DL24 - An Affordable DC Active Load

                                DL24

$56 for a complete DC load.  But, the real selling point (and what makes this version more attractive than some slightly less expensive versions) is that it provides a USB serial and both SSP and low energy Bluetooth serial interfaces.  The manufacturer provides a link that you can use to download both an Android smartphone app (Bluetooth LE) and a Windows 10 PC application that can employ either the USB serial or Bluetooth SSP serial ports. (see eBay or Banggood for more information)

Sadly, the applications that you download are marginally better than nothing.  They duplicate some of the functionality of the built-in LCD screen and some of the manual switch control functions.  So, you can use these for very basic data viewing (though the UI defaults on startup to Chinese and when switched to English retains a few Chinese alphabetic elements).  In addition, only the basic Constant Current (CC) function is available in the applications.  Other functions, Constant Voltage (CV), Constant Resistance (CR), and Constant Power (CP) cannot be accessed.

There is a very important function that these applications do not provide.  The main reason to use a PC or smartphone application is to log data.  If a projected test executes for an extended time a user cannot be expected to open Notepad or Excel to record results.  I want the application to be able to archive this data to the computer for subsequent use.

October 20, 2022:  I have compiled a separate application, without automatic port identification, for Windows 7.  The required files are in the download, as well as a couple of small changes to the Windows 10 version. Read the Notes.txt file in the Windows7 zip archive.

The PC application that is provided by the manufaturer is not satisfactory (an understatement), so I wrote one that has the following feature list.  The full description of the application design and operation is included in the download.

• Manual operation with more control than is provided by the manufacturer's application.
• Automatic Active Load connection status.
• Log data to CSV files or TSV file.
• Built-in: Maximum Power Point (MPP - solar cell performance validation), Voltage Regulation (power supply validation), Battery Discharge Test (with estimated ESR), and
• Progammability to customize load profiles to simulate a variety of real-life loads and tests, including limited transient load testing (see the application design description)

  Note, the DL24 is powered by 12V via a standard barrel jack connector.  The ground connection used at the power jack is common to the load input ground connectors.  One might choose to power the DL24 using a common switched-mode “wall wart” supply.  Unfortunately, these commonly available supplies connect ground to the AC power mains neutral.  Thus, a substantial difference in ground potentials may exist.

  • Use only an isolated 12V supply (transformer based is cheapest; my junk bin had several) if the load is to be used to test any device that itself is not isolated from the AC power mains.  Otherwise, either the DL24 or the DUT may be damaged.

Download the full Windows 10 setup program and application details here.  This download includes a version for Windows 7.

Download version for Windows 10/11 that includes a serial communications watchdog function, enhanced data logging, and battery discarge testing down to 0.1V.