Proper operation of the air conditioning system in hybrid and electric vehicles – more important than you think.

18 Aug 2022

The A/C system in “traditional” cars, i.e., powered by internal combustion engines, plays a basic role, namely, to ensure travel comfort by absorbing heat from the passenger compartment (sometimes it is also used in the heating system, depending on the manufacturer’s solutions). As a rule, its failure (depending on the fault) does not affect the correct operation of the engine, and thus, despite its failure, we have the option to continue driving (although, of course, in less comfortable conditions).

In the case of EVs (electric vehicles), the situation is quite different, as the A/C system is very often closely related to the cooling system of the high-voltage battery. A failure of the A/C system leads to the transition of the high voltage system to emergency mode (to reduce the battery power), and in some cases to an automatic shutdown of the system to protect the battery from overheating. The consequence of such a situation is no possibility to continue driving.

Therefore, it is even more important to regularly and properly service the A/C system.

Maintenance of the A/C system in hybrid and electric cars should be carried out with special care, in compliance with all rules related to the safety of working at high voltage.

In the case of maintenance of the A/C system in hybrid and electric cars, just following the safety procedures is not all, apart from them, it is necessary to remember an equally important aspect, namely the use of appropriate compressor oil.

The most popular oil in A/C systems is PAG oil (Poly Alkaline Glycol), with various viscosity classes (ISO46, ISO100, ISO150), while in the case of hybrid and EV cars we can encounter more often POE oil (Polyolester), which is characterized by the no-current conduction.

You should avoid mixing these oils, mixing POE oil with PAG oil leads to the loss of non-conductive properties of the POE oil, which creates a risk of electrical hazard (in the event of damage to the electrical insulation in the compressor, the current will flow through the compressor housing to the engine block and car body). In addition, these oils do not mix with each other, which disrupts the process of proper lubrication of the compressor, leading to its damage.

That is why it is so important to properly prepare the A/C service station, we always must be sure that the machine has a dedicated oil, and this oil has not been mixed with other oils.

Before the maintenance of the A/C system, it is necessary to verify the type of oil used by the manufacturer (this information can often be found on the rating plate or in the manufacturer’s technical specification).


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