.9 ~ 46.1 W
Calibrated (46% Brightness, 75% Contrast) 24.8 W (Black) , 28.7 W (White)
Others (Modes) Power Consumption (Watts)
2.0 Speaker (Idle, Instrumental, Techno Loud) 3.5W , 4.7W, 7.0W
16 inch Stand Fan (Speed 1,2,3, Startup) 35.1W, 37.6W, 38.6W, 48W
Top-Loading Washing Machine 218W
Charging smart phone with micro-USB (Charging, Charged) 5.3 ~ 5.8W, 2.5W
Microwave (Standby, Light On, Heating) 4W, 24W, 140W
Old CRT TV 22″x17″ with Decoder (Idle, On) 14.4 ~ 17.2W, 84.3 ~ 111.4W
Refrigerator (National NR-B20ADM) 4.8W (Idle), 164 W (Cooling)

Final Thoughts and Conclusion

The multi-purpose ammeter doesn’t have an inbuilt battery. Having said that, it will lose all statistics of the logged power consumption when it is power supply is turned off but you do not need to worry whether the battery will run dead on you or battery-water leaks. The measuring instrument is light and small, which makes it easily fitted in a backpack for portability. The screen displays numbers similarly to a digital calculator. The screen also has LED blue background back-light which is bright when turned on within dark or light room. The back-light is auto-turned on when maneuvering through list of options presented in the device and auto-turns off approximately 15 seconds on idle.

The real-time Watt measurement fluctuates depending on the load of the electrical appliances. For instance, when measuring the Dell U2713HM monitor, I noticed that while playing a movie with dark scenes uses less watts compared to bright scenes. I was also quite surprised that even though desktop computer was turned off, it still consumes very little electricity, therefore its better to plug off or switch off from the main power supply! Another discovery that I found is as of 2014, desktop computers does not consume much wattage. Based on my desktop components configured in my Fractal Design chassis, the highest wattage it would consume for rendering videos would be around 110 W for pure CPU or 140 W for CPU+GPU processing. For gaming, power consumption hovers around 160W when playing games such as Defense Grid but once in awhile it will shoot up to approximately 220W depending on the intensity of the game. Total power consumption in my case was below 300W. In conclusion, you do not need to purchase a high-end PSU for your gaming PC as 80+ Bronze Certified 400-500W would be sufficient for most budget or mainstream rig along with added extra accessories (HDD, SSD, DVD-Bluray-Drive, Fan Controller, Water Pump, etc). Be aware that the power supply (PSU) should have sufficient amperage (A) along with the watts (W) supplied.

Currently, I used this device to check the total watts of the electrical appliances but you could use it to check whether the device uses more electricity after a period of time used. For instance, you have purchased a new item. You will need to identify the highest watt it fluctuates. Logged it into the ammeter, and set the percentage (e.g. 50% of 1 hour, so it checks every 30 minutes). If the watts used is higher than the logged, it will perform a blinking/flashing LED light to indicate the item uses much more electricity lets say after 3 months of continuous usage. Also, you can set in the power consumption cost per kWh (kilo watt per hour) so you can view the cost of it. But I find it not that useful since household power consumption increases by tier. For instance, 0-200kWh tier costs $1 per kWH, and the next 200-400 kWh tier costs $1.2 per kWh.


It’s an easy plug and view personal wattmeter which is similar to the Kill-A-Watt product. If you need to check the power consumption of an electrical appliance quickly, than this product is for you. Also, this product acts as an adapter so this gives you flexibility to plug in either 2 pin or 3 pin. However, I would recommend to look for other products if you need a device that has memory capabilities which will not lose its statistic when power down. This could happen if you accidentally turned off the power switch or your neighborhood has power failure. If you could find a wattmeter at cheaper price that does the basic feature, comment down here! I’ll report on my findings or issues encountered after using this product for a extended period of 3~6 months.

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2 thoughts on “Multifunctional Mini Ammeter D02A Review

  1. Hassan Sanim

    the information about gaming pc is so helpful for me thank you for this information

  2. ricardo vaz

    Boa tarde, qual a opção de pino do medidor que permite usar direto numa tomada no padrão brasileiro antigo. Já tive um D02A, e o uso de adaptador atrapalha muito. Obrigado