Help: taking cow on bus - inverter/alt questions

[Dapplecreek]

We will be transporting a lot of very good beef across the country in a small chest freezer. It pulls 860 watts and has a surprisingly low starting surge current.

My wife is very sensitive to heat, so I bought a freestanding portable air conditioner (5000 BTU) which also pulls about 860 watts.

My HF 2000W Inverter will power both of 'em at the same time from the 12v deep cycle battery I just bought. So far, so good.

But 860w continuous while driving plus another 860w intermittent means a whole lot of current at 12v (76-158a?).

My thought was to run wires up from the battery box to my deep cycle battery and inverter (short run and stout wire). We would let the alternator power the ac and the freezer while driving, and let the freezer 'coast' overnight. For comfort at night we would use fans and the deep cycle battery - and disconnect the deep cycle battery from the starting batteries while the bus was not running.

Question 1: does my 5.9 Cummins alternator pack enough punch to power the inverter and charge the other batteries?

Question 2: instead of powering both, should I cool the freezer with dry ice? I would be counting on the bus' proverbial air leaks to keep from asphyxiating while driving, and open windows and fans at night.

[Brad_SwiftFur]

200 amp alternators are fairly common on buses, but keep in mind that this includes lights, gauges, fans, engine electronics, and every other electrical load on the entire 12 volt system, so running such an inverter at full load is also going to tax the alternator to its limits - likely shortening its life span. It should be fine occasionally, but not for extended periods.


A 5K air conditioner might help keep you cool at night, but it'll never keep you cool on a hot day and definitely *NOT* while on the road. Bus (belt driven) A/C's have a BTU rating beginning in the 50K range and go up from there, and even the smaller ones are barely adequate. For any amount of driving, you'll want to reconsider this.

[Dapplecreek]

Originally Posted by Brad_SwiftFur

...a 5K air conditioner...[will] never keep you cool on a hot day and definitely *NOT* while on the road.

Hm.

The plan was to park my wife in front of the a/c rather than to attempt to cool the whole bus. Also, we're cooling only the front third, as we'll have a bulkhead and cargo in the back.

Would this work? Should I give up on the portable AC altogether and just use fans and wet washcloths to keep my wife alive? Or just admit my limitations and ship her out by plane instead of subjecting her to the heat?

Crossing the country on Rte 80 in August, in case you're curious. No, this isn't ideal, but my new job starts in September.

[Mark_In_MA]

I think it really depends on your wife and how much heat she wants/can deal with.

I can think of some possible solutions, but they might end up with 4 or 5 days of misery and heat. I can think of one that would work, but a plane ticket might be cheaper.

I don't have a problem with heat, but I don't like it - so I think I'd end up with that AC running 24/7 the whole trip. That's going to be a problem overnight. (I'm assuming you're planning to sleep in the bus, not at a hotel?)


As a possible solution, you could try one of these ice-bucket coolers. I'd re-fill with ice from any rest stop that sells bagged ice. I'm pretty sure any container with a foam liner would work.

https://lifehacker.com/make-a-small-...ket-1627528963



Personally, I'd get a trailer hitch installed, and buy a hitch rack and generator. Just run the freezer and the AC from the generator. You've got 2/3 of a bus keeping it separated at the back, so it should be quiet enough inside. Either keep the generator, or put it on Craigslist once you get to your destination. You might find that a plane ticket is cheaper.

[family wagon]

Also keep in mind alternators often aren't intended to produce their full capacity output at 100% duty cycle -- it could overheat. Without any data on a specific model, I'd hazard a guess at 50%-70% of capacity for continuous use.

The freezer should "coast" through the night easily. It'll help if you fill it as much as possible. If the good food doesn't take up all the space, fill the rest with milk jugs/soda bottles/whatever filled with water, or even just pre-made ice blocks. The idea is to displace the air and occupy the space with something with better thermal mass.

There's a lot of air exchange thorough a bus on the highway even if you don't feel it. That bulkhead 1/3 of the way back will help, but it's likely still too much cooling load. If you can make a smaller partition, a "tent", in the bus and air condition just that smaller space you'll have a better chance with that portable A/C. What's your target temperature?

In any case do a test run. You have all the pieces, so set up the air conditioner and go for a 30-60 minute drive in the heat of the day.

You're taking I-80 west from Virginia to.. where? I know I've read it before but I forgot.

[Dapplecreek]

Originally Posted by family wagon

...In any case do a test run. You have all the pieces, so set up the air conditioner and go for a 30-60 minute drive in the heat of the day.

Good suggestion! We'll do it!

Originally Posted by family wagon

You're taking I-80 west from Virginia to.. where? I know I've read it before but I forgot.

We're off to Idaho - we sent our daughter there for school... she met this BOY... fell in love... married him (that part's good)... had a baby... and we're ACROSS THE COUNTRY?!?!? Need to get out there and spoil that kid!

[BTW - the fellow is actually a great guy and a super father]

[family wagon]

Originally Posted by Dapplecreek

Need to get out there and spoil that kid!

That's the grandparent spirit! I guess you'll probably be on I-80 all the way into Salt Lake City, then north on I-15 into Spud Country. Give a shout if you need anything while in/near the Salt Lake area.

[Trail Fairy]

Just a tip for your wife if she hasn't tried one... those Cooling Towels or Snap Towels are really quite amazing and very refreshing... for hours! Machine washable, easy to use. We've gotten them at Walmart, Menards, etc.

[Booyah45828]

I see no issues with the chest freezer. Even a larger one would be okay. Start with the beef already frozen hard. Dry ice will help and shouldn't off gas too much. As other's have said, eliminate as much dead space in the freezer as you can with other frozen things.

Onto the air conditioning. I think you'll be pissing in the wind with a 5k btu ac on a moving bus. Even with her directly in front of it, any cool air that it creates won't amount to much.

I also think a short trial run would be a great idea, but I would think anybody who would label themselves as heat sensitive wouldn't be comfotable in this situation. Your wife will have to be the judge in the end.

Plane tickets are cheap compared to a week of misery.

[Dapplecreek]

Originally Posted by Booyah45828

...Plane tickets are cheap compared to a week of misery.

And it is important to keep my wife happy. At this point we'll try the drive, but may divert to an airport if it's intolerable. Her choice to play it this way.

Thanks, all!