Portable a/c power source?

Ok so this has been something I've been pondering about for awhile. Been looking into portable A/C unit for the truck for overnight fishing/camping expeditions and I'm trying to figure out the power source.
Was thinking about this unit. Ignore the circle around the "12v to 24v adapter"


But I ran it by @bmf4069 and through our conversation figuring out power out put/hours was getting kinda confusing.

my basic plan to just have it run over night for about 6-8hours.

Would a YellowTop Optima/inverter be sufficient? Or should I look into some sort of small camping generator? Maybe use a secondary battery as a charging source for the camping generator?

Somebody who's smarter than me please chime in

 

Yeah, I've been looking at the Optima D27f battery. It shows a reserve capacity @25A of 140 minutes, so I'm guessing it can run for about 2.5 hours before it drops to 10.5 volts. This thing pulls 240w so 20A @ 12v.

 

I'd be worried if you were running that off your cranking battery. Run the AC too long and you're in the bush with a truck that won't crank.

A 4D or 8D maintenance free battery in a marine box mounted in the bed, wired to the cranking battery with either a manual disconnect or a contactor to charge when the truck is running. That would be the safer bet.

 

100% you would need a lithium battery to get through the night. Lead acid/agm batteries realistically get about half of their capacity rating.

If you look at the ecoflow wave it will show you some ideas of time with different battery capacities.
https://us.ecoflow.com/products/wave-2-portable-air-conditioner
It shows that with a delta 2 it gets 7 hours of run time. I believe the delta 2 has 1kwh of capacity.

If you are looking for an all in 1 solution for the power, the delta 2 is on sale for $500 on Amazon and they are running their Prime Days sales right now

 

Yea, I'm not gonna try and run anything off the cranking battery if at all possible. But I'm trying to figure out efficient options

so far, the best possible option seems to be just getting ecoflow delta.

 

damn you posted right before me. Yea, that seems like the most logical option as of now.

 

You could go with a wave2 (cheaper on Amazon than what was in your post) and a delta 2 and call it a day.

Ecoflow (direct) is having their sale this month, its usually the same price on amazon.
https://www.reddit.com/r/Ecoflow_co...coflow_prime_day_sale_reddit_only_7_off_code/

I would keep an eye on slickdeals...for a little bit of time the delta 2 was $429 on Wednesday.

 

How do you plan to charge it?

 

Take it out of the truck and charge it.....?

 

I THINK these can be charged in the truck via cig lighter or whatever while your driving

 

Yea, there's a few options for charging. Solar, cig lighter, and plug in

for my uses, unless I'm doing a multiple day trip, it really would be used for single nights so yoinking the fucker out to charge would be in the plans for whatever I build to have it mounted in the truck.

 

I have an Anker Solix C1000 that has been great for me. Around the same price as the Delta. Another great value is the Pecron E1500lfp

 

Looks like a fun project. I agree with @Danimal86 - a lithium power supply is the way to go. Lead/acid batteries don't do well when discharged below 50% and live a very short life when doing so. Looking at solar setups in vehicles and buildings that use 12vdc storage, lead/acid battery setups need twice the storage capacity as lithiums for this reason. With lithiums, most use 18650 or 21700 cells for storage, which are nominally 3.7 volts, but charge at 4.2 volts and can be discharged to around 2.5v (though this is debatable; some say higher, some a little lower). Either way, you need to have some sort of battery protection built in for the lithiums as well or you risk killing them in the same fashion.

You could build your own lithium battery using 18650 cells to ouput a nominal 24volts, but most prebuilt 18650 packs are built around 12v or 20v arrangements those or more common than 24v systems. You would also need some sort of under/over voltage protection and charging management system. You can purchase those on eBay or Amazon or Digikey, but quality can be questionable. If you decided to build your own battery, you would need:

-18650 cells
-Cell cases, custom most likely by might be able to find a 6 cell arrangement
-soldering skills and buss bars
-battery short/undervoltage/overcurrent protection
-battery charging

How many 18650 cells would you need?

24v/4v per cell = 6 cells per row to get your 24v. But your nominal voltage of 3.7 volts per cell gets you 22.2v.

Assuming you buy quality cells rated at 20Amps or more, and rated at 3000mah you are looking at 66.6 watts per row at 22.2v, so to get you to 240 watts... 240/66.6 = 3.60 rows, so a 4 row x 6 cell battery.

Thats a 266.4 watt battery at 3.7volts, or 1.11 amp-hours.

If you want to run it 8 hours, you would need 240 watts x 8 hours = 1920 watt-hours.

Using the battery arrangement above, you would need 1920 watt-hours / 266.4 watts = 7.2 batteries as you constructed above.

8 batteries x 24 cells each = 192 cells. At $8 each that's $1538 in cells alone. If you can buy in bulk for $6 a cell, you are $1152 in cells. Plus circuitry, plus housing, plus time.

A homemade battery doesn't look too viable to me, so lets look at other options. The one I'm most familiar with and that is the most flexible if you are a tool guy, is the Milwaukee M18 Carryon power supply. It will supply 120v using four m18 batteries, so you will also need a AC/DC transformer such as found here:

$57 24V 300W IP67 Waterproof Outdoor Power Supply, AC 100-265V to DC 24 Volt LED Driver, Transformer,Adapter for LED Strip Light, 3D Printer, Computer Project, CCTV

https://www.amazon.com/Waterproof-Outdoor-100-265V-Transformer-Computer/dp/B092VSFJ2G?th=1

But it's self contained, you can use an M18 battery, you can use those batteries for any other tools, the batteries are robust and safe to carry in the vehicle, they don't offgass like a lead acid, they come with built in under voltage protection, and charging is as simple as plugging the unit back in to a wall outlet at home (or an inverter on the vehicle). The Carry On unit can also be used for power your fridge or other things at home in the event of power outage (mine kept our fridges and freezers cool during and outage) or camping. So it is useful in other places. Also, the power calculations are very easy to do.

Lets say you use some m18 12 AH batteries. They are rated for 216 watt hours, so four batteries (as required by the Carry On) supply 864 watt hours of power.

At 240 watts of power demand, a quartet of 12.0's would last 860/240 = 3.6 hours.

Two sets of m18 12.0's would last 7.2 hours, which is right in the 6-8 hour range you were looking for. This, of course, is assuming 100% load and 100% conversion efficiency. Neither of those are correct, but this should be the correct ballpark.

Price of entry for the milwaukee is steep, though. The Carryon Unit is $700, the batteries are $250 each, so $1700 to $2700 for two sets of batteries.

A third option would be something like a Jackery battery supply. Using the same AC/DC transformer, you would use it the same way as the Milwaukee Carryon, only you won't get addicted to Milwaukee power tools. The Jackery Explorer 2000 is rated at 2160 watt hours, but is only recommended to discharge to 20% if you want the cells to last the full 1000 charge cycles, so lets take the 80% discharge of 2160 watt hours and we get .8 x 2160 = 1728 watts.

1728 watts / 240 watts = the same 7.2 hours of run time with another 1.8 hours of reserve if you want to run the unit down to 0%. At $1900 it's cheaper than buying the two sets of m18 batteries an Carryon Unit, but less versatile (if that matters to you).

Those are just some ideas...

 

The EcoFlow Delta 2 is only rated at 1024 watt-hours of a capacity and suggested 80% max discharge. So 819 watts, or 3.4 hours or usage. (again, assuming 100% duty cycle). If the AC unit has an Eco mode, it usually doubles the run time by halving the duty cycle.

 

It’s possible to run AC on battery power, but it’s not practical.
Just some “back of a napkin” math here.
240 watts draw from the AC which is 240 watt hours x 8 hours of run-time. So you need 1920 watt hour capacity — that’s 2 kilowatts just to get through one night and the battery would be flat dead each morning.
If the plan is to plug it in for a couple hours during the day, know that the quick charge only gets the battery to 80%, so you in that case you need a battery with 2.5 kilowatts capacity.
I gets expensive fast.

 

Been in the shop instead of shitposting on the forum and I missed this thread.

This SOK battery is the tits and cheaper per Ah

You'll need a charging solution. A DC/DC charger and the wiring from the alternator will run you another ~$200. It works out to be around the same price as the eco flow products linked earlier, but its easily expandable and serviceable.

 

It’s nice the cells are individually replaceable

 

@daveaeasa has a pretty slick ML-ACR charing set-up. Maybe he can chime in. I think he might be out of town this week though.

 

A 2 kw inverter generator would probably be a better way to go. Honda and Yamaha, both are good choices, but Harbor Freight makes one that is less expensive and seems to get good reviews. It would run just about any convenience device you want, along with sensitive electronics as well.