LiFePo4 battery pack instead of Lead Acid

For some reason it seems like you are getting upset that your idea is not receiving a good feedback.
When I stop for a 10 hrs break, I usually run a bunk heater, do some work on my computer or use my phone, all while my fridge runs on 3500 watt inverter.
I am absolutely sure that 95% of drivers do the same kind of thing and regular batteries are just fine for that. There is just no need for deep cycle batteries on a truck, unless you gonna be camping for few days, or have some special equipment like this
APU and generator alternative that works!

 

I do use a battery apu, I have 2 200ah renogy batteries, I ruled out lithium because of the horrid cold weather performance, they get cut in 1/2 in cold weather, and considering I spend 90% of my time in North Dakota and Minnesota and have a fairly good chance of getting caught in a storm and having to ride it out in my truck for up to a week in sub zero temps I couldn't chance going with them. If I was more serious about using my sleeper and epu all the time silica salt batteries are the way to go, they are as expensive as lithium but last as long and are more reliable in extreme cold temps, the draw back on them is the same as agm, they are heavy and take up more room, but would still work in my situation

 

Replacing an APU is the only reason for putting lithium iron phosphate batteries in a truck and I think its a good one. But this needs to be a well thought out unit with a good mini split .
I think these are on the way because all the parts already exist , its just a matter of time.
I have a buddy that has put together such a unit in his homemade camp trailer. I would link his youtube channel but he is such a sensitive person that I would worry about members here trolling him.
If you want I can send you a PM

 

There are a few things that need improvement before this can be a solid solution
One is that someone needs to come up with a good DC powered mini split , there is just too much loss and complication converting DC to AC. Ideally this would be a 48 volt unit and the whole system should be set up as 48 volts

The next is we need a really good DC to DC charger that knows how much power to safely pull from the alternator. Very few people are using alternator power to charge such a massive battery pack ( you will probably need at least 1200 amp hours at 12v) and it needs to spread that load over at least an 8 hour period

 

I dont think I would combine both systems. Keep the chassis batteries where they are and the LiFePO4 battery bank under the bunk where they are nice and cozy

 

Oh and you cant just rely on your BMS to manage the input, you definitely need a DC to DC