MacGregorSailors.com

O2 FROM WEST MARINE AS STATED 72 HOURS RUN TIME. Rechargeable also runs on D batteries, runs on 12 volt and 110 volt.

The O2cool fan is $59.99 at Amazon dot com. Looks like the same as WM and comes with all the power adapters. This is the one we have.



I'm not sure for the extra $ I'd buy this one again. The rechargeable batteries are nice, but not that necessary. This One is only $24.99 without the rechargeable option. You would need to buy an 12v adapter for it.

Both use 8 D cells but we plug it into a 12v receptacle. They don't mention the power consumption, but if it runs 72 hours on batteries, it can't be that much.

--Russ

I wouldn't count on the 72 hr run tine. The math isn't there. A typical alkaline D-cell has a capacity of about 12 amps. You have 8 of them, but since they are in series to achieve 12V, you still have 12 amps. Assuming that you can get all of the juice out of the batteries (You can't), 12 amps/72 hrs = .167 amp draw for the fan. The typical 4" 12V muffin fan draws .5 amps, so you can see that I am sceptical of a 10" fan that draws only 1/3 of that.

I'm not saying that it is not a good fan, but monitor your usage closely.

~Rich

We have one of these:
Endless Breeze 12v Fan

Plusses: Has three speeds. It only uses 1 amp, 1.5 amps, and 2.6 amps for the 3 speeds respectively.
Has 10 blades of 12" diameter so it moves a lot of air, 900CFM on high.
Stows under seat when not used, so no wires to run, holes to drill. I use it where I want, companionway or forward Just plug into 12v outlet.
Have run this all night and the amount of air it moves and noise level are great.

Minuses: Cheesy pivoting plastic feet break easily. No matter, I usually hang mine from bungee anyway.

Amperage, aka "amps" is a measure of instantaneous current. When it comes to batteries, "amps" are specified as Cold Cranking Amps, Marine Cranking Amps, i.e. the instantaneous current capability at a given temperature.

Current over a time period is expressed as amp-hours, and this is the rating used to express battery capacity. A common alkaline D cell is rated at 12000 milliamp-hours or 12 amp-hours, but it is unlikely to be able to produce a current of 12 amps in carbon-zinc or alkaline form.

Although most people are used to dealing with residential power over time (kilowatt-hours) they still confuse amps and amp-hours. Worse yet, they don't know that the amp-hour rating is based on a specified current draw, and will be higher at lower current draw and vice versa. This also isn't a linear relationship (see Peukert Effect). You can't reliably calculate a current draw (amps) from amp-hours divided by time unless that current draw is the same or close to that used to establish the amp-hour rating.

Now all this said, I probably wouldn't count on that fan getting 72 hours on a set of D batteries, but I wouldn't guarantee it wouldn't either.
--
Moe

The Endless Breeze fan is made by Fantastic Vent, a maker of top-notch RV fans with a stellar reputation. They've been known to support their product at no cost years out of warranty. We have two in our Airstream and love them. They move a tremendous amount of air, but also consume a tremendous amount of battery power relative to smaller fans.

--
Moe

Hamin' X wrote:I wouldn't count on the 72 hr run tine. The math isn't there. A typical alkaline D-cell has a capacity of about 12 amps. You have 8 of them, but since they are in series to achieve 12V, you still have 12 amps. Assuming that you can get all of the juice out of the batteries (You can't), 12 amps/72 hrs = .167 amp draw for the fan. The typical 4" 12V muffin fan draws .5 amps, so you can see that I am sceptical of a 10" fan that draws only 1/3 of that.

I'm not saying that it is not a good fan, but monitor your usage closely.

~Rich

Totally agree. Another of those silly claims that we know aren't true. The o2cool has BOTH rechargeable and D batteries. The Amazon reviewer claims to have gotten 9 hrs on the rechargeables. We plug it in to 12v power most of the time and have D cells as well. What I like about it is that it's so portable. Can be moved to the cockpit or in a tight spot while making mods.

The Endless Breeze seems like a quality unit with high output. I might be convinced to go with that one for 12v operation. We also had an oscillating 12v clip on fan. The thing was so noisy and didn't have a consistent sound so it kept us up all night.


--Russ

K-mart of all places has the O2 Cool on sale for $6.99. No AC adaptor, and uses 3 D cells, claims 52 hours continuous on low setting. Since they were so cheap I picked one up for the dinette table. Get 'em while there hot (or better it's hot)!

I just bought an O2 Cool fan, at WalMart, a couple of weeks ago. It was only advertised as being ac powered but I noticed that it used a wall wart type plug and the input connection on the side said 12Vdc. I bought it for $12-15(don't remember exactly) and took it home, dug through all my old cell phone car chargers and found one that fit, plugged it into the 12V accessory plug on the M, and va la! it worked. This thing is super light! and moves a decent amount of air. Looks almost identical to the one Duane Dunn posted in a pic. Only difference I see is that it appears that his has some sort of LED's on the front of it.

Jeff Posey
Madison, Alabama

Lake Guntersville, AL

jposey66 wrote:dug through all my old cell phone car chargers and found one that fit, plugged it into the 12V accessory plug on the M, and va la! it worked.

Yup! That's why I never throw away old cords and power bricks. And it's great when I finally get a chance like that to show my wife the value in keeping "all that old "junk" she want's me to get rid of.

RussMT wrote:

jposey66 wrote:dug through all my old cell phone car chargers and found one that fit, plugged it into the 12V accessory plug on the M, and va la! it worked.

Yup! That's why I never throw away old cords and power bricks. And it's great when I finally get a chance like that to show my wife the value in keeping "all that old "junk" she want's me to get rid of.

Russ, I assume she also knows that when you do get rid of something it never fails that within 2 weeks or so, you will need that which you just got rid of. Rob

SkiDeep2001 wrote:

RussMT wrote:

jposey66 wrote:dug through all my old cell phone car chargers and found one that fit, plugged it into the 12V accessory plug on the M, and va la! it worked.

Yup! That's why I never throw away old cords and power bricks. And it's great when I finally get a chance like that to show my wife the value in keeping "all that old "junk" she want's me to get rid of.

Russ, I assume she also knows that when you do get rid of something it never fails that within 2 weeks or so, you will need that which you just got rid of. Rob

So true. You've been there and felt that pain haven't you?

--Russ

RussMT wrote:

jposey66 wrote:dug through all my old cell phone car chargers and found one that fit, plugged it into the 12V accessory plug on the M, and va la! it worked.

Yup! That's why I never throw away old cords and power bricks. And it's great when I finally get a chance like that to show my wife the value in keeping "all that old "junk" she want's me to get rid of.

You can bet your aft that I pointed that out to the wife. She calls me a pack rat! It actually benefitted her this time, cause she is the one wanting the fan .

Posey

We have always used the 120vac Wal-Mart clamp on fans. They have a wide variety of them.
They draw so little current that a 150 watt inverter will power two of them , all night.

They are cheaper than the 12volt models and come in more variety , as well as move more air.