All the gear for a 12v fan- bucket A.C.

[quadzool]

I'm making this: https://www.youtube.com/watch?v=HxSLbpAwibg, and he's using a 12v fan with a 15w, 1a solar panel. I want it for my van at night, so can I use a 12v, 12Ah deep cycle battery, with a cheap regulator, to get maybe 4 hours after the sun goes down? I'm going as inexpensive as possible, and I'm completely new to this, so please be patient.

[SunEagle]

Hello quadzool and welcome to Solar Panel Talk

That looks like a nice little project but unfortunately a 15watt 1amp solar panel will not be able to recharge any battery that will power that fan in a day.

Find the fan wattage and multiply that by 4 hours. That gets you close to your daily watt hour usage. Then you can size your 12volt battery. What ever amount of watt hours you calculate multiply that by 4 or 5 (which equates to 25 to 20% discharge). Then take that number of watt hours and divide by 12v. That will get you the battery Ah rating.

That 12v 12Ah battery can yield 144 watt hours using 100%. If you use more than 25% or 36 watt hours you will shorten the life of the battery. Your panel wattage (and charging amps) need to be sized to put back more watt hours then you take out due to losses.

So start at the beginning and find out how many watthours that fan will use daily.

[quadzool]

Using this, and Sunking's advice, below, I'm going with a 12v 18Ah battery- it's only $35 from Amazon- and forgoing the solar panel in lieu of charging the battery with my van. The space is just the inside of the van, so I'm thinking a .5A fan I found online will be enough. If this rig doesn't work, I'll upscale, and always find a use for whatever I bought, I've got enough projects going on. Thanks for the info.

[Mike90250]

I don't have a lot of bandwidth, so I think this is a simple swamp cooler, water spray + fan = cold humid air. This only works in dry areas, like deserts. More than 40% humidity
and it is just a fan. Evaporating water is cool. A 15W panel is not very much power
First, what power does the fan consume ? Is there a water spray pump : how much power does it consume?
Say the fan is 20 w and the pump is 10w. For every hour you run this, 30 watt hours (wh) is consumed
Panels produce about 80% of their nameplate, in perfect alignment conditions, so expect less than 12w from the panel. Solar hours are 10am - 3 pm summertime, at the best, so you can only harvest 11w per hour (x 5 hours) 55wh
Batteries need about 120% of what was consumed, to be recharged, 100W output needs 120W to recharge

30w x 4 hours = 120wh consumed
55Wh harvested in 5 hours
No, the load cannot run for 4 hours and be able to recharge the battery fully. You would need smaller, moire efficient fan and pump, or larger solar panel.

[LETitROLL]

I'm making this: https://www.youtube.com/watch?v=HxSLbpAwibg, and he's using a 12v fan with a 15w, 1a solar panel. I want it for my van at night, so can I use a 12v, 12Ah deep cycle battery, with a cheap regulator, to get maybe 4 hours after the sun goes down? I'm going as inexpensive as possible, and I'm completely new to this, so please be patient.

If will work okay if you keep the fan under 7w, a 15-20W panel, and 12-15ah battery would work as long as you stay down in that very low draw power range for the fan (under 7w).I saw one that looked similar to the one in your video that was only 4.5w. The cost and success of the project hinge on your power needs, so keeping the fan wattage low will make it possible, the lower watt fans will not move as much air, but that can have a side benefit of making your ice last longer and not having to add ice every 2 hours. They do work a bit in certain conditions, as long as your expectations are not too high and you build it correctly and have availability for plenty of ice (preferably block type), i think you would be okay.

[SunEagle]

If will work okay if you keep the fan under 7w, a 15-20W panel, and 12-15ah battery would work as long as you stay down in that very low draw power range for the fan (under 7w).I saw one that looked similar to the one in your video that was only 4.5w. The cost and success of the project hinge on your power needs, so keeping the fan wattage low will make it possible, the lower watt fans will not move as much air, but that can have a side benefit of making your ice last longer and not having to add ice every 2 hours. They do work a bit in certain conditions, as long as your expectations are not too high and you build it correctly and have availability for plenty of ice (preferably block type), i think you would be okay.

What I am curious about is which is more cost effective.

Using a small high efficient Air Conditioner for 4 hours or running that bucket cooler and running a freezer to make enough ice to run that bucket cooler for four hours?

[ButchDeal]

If the freezer is inside the house moving heat from the water to the room, and the bucket cooler moving the heat from the room back to the water.....

[quadzool]

You have a good point there, but I don't have a freezer, or a place to put one. In short, I don't have a place. Plus, if this works, given I'm in FL, I may be able to make and sell some, with either AC, or DC run fans.

[ButchDeal]

Well the point is you have to put a gallon of ice in it to get it to do any cooling. If you don't have a freezer then i suppose you would be purchasing the ice, which means it would be some pretty expensive hour of cool air

[Sunking]

Will never work.

What will work is just buying a good deep cycle AGM battery, say 12 volts @ 75 AH, and a electronic battery Isolator. Run the van engine 5 -10 minutes every other day to recharge. You have no need for soar, and it would not work even if you tried. My way will save you big bucks and will work.

[quadzool]

OK, I'll research this. As I drive at least 10 minutes every day, this would be as environmentally friendly as using a solar panel. More so, since I'm not buying and using as much stuff.

[LETitROLL]

What I am curious about is which is more cost effective.

Using a small high efficient Air Conditioner for 4 hours or running that bucket cooler and running a freezer to make enough ice to run that bucket cooler for four hours?

I think one of these bucket coolers should only be run if no other reasonable options exist, out camping, etc. and if a person is buying the ice and does not have a problem with the amount of cool they can get per dollar of ice, then okay. If a person is in a place where they can make the ice for it, then they usually have other options for a/c also (and should strongly consider them).

[SunEagle]

I think one of these bucket coolers should only be run if no other reasonable options exist, out camping, etc. and if a person is buying the ice and does not have a problem with the amount of cool they can get per dollar of ice, then okay. If a person is in a place where they can make the ice for it, then they usually have other options for a/c also (and should strongly consider them).

I agree. It does not make sense to have equipment to make ice but not to cool the area.

IMO more energy goes into making that ice then what is saved by using a bucket cooler. But if the ice is purchased for a reasonable low fee and the area is very dry and hot then a bucket cooler might do the job and save the person some money.

[quadzool]

OK, we'll make this simple. I'm living in my van, I have nowhere to make ice, and a real home-style A.C. unit is unreasonable. I'm seeking alternatives for the upcoming hot nights, when the van isn't running..

[SunEagle]

Oh I understand your need for this cooling unit. And it may very well do the trick to keep your van cool and I hope it works out for you.

I just wanted others that read this thread and might be thinking this is a low expense way to cool a room to think twice because it may be more expensive to cool an area this way then through traditional cooling equipment.

[Sunking]

Oh I understand your need for this cooling unit. And it may very well do the trick to keep your van cool and I hope it works out for you.

I just wanted others that read this thread and might be thinking this is a low expense way to cool a room to think twice because it may be more expensive to cool an area this way then through traditional cooling equipment.

Well let's see. A large bag of ice cost what? $3/10 lbs sounds about right. Commercial AC power around 12 cents/Kwh national average. So for $3 of electricity works out to about 25 Kwh.

An inefficient 1-ton Window Shaker you find in any Trailer Trash Park uses roughly 1100 watts and it takes roughly 22.7 hours to burn through 25 Kwh or $3 worth of electricity..

So which is a better deal?

45,400 pounds of ice for $3

or

10 pounds of ice for $3.

Any dang fool can figure that one out unless they are looking through Green Mafia sun glasses or educated in USA public schools living in a trailer park. .

[ButchDeal]

But But But, I saw it on pinterest it must be more efficient to use this bucket rig, the parts only cost a few dollars

[Sunking]

You must be educated in the USA.

[SunEagle]

Well let's see. A large bag of ice cost what? $3/10 lbs sounds about right. Commercial AC power around 12 cents/Kwh national average. So for $3 of electricity works out to about 25 Kwh.

An inefficient 1-ton Window Shaker you find in any Trailer Trash Park uses roughly 1100 watts and it takes roughly 22.7 hours to burn through 25 Kwh or $3 worth of electricity..

So which is a better deal?

45,400 pounds of ice for $3

or

10 pounds of ice for $3.

Any dang fool can figure that one out unless they are looking through Green Mafia sun glasses or educated in USA public schools living in a trailer park. .

All true. It would be impossible to say that it is cheaper to buy ice and cool off a small room using a bucket cooler instead of using even a quality window shaker plugged into the grid. I agree with your totally.

But in this case the OP is trying to cool his van which probably would be hard to mount a window shaker or any type of ac unit that plugs into an outlet unless he was in an RV park with full utilities. So while it still isn't cheap to buy ice and use that bucket the OP may not have the money or the chance to purchase an AC unit.

But for anyone else thinking the bucket cooler is a cheap way to go, Think Again. As you have pointed out you will be spending a lot more money in the long run.

[ButchDeal]

well you might get even cheaper cooling without the fan, solar, battery, or even bucket. just freeze 10 milk jugs of water and place in the van..... done.

[quadzool]

Well, this whole thing certainly took an interesting turn, but I'm going ahead with the project, because I really want to know now if a) it works like I hope it will, and 2) I can market any, if it's as easy to build as I assume it will be. Thanks for all the postings.

[LETitROLL]

It will work for sure, how well is the question, all the variables will dictate that, and if it is a success or not. Your van already has a battery and charger, so if you keep the fan wattage low you can save a pile of money just using those in the beginning until you see how you like it. If you stay around 7w or less on the fan your stock van battery should be fine for 4 hours and charge it back up in 10min the next day, no reason to have solar panel and extra battery at all unless your load gets bigger, or you cannot run the van to charge back up the next day. Getting the bucket A/C to work is the easy part, trying to run it long term from solar will get much more expensive and complicated.

[quadzool]

Yes, that's basically what I'm doing, but I also have a battery/electrical problem that hasn't yet been identified, so I have to use an extra battery instead of the van's. At least until that problem's resolved.