BMW N54 connected to a power supply while flashing DME control unit

Best Power Supply Units (PSU) For BMW Coding & Programming

Maintaining a modern vehicle in the workshop entails two acts that have a major impact on the battery: 

  • Diagnostic 
  • Programming (Flashing)

BMW recommends the expensive 100A+ Deutronic or GYS power supply units. Besides being a bit pricey, they are also harder to find in the US. So I’ve compiled the list of top 10 PSUs for BMW coding and programming. I’ve also categorized them according to jobs they are able to do and, of course, the price range. 

Let’s get started with the best. 

  1. GYSFlash 125.12 CNT [120A]

Good for:

  • Everything 
BMW part number:81 39 5 A5A FB0
Manufacturer:GYS – 252116 10

Where to buy it? At a BMW dealer or GYS USA.

  1. Deutronic DBL 1600 [105A]

BMW Part No.: 81 39 2 158 534

Where to buy it? At a BMW dealer or Deutronic America. 

  1. GYSFlash 100.12 HF [100A]

This is a powerful charger for BMW diagnostics, coding, and programming. While BMW recommends the GYSFlash 125.12 for use in BMW workshops, this one will get you covered for almost all BMW flash sessions. 

When I say almost, I think about some heavily equipped high-end models. I use the 100.12 on a daily basis and it has never let me down. 

One more advantage is Li-ion compatibility, so you can charge the F8x also.

Good for:

  • Flashing
  • Coding
  • Diagnostics
  • Charging 
  • ISTA+
  1. Clore Automotive PL6100 Flash [100A]
  1. GYSFlash 40.12 FV

The primary purpose of 40.12 FV is the power supply for the cars in the showroom.

Good for:

  • Flashing with E-Sys and WinKFP
  • Coding E, F, and G series 
  • Charging
  1. CTEK PRO25S

This is probably the best choice for DIYers. For less than $400 you’ll get a relatively powerful charger and power supply. 

The CTEK PRO25S is not designed for software updates, but it can be used as a power supply up to 25A. That means that it can provide a stable power supply as long as your BMW doesn’t need more than 25A while flashing. 

And if the battery is good, most 3 Series BMWs don’t need more than 15A. But the fully loaded 7 Series can draw more than 50A of current while restarting the ECUs during the flash. 

The downside is a missing voltage display so you’ll need to connect a multimeter or some other device to check the voltage. Also, the voltage can’t be adjusted. 

The great feature I like about this charger is its constant power supply even without connected clamps. This means that if you’ve disconnected the battery and closed the trunk, you’ll be able to supply the power under the hood terminals (GYSFlash and others can’t do this). 

It is also great for testing electric motors and other electrical equipment. 

Check the price on Amazon


While programming the car with ISTA and a “not-so-good” battery, the CTEK 25 can struggle to keep the voltage above 13V. When this happens the ISTA programming will be stopped and you’ll need to increase the voltage to continue and finish the programming session. 

I Had this happen a few times. The solution was to quickly connect another working car with jumper cables and increase the voltage to finish the flashing process. 

Keep in mind that while a WinKfp flash of a single module will take less than 10 minutes, the ISTA sessions can last for hours! 

Good for:

  • Flashing single modules with E-Sys and WinKFP (not all models) 
  • Not safe to flash iDrive head units 
  • Coding E, F, and G series
  • Charging 
  • Testing and power supply “on the bench”

Here’s the example of flashing the N54 MSD81 powered with CTEX MXS25. I’ve flashed these E9x DMEs many times without a single issue.

BMW E92 battery power supply by CTEK 25A while flashing DME with WinKfp
WinKfp MSD81 update in action
  1. Midtronics MSP-070

  1. Schumacher INC 700A 

DIY Guides

Converting Server PSU for BMW Flashing 


Georg Meier

BMW technician since 1996. I began my automotive journey in 1993 as an apprentice mechanic at Automag, the world's oldest BMW dealership in Munich. With years of experience and dedication, I garnered a wealth of knowledge about the intricacies of BMW and MINI vehicles. The love/hate relationship with the brand led me to found BIMMERIST where I share expertise and insights with fellow enthusiasts.

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