What Maintenance Do Truck APUs Need?

Installing an auxiliary power unit to your truck can end up saving you a significant amount of money each year. In fact in most cases they end up paying for themselves after only about twelve or thirteen months. After that all you see are savings in your pocket. That being said, there are still a lot of questions on the topic of APUs. Over the past few weeks we here at have attempted to answer these various questions in different articles. Today’s topic is what kind of maintenance do these APUs need?

We have to remember that the diesel APU is literally a small engine that you are sticking onto the outside of your truck. As we all know, engines need maintenance. The typical maintenance that a diesel APU needs are what you would expect: Regular oil changes, fuel filter changes, and other general preventive maintenance you would do for any other engine. Another point to mention is that California requires DPFs on diesel APUs as well as on the actual truck engine. So, if you are routinely trucking in California you can either opt to have the DPF added to your APU and end up having to pay more maintenance costs or just not run your APU at all while driving through California. The choice is yours, but just be aware that adding more options like a DPF will also result in more maintenance needs.

There is one key thing to remember though when selecting an APU and that is brand name. The brand or company that you go with will directly determine how often you are having to do maintenance. For example, there is one APU brand name out there that requires you to perform maintenance every one-hundred hours of use. While one-hundred hours of use sounds like a lot of time… in reality, it is not. Let us say that you are a long-haul driver and spending four or five nights a week on the road. This could mean that you are running your APU for eight, ten, or even twelve hours a day. Times that by the week and you are looking at around fifty-hours of run-time per week. So, in just two weeks your APU will need maintenance.

These one-hundred hour models can be a pain in the ass, but they are also one of the cheapest APU models out there. As you shop around for APUs you’ll find that some have five-hundred hour service windows, one-thousand, and even two-thousand. Obviously, the two-thousand hour service requirement is the best of the best. This could mean only having to perform maintenance once or twice a year. That is a hell of a difference when compared to once or twice a month! Just be prepared to have to pay a lot more for these premium models such as Thermo King TriPac or Carrier Comfort Pro.

Another point to make here when it comes to maintenance is the finding of parts. If you select an APU with a lesser known brand name then you could have the hardest time finding parts to repair the unit. One brand name that is notorious for this is Rigmaster. They are routinely cheaper then other APUs out there but finding parts for these APUs can be very difficult. On the opposite side of the spectrum if you look at APUs like Carrier or Thermo King you will find certified dealers all over the country that can not only provide parts but can service your APUs with locally trained experts. So, remember folks that a cheaper upfront cost can end up coming back to bite you later on down the road.

Up until now this article has focused on the maintenance requirements of diesel APUs, but I am sure as many of you know there are also electric APUs. Electric APUs have their upsides and downsides. The downsides are that they a limited power supply that is pulled from the stored energy on your truck’s batteries. Once the batteries are depleted you no longer have any power from your APU and it can take anywhere from four to eight hours of your truck’s engine on to charge the batteries back to full capacity. Along with the limited power supply you are also limited timewise. The longest and best performing electric APUs can only last around eleven hours and that is in ideal conditions. If you are in a very hot or cold climate then you could see that time limit shrink even more. These electric APUs are not the most ideal for long-haul drivers.

There are upsides to those electric systems though folks. The biggest is that they require very little maintenance. After all, these electric APUs are not engines. They do not need oil changes or filter swaps. The most you will have to do is routinely check the electrical connections to ensure everything is connected where it should and there are no frayed or damaged wires or harnesses. At some point during the electric APU’s life you will have to swap the batteries out for new… but besides that there is no other maintenance required. These electric systems are great for drivers who have to wait at a dock or port for hours on end or if you are a long-haul driver and may not need power for the whole night.


Overall though folks the maintenance needs on an auxiliary power unit can vary quite drastically as you can tell from reading above. You could be looking at maintenance every month or just once a year depending on the brand name you chose. You may not be able to find parts depending on the brand name. Or, if you went the electric route then you may not even need to worry about maintenance. Whatever APU you end up with be sure to take care of it and ensure it gets the care that is needed. These are expensive machines and I would hate to see unnecessary wear and tear due to lack of maintenance.

Thanks for reading,

Alec Johnson

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