My plan to buy an auxiliary power unit (APU) has been put on hold. Fortunately, the mild weather at this time of year means that I wouldn’t have seen much benefit from having one anyway.
The reason I’ve put it on hold is the price; because of the disparity between the US and Canadian dollar the price has jumped a whopping $3,000.
However, that doesn’t mean it’s not happening, but I’m having to think outside the box a little.I mentioned to the salesman that I was considering the electric APU and he was not overly enthusiastic about them at first, because he wanted my purchase to be the right one for my operation. The electric APU has limitations; not unexpected really as it runs on batteries which only have a certain amount of power before they run out of juice. The diesel-powered versions will run for much longer as long as there’s a larger supply of fuel available.
The electric versions also don’t have an in-built engine heating feature, which is achieved by the diesel-powered ones by circulating coolant. Obviously the electric version doesn’t charge the vehicle batteries either; if it could do that it would be a perpetual motion machine and that has yet to be invented.My operation involves running back and forth across the Prairies, so I’m not going to need air-conditioning as much as I would if I ran to the southern states.
With a little bit of forward planning I’m convinced that an electric APU would more than meet my cooling requirements. If I get the cab nice and cool before I shut down the big engine for the day and use the cab curtains to keep the sun out, the draw on the electric system will be much less than flicking a switch and letting the machine do all the work. Heating will not be a huge issue either. I have a bunk heater which keeps me nice and toasty, but when temperatures drop there comes a point when it cannot put out enough heat.
That point is not too far away from the time when a diesel-powered APU alone is not enough and I would be running the big engine anyway, so again I think I could manage.
The thing that puts me off is the cold starting ability.
As I said earlier, there is no coolant circulation, so the engine will be cold, the batteries will be in reasonable shape, apart from the cold which reduces their effectiveness. But I have a good set of deep-cycle batteries and I could invest in one of those starter modules that claim to be able to provide enough cranking amps from batteries that are only holding six volts and in temperatures as low as -50 C. They’re not cheap, but you get what you pay for.
An independent diesel-powered engine block heater will solve the cold engine problem. They run off battery power too, but if it’s wired to draw from the electric APU then it should keep my truck batteries healthy enough to provide sufficient amps for easy starting and those block heaters get the engine up to normal operating temperature in a reasonably short space of time, so the load on the truck batteries will be minimized. Of course I could just hook up an extra set of batteries, fit a split charging system and MacGyver everything else to fit my needs.
There would inevitably be a cost savings in doing this, but I have another trick up my sleeve, thanks to the APU salesman. He had sold a number of electric APUs to a fleet that already had the diesel-powered versions. Now, as I’ve said there are limitations to the electric version and this did not please the drivers at the company involved. Their work led them to the hotter parts of the US and they were having to run the truck after five or six hours as the batteries were drained trying to keep the truck cool. The drivers, fed up with waking up in a red hot truck halfway through their 10-hour break did what anyone would do in that situation and just ran the truck all night. This led to the company removing the electric APUs and refitting the diesel-powered versions.
To me it means that there are a bunch of nearly new electric APUs sitting in the corner of a shop somewhere. The salesman is trying to get a hold of one of them for me and although prices have yet to be discussed, I’m sure there will be a significant savings involved for me. It will also help the original purchaser of the electric APUs as they will make a little bit of money back (hopefully very little) and the salesman is looking after his existing customer and getting me the best deal possible – that’s not a story we hear often anymore.
I’m optimistic that this could actually work out in my favour. Apart from replacing batteries and maybe topping up refrigerant levels every few years, I will have zero running costs. I will have to buy an engine heater and possibly the starting module and I’m going to speak to my dealer to see if there’s any way I can get the factory system that fires up the engine when the batteries get low, fitted to my truck.
Such a system does exist and I’m thinking that I could have that in conjunction with the electric APU, engine block heater and starting module and have a system equal to a diesel-powered APU for a fraction of the cost. Time will tell.
A fourth generation trucker and trucking journalist, Mark Lee uses his 25 years of transcontinental trucking in Europe, Asia, North Africa and now North America to provide an alternative view of life on the road.