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48V Systems, Big Problems?

How to safely service and diagnose vehicles with 12V and 48V dual-voltage electrical systems

48V Systems, Big Problems?

48V Systems in Modern Cars

What SA workshops need to know to service them safely

Mild-hybrids using 48V systems are becoming common in South Africa. They improve fuel efficiency and support features like stop-start, coasting and e-boost without full hybrid complexity.

 

But they come with new service risks.

 

Key System Components:

  • 48V lithium-ion battery (extra, not a replacement)
  • Starter-generator motor (belt-driven)
  • DC/DC converter (charges the 12V battery)
  • High-voltage wiring (usually purple)

 

Common Service Issues:

  1. Safety first:
    Always follow the OEM shutdown procedure before working on the 48V system, some models need it deactivated via diagnostics.
  2. Crash shutdowns:
    Collisions can trigger auto-disconnects in the 48V system. Some vehicles (like Volvo XC60) log permanent faults, requiring battery replacement.
  3. Low battery charge:
    Short trips and cold starts drain the 48V battery. If charge drops, warnings appear. Idling may help but deeper faults need investigation.
  4. Wear and tear:
    Starter-generators place heavy strain on belts, pulleys and tensioners. These parts wear faster and must be installed correctly.
  5. Linked failures:
    A failed DC/DC converter may prevent 12V battery charging and one system failure can affect the other.

 

Get Ready for the New Standard

As more 48V-equipped vehicles hit South African roads, staying updated isn’t optional, it’s essential. Equip your team with the right tools, training and procedures now, so you can confidently service the next generation of vehicles tomorrow.