How to install and code a 48 V starter generator

Although the development and production of electric cars is gaining momentum, as well as their popularity among customers, manufacturers of classic cars with internal combustion engines are not going to give up and are also constantly improving their cars. As one of the ways to reduce fuel consumption, and hence emissions, the introduction of Mild-hybrid systems is increasingly being used. Their main attribute that requires attention and sometimes repair – starter-generator 48 V, used to start the warmed engine, as well as to supply power to the high-voltage system of such cars. Let us tell you how we solve the problems that arise when these components need replacing.

Design and features of «soft» hybrid cars

Mild hybrids can be seen as something between a hybrid and a classic car, can – as an evolution of the «start-stop» system. Like other modern hybrid cars, they can be either petrol or diesel, as minimal changes to the design are needed to install the system. It is enough to connect a 48-volt starter-generator – with the help of a drive belt, like other attachments, to the already finished engine. The standard 12-volt starter &ndash starter remains in the vehicle – it starts the cold engine.

The 48V unit is only used for:

• starting a warmed up internal combustion engine;
• assistance of the remote control (e.g. when overtaking or climbing uphill);
• to supply power to powerful consumers (climate system, power steering, turbocharger).

There is no possibility to move only on electric power in «soft» hybrids, unlike others.

Mild hybrid starter-generator faults

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The devices are most commonly used on Volkswagen AG cars, primarily Audi brand. These are starter generators manufactured by Continental, water-cooled. Unfortunately, problems are also more common with them.

The top 3 faults look like this:

• failure of control boards due to too high charging current (typical for early variations of the units);
• overheating of power transistors caused by a malfunction of the cooling system, primarily the pump;
• falls of liquid (antifreeze) into the electronic elements of devices.

A fault in the starter-generator, the driver is usually notified by a yellow icon with the image of the battery on the dashboard. It is important not to ignore this signal, and be sure to contact a qualified workshop – for example, to us at STS for diagnosis and possibly repair. Whilst the vehicle does not lose the ability to continue driving in this case, charging of the high-voltage battery (48V) is usually stopped. The HVB can discharge to a critical state and shut down. The process of restoring its functionality will be labour intensive and expensive.

How we repair and install 48V starter generators

The manufacturer's default position is that starter generators are not repairable. Audi has announced recalls for them quite often in the past, but more often than not replaced them with new ones, free of charge under warranty. However, once the warranty expires, replacing them for money can seriously hit the budget.

Audi's default position is that starter generators are not repairable.

Purchasing a used starter-generator is often not only unable to remedy the situation, but can also be a source of new problems. Firstly, because the condition of a used unit may not be much better than a broken one. And secondly, just mechanically installing the alternator is not enough.

Obviously it is necessary to update the firmware to the latest versions and adapt it to the motor, namely: to prescribe the type of engine, cooling system. Therefore, independent installation is unlikely to succeed. It is possible that you will have to solve problems with the high-voltage battery. The STS workshop specialists can do all this quickly and expertly.

STS always has remanufactured starter generators for all popular Mild-hybrid cars. These units have already had both factory and in-service defects corrected. The latest firmware has already been installed in the control board. Instead of waiting for the repair to be completed, which can take several days, the customer can hand in their faulty unit and in return receive a fully reconditioned starter-generator perfectly matched to their vehicle.