EL15 electronic load tested

(Published on 20/04/2026)

With ALIENTEK's ultra-compact EL15 electronic load, you can load batteries and power supplies up to 150 W, with a maximum voltage of 60 V and current of 12 A. The device can also perform automated tests.

Introducing the ALIENTEK EL15

Note

The EL15 is designed for testing rechargeable batteries, batteries and power supplies. To avoid having to list all these devices repeatedly, we refer to them in this article as the 'DUT', short for 'Device Under Test'.

The EL15 electronic load

You can clearly see just how small the EL15 is in the photo below, you can easily hold the device in your hand. And yet, this power sink, measuring just 106 mm x 65 mm x 48 mm, can load the DUT up to a maximum of 150 W. Thanks to two high-speed fans and a special heat sink, the internal temperature rises to only 75 °C at maximum load. This small device does not have a built-in power supply, you must power the EL15 from +5.0 Vdc via a USB-C connector on the right side. On the left side are two sturdy, illuminated 4 mm banana sockets for connecting the device to the DUT. There is also a male XT30 connector available if you wish to perform four-wire measurements (read on). The housing is made of sturdy black anodized aluminum. Four rubber feet are attached to the bottom, ensuring the device stands firmly on your workbench.

The EL15 is a device that fits comfortably in your hand.
(© 2026 Jos Verstraten)

The EL15 packaging

Great care has been taken with the packaging. The device comes in a sturdy cardboard box measuring 165 mm x 125 mm x 65 mm, securely packed in a thick protective styrofoam sleeve. A second cardboard box inside the packaging contains the cables and an XT30 connector.

The packaging of the EL15. (© 2026 Jos Verstraten)

What's Included with the EL15

In addition to the EL15 itself, the box contains:

       - A miniature 'Quick Start' guide.

       - A 120 cm high-quality USB-A to USB-C cable.

       - Two 60 cm long 4 mm banana to alligator clip cables.

       - A female XT30 connector.

If you want to perform four-wire measurements, you will need to solder the cable for measuring the battery voltage without power to this XT30 connector yourself.

The supplied components. (© 2026 Jos Verstraten)

The manufacturer

The EL15 is sold under the brand name ALIENTEK. This trade name is registered by 'Guangzhou Xingyi Electronic Technology Co., Ltd.’. This company was founded in 2012 and is based in Guangzhou, China. It specializes in the development and production of MCU development boards, Linux and FPGA boards, IoT solutions, measurement instruments (oscilloscopes, power supplies, logic analyzers), and education and training platforms. Their products are used at virtually all Chinese technical universities.

Suppliers and price

The EL15 is sold through the well-known online retailers such as Banggood and AliExpress for approximately € 70.00, including shipping.

The appearance of the EL15

In the montage photo below, we have put together the most important views of the EL15. The upper side is dominated by the 43 mm by 23 mm color display. Below the display are the controls, all of which are push buttons. The right side contains nothing but the USB-C power connector. On the left side, you’ll see the three connectors for connecting the EL15 to the DUT.

The frontal side consists almost entirely of a metal ventilation grille behind which the two fans rotate. The rear side features an identical ventilation grille, allowing air to flow freely through the interior of the device.

The views of the EL15. (© 2026 Jos Verstraten)

The EL15 Display

The 43 mm by 23 mm IPS LCD displays a wealth of information but remains easy to interpret thanks to its layout with colored frames. Status messages regarding the device’s operating mode appear in the top black frame. On the left, three large frames continuously display the DUT’s terminal voltage, the current drawn by the EL15 and the power consumption. A number of smaller frames on the right show various secondary information, such as the set current and the device’s internal temperature. 

It should be noted that the voltage in the lowest range is displayed with a resolution of up to 1/100 mV and the current up to 1/100 mA. This could have been two decimal places less, as those last digits are just jumping back and forth pointlessly and make the reading rather erratic.

The display provides a wealth of information. (© 2025 Alientek)

The highlights of the EL15

• 60 V, 12 A, or 150 W as maximum values.
• Two- and four-wire measurements, read on.
• Supports four different modes: CV, CC, CR, and CP. We’ll come back to that later.
• Extensive settings via various 'Settings' menus.
• Measures the internal resistance of the DUT.
• Displays a screen full of data about the DUT.
• Supports dynamic and automatic tests.
• Equipped with a 24 bit ADC, ensuring highly accurate measurements of voltages (0.05 %) and currents (0.025 %).
• Intelligent fan speed control.

EL15 Specifications

       - Voltage range: 0.5 V ~ 62.0 V

       - Current range: 0.1 A ~ 12.4 A

       - Power range: 0.5 W ~ 153 W

       - Temperature range: 50 °C ~ 90 °C

       - Voltage measurement accuracy: ±[0.05 % + 0.1 % of full scale] 

       - Current measurement accuracy: ±[0.025 % + 0.025 % of full scale]

       - Power measurement accuracy: ±[0.1 % + 0.025 % of full scale]

       - Resistance calculation accuracy: ±[0.1 % + 0.1 % of full scale]

       - Operating modes: CV, CC, CR, CP

       - Resolution settings: 1 mV ~ 1 mA

       - Display: 1.9-inch IPS LCD, 320 x 170 pixels

       - Power supply: 5 Vdc via USB-C

       - Supply current: 2 A max.

       - Dimensions: 106 mm x 65 mm x 48 mm

       - Weight: 275 g

Power supply for the EL15

The power source for the EL15 must be completely separate from the DUT being tested. Therefore, using a 5.0 Vdc power bank is the obvious choice.

The manual

In addition to the 'Quick Start' guide included with the unit, ALIENTEK has compiled a comprehensive 22-page PDF manual in English. You can browse through it on our account on the 'Internet Archive':

➡ EL15_Electronic_Load_Manual

The electronics inside the EL15

A housing that cannot be opened

You are used to seeing beautiful photos of the internals of the devices we test. That is not possible with the EL15. Without causing damage, we cannot get any further than removing the bottom of the housing. In the photo below, you can see that the interior consists mainly of a large and very special heat sink with numerous cooling fins.

The interior of the housing. (© 2026 Jos Verstraten)

Features of the ALIENTEK EL15

Two-wire versus four-wire

You can connect the DUT using two wires to the two 4 mm banana sockets. The device then measures the terminal voltage of the DUT at the banana sockets. This works well with an unloaded DUT, but if you test with significant discharge currents, the resistance of the connecting cables comes into play and the voltage at the banana sockets is lower than the terminal voltage of the DUT. You will then measure worse performance than the DUT actually has, such as a higher internal resistance.

To eliminate this measurement error, you can use the four-wire measurement method. The two banana sockets are then used exclusively to carry the current. You make a second small cable that you connect to the XT30 connector and to the terminals of the DUT. Now the EL15 measures the terminal voltage of the DUT directly and can therefore calculate the true internal resistance.

In EL15 terminology, the two-wire measurement is called 'Local' and the four-wire measurement is called 'Remote'.

The two measurement methods of the EL15. (© 2025 ALIENTEK)

The manual recommends twisting the two cables that connect to the XT30 connector. It is also absolutely essential to set the measurement method in the 'Settings' menu. To do this, select the 'Connection' option in the menu and choose either 'Local' or 'Remote'. Selecting the wrong option will result in significant measurement errors!

Selecting the measurement method. (© 2025 ALIENTEK)

Measurement mode

The EL15 supports four measurement modes:

• Constant Voltage (CV):
  The current drawn from the DUT is adjusted so that the terminal voltage of the DUT remains constant.
• Constant Current (CC):
  The EL15 always draws the set current from the DUT.
• Constant Resistance (CR):
  The EL15 behaves as a resistive load that obeys Ohm’s law. The ratio of U/I remains constant.
• Constant Power (CP):
  The product of U • I remains constant.

The figure below graphically illustrates these four measurement modes.

Graphical representation of the four measurement modes.
(© 2025 ALIENTEK, edit 2026 Jos Verstraten)

You can set the desired mode in the 'Basic Settings' menu. You can access this by selecting the 'Basic' option in the start menu. Then briefly press the button with the 'Settings' icon (top left). Of course, you can also set the desired values for voltage, current, resistance, or power in the 'Basic' option window.

Selecting the measurement mode. (© 2025 ALIENTEK)

Safety features

The EL15 is protected against: 

       - Overcurrent (OCP)

       - Overvoltage (OVP)

       - Undervoltage (UVP)

       - Overpower (OPP)

       - Reverse polarity

       - Over-temperature (OTP)

You can set and save the values for these parameters in the 'Setting' menu. If any of the values are exceeded, the test stops automatically and a warning window appears on the display.

The warning window. (© 2026 Jos Verstraten)

Test Functions

The EL15 allows you to test the DUT in no fewer than six ways:

• Capacity Test (CAP):
  After setting the measurement conditions, such as minimum terminal voltage and discharge current, the EL15 calculates the capacitance of the DUT.
• DC Internal Resistance (DCR):
  Two measurements of the DUT’s terminal voltage are performed using two different currents. Based on the voltage drop and the difference between the two currents, the EL15 calculates the DUT’s internal resistance.
• Dynamic Test (DT):
  You can set two test currents and two test times. The EL15 alternately applies both currents to the DUT for the set durations. You can also set the number of test cycles.
• Automatic Test (AUTO):
  After you have set the start current, end current, and step current, the EL15 automatically performs a step-by-step test from the start current to the end current, records important data such as no-load voltage, nominal voltage, and maximum power, and generates a test report.
• List Test (LIST):
  In this mode, you can set up to ten different discharge currents and times, which the EL15 will then automatically cycle through.
• Scan Test (SCAN):
  You can set a low current and a high current, as well as a rise time and a fall time. The EL15 then performs this test for a specified number of cycles, during which the current linearly decreases or increases from one value to the other during the fall and rise times.

Working with the EL15

The Controls

The figure below shows the control buttons on the front panel:

• 1:
  Opens the 'Settings' menu for the selected option from the start menu.
• 2:
  Goes back one step.
• 3:
  Opens the start menu.
• 4:
  Starts or stops the current sink of the EL15.
• ◄ and ►:
  Selects an option from a menu or a digit of the value to be set.
• ▼ and ▲:
  Selects an option from a submenu or increases or decreases the value of the selected digit.
• OK:
  Confirms a setting.

If you press button 4 for longer than one second, you activate the lock symbol on the display. The buttons are locked (except for 4), so you cannot accidentally change a setting. Pressing this button again for longer than one second exits this option.

The controls. (© 2026 Jos Verstraten)

The 'Start' menu options

Pressing the button with the 'Home' symbol (top right) opens the 'Start' menu. It has five options:

       - Basic

       - Battery

       - Power

       - Advanced

       - Settings

Use the '◄' and '►' buttons to select an option and press 'OK' to confirm.

The five options in the 'Start' menu. (© 2026 Jos Verstraten)

The 'Settings' menu

This menu has no fewer than thirteen options:

• Screen OFF:
  Automatically turn off the display after 5 min, 10 min, 30 min, or never.
• Temperature:
  Display the internal temperature in °F or °C.
• Language:
  Interface language is English, Simplified Chinese, or Traditional Chinese.
• Buzzer:
  Buzzer volume.
• Backlight:
  Backlight brightness in ten levels.
• Connection:
  Two- or four-wire connection method (Local / External).
• OVP:
  Overvoltage protection from 0.5 V to 62 V.
• OCP:
  Overcurrent protection from 0.1 A to 12.5 A.
• OPP:
  Overpower protection from 0.5 W to 153 W.
• OTP:
  Overtemperature protection from +50 °C to +90 °C.
• Log On:
  Selects 'Mean', 'Basic', 'Battery', 'Power', or 'Advanced' as the startup function.
• Others:
  Factory reset, Debug mode, Enable Bluetooth.
• About:
  Displays hardware and software version numbers.

The 'Basic' Menu

This is the simplest function, allowing you to manually set a load condition for the DUT. The display shows the current terminal voltage, current, and power. To the right of these, you will see the timer, the internal temperature, and the set value for voltage, current, resistance, or power. You can indeed set the measurement mode to CV, CC, CR, or CP by pressing button '1' in the 'Basic Settings' menu.

The available setting ranges are:

       - CC mode: 0.001 ~ 12.0 A, in steps of 1 mA.

       - CV mode: 0.100 ~ 60.0 V, in steps of 1 mV.

       - CR mode: 0.1 ~ 7,500 Ω, in steps of 100 mΩ.

       - CP mode: 0.01 ~ 150 W, in steps of 10 mW.

The display in the 'Basic' option. (© 2025 ALIENTEK)

The 'Battery' menu

This option allows you to calculate the internal resistance (DCR) and capacitance (CAP) of the DUT. Pressing button '1' takes you to the 'Battery Settings' menu. In 'CAP' mode, you can set the timer, the cutoff voltage (100 mV ~ 60 V), and reset the counters. In 'DCR' mode, you can set the two current values (1 mA ~ 12 A) and their durations (1 s ~ 99 s). Based on these two currents and the two corresponding terminal voltages, the EL15 calculates the internal resistance of the DUT.

Calculating the internal resistance DCR. (© 2026 Jos Verstraten)

The 'Power' menu

This option allows you to configure the 'DT' and 'AUTO' test functions. To do so, follow the familiar procedure: press button '1' to open the 'Power Settings' menu. 

In the dynamic test function, you configure the two load currents and a separate interval for each current (0.1 ms ~ 99,999.9 s). You can set the number of cycles up to a maximum of 99,999.

In the automatic test function, you can configure four parameters:

       - Nominal current.

       - Start current.

       - Stop current.

       - Step current.

Configuring the two currents. (© 2026 Jos Verstraten)

The 'Advanced' menu

This menu allows you to configure and run the 'LIST' and 'SCAN' test functions. Its operation is largely identical to that of the 'Power' menu. In the 'SCAN' test function, you can set the rise and fall times between the two current values to values between 0.1 ms and 99,999.9 ms.

Testing the EL15

Accuracy of voltage measurements

According to the specs, the EL15 measures the terminal voltage of the DUT with an accuracy of ±[0.05 % + 0.1 % of full scale]. That’s better than a lot of budget multimeters! Naturally, that calls for a test. We connected our Fluke 8842A in parallel to the two banana sockets on the EL15. This means both devices are measuring the same voltage. A power supply was connected to the EL15 and set to various voltages between 5 V and 60 V.

The results are summarized in the table below. To calculate the percentage deviation, we set the Fluke’s measurements to 100 %. The average deviation over the seven measurements is only 0.0265 %, better than the specs promise.

Accuracy of the voltage measurements. (© 2026 Jos Verstraten)

Accuracy of the current measurements

This is even higher than that of the voltage measurements: ±[0.025 % + 0.025 % of full scale]. To verify this, we use our second precision multimeter, an ET3255 from EastTester, connected in series with the DUT. Our power supplies can only handle up to 5 A, so that is the limit of our measurements. Again, we calculate the average percentage error: 0.071 %. That is higher than the specs promise. However, we must note that the error of the ET3255 on the 10 A range is ±[0.2 % + 60]. So this measurement is not entirely by the book!

Accuracy of the current measurements. (© 2026 Jos Verstraten)

Stability of the sink current

We measure this by setting the sink current to 1.000 A and applying various voltages to the DUT. The ET3255 is again used as a reference. As shown in the table below, the current remains constant to three decimal places. We can therefore be very satisfied with this feature of the EL15 as well!

Constancy of the set current. (© 2026 Jos Verstraten)

The Android app

Not via Wi-Fi, but via Bluetooth

ALIENTEK has developed an app for the EL15 that communicates with the EL15 via Bluetooth. Strangely enough, this app cannot be found in the Google Play Store. You can download it from the manufacturer’s website:

➡ https://en.alientek.com/Product_Details/72.html

The app is called 'atk-xtool'. However, our two Android tablets refuse to accept this app: 'Cannot install app.' We are therefore unable to report on the capabilities of this app. From other reviews of the EL15, we gather that you shouldn’t expect too much from it. The general consensus is that the app is far from polished and still needs significant work. Below is a screenshot from one of these reviews, so you have an idea of what to expect. Note the mix of Chinese and English text!

A screenshot of the Android app.
(© 2025 STAHOK)

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EL15 electronic load