Apu not warming coolant for the truck.

You can't run a block heater off of an APU unless you get a larger alternator on the APU. AND at that, it depends on how old the APU is, a lot of them came with 65 amp alternators.

You are going to be drawing 120 amps just for the heater, and giving the efficiency of any inverter, you will need to add another 20 to 30 amps onto that.

So you can try it, be prepared to replace the alternator, and have dead batteries.

 

Yes and no. An electric one you are correct. I have one that burns diesel and it only pulls around 80W and around 1 gallon per 10 hours to run the pumps and heat the coolant. if you can charge a smartphone you can run this heater for quite a while.

They also have coolant based fuel heaters and filter heatets that run off a single burner and pump in the same way and just burn more diesel and have slightly bigger pumps.

 

Sorry, I was talking about block heaters, not diesel coolant heaters.

These diesel coolant heaters, I have in many trucks. The startup current for the 8kw ones is about 16-18 amps, and running is less than 7 from what I recall.

 

I called Thermo King. The tech said it would probably work. He would not recommend it. Running the block heater, most likely, will run the inverter at its maximum capacity. This would shorten the lifespan of the inverter.

 

If you guys are talking about the Espar Hydronic d5wsc model heater that came standard on many Freightliners and Intl's as part of the Parksmart System from 2018-2023....

Please be advised. Due to tariffs and a model change, Espar is no longer importing that model. Mine blew up last winter, and Freightliner wanted 2800$ for the last one in Dallas in the system when I went to buy one in October. Ebay and Amazon don't have 'em.

If you need one, or want a spare, there's an RV dealer in Wisconsin that has brand new in the box models for $1550, but I don't know for how long. I bought mine there and he shipped it to me. Solid transaction.

I'm not affiliated, just only place in the USA I could find one. PM me for the website if needed.

 

Just got reading material on the new carriers and apparently theirs is set up to use the factory block heater, don’t know about TK,

 

Yea i know, but they are both types of block heater same as a pickup and a van are diffrent types of work vehicle. I was trying to make the point you are correct that electric heaters that go into the block and heat the coolant with electric current to an element do not work when plugged into an inverter off an APU. Too much power draw to be sustainable beyond at most a quick warmup. And even then that is a LOT of power draw and a high chance of burning stuff up.

However a diesel powered one can and is often the best choice With little/no modification to the APU or vehicle aside from mounting. Its also going to likely cost less then modding out an APU and getting a big enough inverter and alt/batterys to supply current.

A webesto block heater is around $1300 with maybe 2 to 3 hours labor to install. Often less. A 3kw inverter from a good brand a larger alt and the wireing and labor to install them are going to run pretty close to the same when its said and done and be at best janky as hell.

 

Nahh i use the webesto block heater. Its better then the espar for MY use case at least. And having used both is a far higher quality heater. I ended up trashing my espar for an arctic fox heater (no im not affilated either just a considince) on my last rig due to how unreliable that #### espar was. And only reason i didnt get another fox this time was my webesto came as part of the arctic package i got.

 

My Tripac Evolution with the arctic package on it kept the motor at 80+ over night when it was -15 out last week. Truck fired up like it was sitting inside all night. Probably helps that I also have Arctic Fox tank heaters and all of the coolant lines running from the engine back to the APU and tank heaters are wrapped in foam/foil insulation. Even the fuel line going in / out of the water separator is wrapped. The APU was running all night though to keep the engine warm with the Espar bunk heater going to keep me warm.