12/24 volt AC ( air conditioning )

[dzl_]

12V (5K btu) model draws 370w on low (410 on medium, 485 on high)
24V (7K btu) model draws 360w on low (440 on medium, 540 on high)
They also have an 8K btu 12V model, and a 12K btu 24V model


A decent inverter has roughly 90% efficiency right(?), so when comparing wattage with 110v units, remember to factor that in.




"Run time of up to 8-10 hours based on 4 Deep Cycle AGM Batteries and depending on ambient temperature, truck insulation and solar load."
Evaporator Inside Size: L 22" x W 12" x H 10,5"
Evaporator Weight approx. 62 lbs
Outside Single Fan Condenser 14 " tall x 20"wide x 4 1/2" thick
Warranty: 2 year Parts and 1 year Labor


[URL unfurl="true"]https://www.cruisencomfortusa.com/hd-series[/URL]

[cadillackid]

these look promising as it sounds like they use a true low voltage motor to run the compressor. vs converting the power all over the place...



there is definitely Loss in something like a Home minisplit being run off of 12 VDC.. considering in a minisplit you have


12VDC-->120VAC-->[A/C Unit here]-->120VDC--->INVERTER(3 phase vari volt and freq)


lots of power conversion goes on inside a mini split.. a true DC system wit ha DC variable motor seems it could be more efficient in terms of power consumption...



installing multiple units allows you to maximize cooling only the space you are currently occupying.. if your solar makes extra power over usage and battery charging during the day you leave the unit or units run all day..


-Christopher

[jofred99]

Also the 48v option. Shows 980w max and 500w normal cooling. Because it is a heat pump, it is capable of providing heat (~722w). These are about $2k
https://www.hotspotenergy.com/DC-air-conditioner/


I'm interested in the 12/24v options also. Did you get any pricing info from this vendor?

[bubb, the real one]

High Blower Speed 38 nominal amps @ 12.8 Volts DC
Medium Blower Speed 32 nominal amps @ 12.8 Volts DC
Low Blower Speed (Whisper Mode) 29 nominal amps @ 12.8 Volts DC


agm and wet lead acid batteries can at max provide only about 10% of their rated capacity long term, this means a 100ah deep cycle battery can only be drained at 10 amps, with my personal Ac unit draining at this rate for only 15 minutes dropped the volts below 11v and shut down the unit.


38 amps, lets say 40 amp draw,


10% capacity means a 400ah battery bank
5% capacity means 800ah battery bank, I imagine this size battery bank will be pushed to its limit in an hour or two, the volts will probably drop, but as always ymmv

[dzl_]

Originally Posted by bubb, the real one

High Blower Speed 38 nominal amps @ 12.8 Volts DC
Medium Blower Speed 32 nominal amps @ 12.8 Volts DC
Low Blower Speed (Whisper Mode) 29 nominal amps @ 12.8 Volts DC


agm and wet lead acid batteries can at max provide only about 10% of their rated capacity long term, this means a 100ah deep cycle battery can only be drained at 10 amps, with my personal Ac unit draining at this rate for only 15 minutes dropped the volts below 11v and shut down the unit.


38 amps, lets say 40 amp draw,


10% capacity means a 400ah battery bank
5% capacity means 800ah battery bank, I imagine this size battery bank will be pushed to its limit in an hour or two, the volts will probably drop, but as always ymmv

Good points, but much more sensible than getting 4-800ah lead acid in my opinion would be to upgrade to Lithium. Most decent Lifepo4 batteries can handle a 1C (sometimes higher) discharge rate. 1C = 100% of your batters AH rating per hour.

[dzl_]

Originally Posted by jofred99

I'm interested in the 12/24v options also. Did you get any pricing info from this vendor?

I'm not positive, but I'm guessing upwards of $1000. They don't look cheap and look to be solid quality.

[brokedown]

Lithium cells are still coming down in price, but it's a tough sell when the cheapest LiFePo4 4S packs are still $450 per 100AH...

https://www.aliexpress.com/item/4000306076197.html are about as as good as you're going to get on new cells.

[john61ct]

Cheap is opposed to good, especially risky importing yourself.

[brokedown]

The units I posted have name brand cells in them. Review here:

https://www.youtube.com/watch?v=Di2o7an-WJw

[john61ct]

Running aircon off solar requires more panels than most have room for.

Remember you have to refill your battery bank and service all the other loads at the same time too.

Figure adding 1500+ Watts of panelage to what you otherwise need, for cooling even a tiny superbly insulated space.

And 100Ah of storage for every hour of timeshifting.

Yes can sometimes be done, but rarely practical.

Better to design around aircon off a little genset, then add LFP storage for some timeshifting

and then however much solar you can fit up top, to reduce gennie runtime.

Marginally greater efficiencies in the aircon system itself only helps a bit around the edges.

Best of all, you're mobile!

Move to where it's not so hot, just a 500' in altitude can make a huge difference.

And get your body acclimated, with excellent ventilation, and awnings cooking & living outdoors, will find you don't need much aircon at all.

[john61ct]

Originally Posted by brokedown

The units I posted have name brand cells in them. Review here:

Are you certain the vendor is trustworthy?

Counterfeits are common.

Even if genuine, used cells often sold as new.

Even if new, factory QA rejects are **very** often sold as if Grade A.

I bet if you contacted CALB directly you could find a way to buy from them directly.

Warrantees are useless if you have to pay for shipping back to China.

Be prepared to do thorough testing upon arrival, both for capacity and internal resistance.

[john61ct]

Will Prowse is a YouTuber, not actually an expert in DC electrics, much less LFP technology.

Great for noobs to learn 101-level stuff, but after dealing with him in various forums over the years, I would not follow his specific recommendations unless they were further supported / verified by members I trust more.

[brokedown]

Regardless of yotuber knowledge or not, my point is that even the cheapest possible name brand cells are multiple times the cost of lead. Maybe this trend helps drive down the price of "80%" used cells. LiFePo4 is great tech, don't get me wrong... Just expensive.

[john61ct]

Yes, absolutely, 5-7x more per usable Ah in the NA market.

Problem is in very high consumption use cases, carrying enough lead storage around gets prohibitively heavy and takes up too much space.

Plus lead requires getting back to 100% Full as quickly and frequently as possible for decent longevity, past say 4-5 years.

Which takes a minimum of 6-7 hours even without concurrent loads, no matter how big the genset.

Whereas LFP never needs to get to Full, can fully recharge in an hour or so in hot weather, and if cared for properly may well last decades.

Besides twice the energy density, and supporting much higher loads without dropping voltage.

[Jolly Roger bus 223]

so why not look into the cheaper pioneer brand of mini split with the 12v conversion already in the unit.
needs 120 for start up but runs 12v

[dzl_]

Originally Posted by Jolly Roger bus 223

so why not look into the cheaper pioneer brand of mini split with the 12v conversion already in the unit.
needs 120 for start up but runs 12v

Hadn't heard of that, sounds interesting. Do you have a link or the power specs?

[PNW_Steve]

Originally Posted by brokedown

Lithium cells are still coming down in price, but it's a tough sell when the cheapest LiFePo4 4S packs are still $450 per 100AH...

https://www.aliexpress.com/item/4000306076197.html are about as as good as you're going to get on new cells.

Not exactly my idea of cheap.

I get excited about affordable lithium batteries and BMS. I could replace my $1300 FLA bank with Chinese lithium batteries for around $3600.

I think that I will keep the FLA batteries.

[brokedown]

Cheap is relative.... Meaning it's cheap if you've got a rich relative funding you!

[dzl_]

Originally Posted by brokedown

Cheap is relative.... Meaning it's cheap if you've got a rich relative funding you!

Or if you are thinking about the longer term.

I wouldn't call lithium cheap by any stretch but when you actually make an apples to apples comparison (or as close as you can get) that accounts for depth of discharge, usable battery life, and whole system efficiency, I think lithium is at least cost competitive with lead acid.

Cost Comparison: Lead Acid vs LiFePO4 vs DIY LiFePO4 vs Tesla

Lead Acid vs LiFePO4

[john61ct]

Only if you actually do get the extra long lifespan.

That may not be "that difficult" but risks do exist.

At $1/Ah for Duracell / Deka GCs, the ROI payback minimum is at maybe 15 years.

Depends how much you invest in BMS charge sourced, new charge sources, alt / VR etc.