Fantastic Fan and Battery Drain

[Ratkity]

I've been lurking a while trying to read back as many pages as I can about battery drain, loads, charging, etc.

If I read correctly, the Fantastic Fan 4000r will pull 3 amps on its highest setting. If I have a 100AH deep cycle battery, my fan will run approx 33 hrs continuously. With that said, it's best to stop at 80% of battery which would be approx 33 hrs - 6.8 hrs ~ 26.2 hrs.

Thanks for the help!

Hugs,
Ratkity

[parnold]

Most threads I have read about batter consumption say not to drain the battery below 50%.

From what I hear of the fantastic fan, you won't need the high setting anyway.

[Ratkity]

LOL I ran it on high all weekend with shore power. It was HOT even in Hagerstown, MD. DC 'burbs hit 99F. I know some people don't like the noise, but I do. It drowned out some annoying bug zapper someone had 2 campers down.

Hugs,
Ratkity

[parnold]

I hear you on drowning out the noise, I have no trouble falling asleep to a constant vrrrrrrrrrrrrrrr but some random noises from a campground can wake me up 100 times.

[eamarquardt]

I've been lurking a while trying to read back as many pages as I can about battery drain, loads, charging, etc.

If I read correctly, the Fantastic Fan 4000r will pull 3 amps on its highest setting. If I have a 100AH deep cycle battery, my fan will run approx 33 hrs continuously. With that said, it's best to stop at 80% of battery which would be approx 33 hrs - 6.8 hrs ~ 26.2 hrs.

Thanks for the help!

Hugs,
Ratkity

All deep cycle batteries are not created equal. I'd recommend contacting the people that made your battery and finding out its exact specifications. I'd be surprised, unless you bought it at a specialty battery supply, that it is capable of repeated 80% depth of discharge. In addition, I'd suggest you also ask them what is the minimum voltage you should draw the battery down to.

Cheers,

Gus

[Ratkity]

Thanks Gus,

I'll check with the supplier. Is my math correct? Say it's 50% - so half of the max hrs would be 18ish hours run time.

Thanks!

Hugs,
Ratkity

[Shadow Catcher]

Or use computer case fans, and run for weeks.

[fromeo]

I've been lurking a while trying to read back as many pages as I can about battery drain, loads, charging, etc.

If I read correctly, the Fantastic Fan 4000r will pull 3 amps on its highest setting. If I have a 100AH deep cycle battery, my fan will run approx 33 hrs continuously. With that said, it's best to stop at 80% of battery which would be approx 33 hrs - 6.8 hrs ~ 26.2 hrs.

Thanks for the help!

Hugs,
Ratkity

Battery chemistry gets really (read: insanely) complicated.

When a battery is rated, say, 100Ah, that is commonly the "20 hour rating." If you put a 5A load on the battery, it will run for 20 hours.

Where things get complicated is that a 10A load will not run for 10 hours - it will run for less than that.

Along the same lines, if you put a 1A load on it, it will not run for 100 hours - it will run longer.

This behavior is described by "Peukert's Law" and a good article describing it is available here: http://www.smartgauge.co.uk/peukert2.html. You can plug the numbers into an equation and calculate actual capacities. There are some calculators available online as well.

So let's try an example. I have a Fantasic Fan "Create A Breeze" - on high, mine draws 1.84 A. If you had a fairly common wet cell deep cycle battery with a 100Ah (20 hour) rating you could expect that battery to power the 1.84A load for 134.97 hours.

Depth of discharge can be like discussing religion. Some people won't go below 70%, some 60%, others 50%, and I've seen some crazy flame wars start when discussing it. One thing is for sure - the shallower the discharge the more cycles the battery will survive. So depth of discharge becomes a balancing act..

Back to the example, if you were comfortable with a 50% depth of discharge, the Fan could be run for 67.285 hours.

This of course gets more complicated with multiple loads, but it is easy to make estimates with a spreadsheet.

- Frank

[eamarquardt]

Or use computer case fans, and run for weeks.

Right, some of them draw very little current.

50 amp hours/3 amps=17 hours assuming the battery is fully charged.

Batteries have their uses but a big part of the equation is putting the juice back in the battery. Tow vehicle, solar cells, gen set, shore power? Rule of thumb is you shouldn't charge the battery at more than 10% of its capacity. So with a 100 amp hour battery at 10 amps it will take 5 hours to recharge it. So do you run a gen set or drive for five hours? Solar can help a lot. Slowing the fan down with a PWM controller would buy you a lot if you don't need to run it on it's highest setting.

Think it through ahead of time, have a workable plan for both discharge and charging, and you'll be ahead of the game.

Cheers,

Gus

[48Rob]

So with a 100 amp hour battery at 10 amps it will take 5 hours to recharge it. So do you run a gen set or drive for five hours? Solar can help a lot. Slowing the fan down with a PWM controller would buy you a lot if you don't need to run it on it's highest setting.

Much to be said about having multiple batteries, so one doesn't need to worry about recharging until returning home from a trip...

Rob

[Ratkity]

Ok, so battery use is a balancing act. Did I read that right?

I have a brand new Napa 8240N:
Battery Voltage : 12
Wet or Dry : Wet
Battery Application : Marine
Battery BCI # : 24DCM
Battery CA @ 32 Degrees F : 685
Battery CCA @ 0 Degrees F : 550
Battery Height : 8 7/8"
Battery Length : 10 1/4"
Battery Load Test Amps : 275
Battery Posts Type : Top Mount
Battery Reserve Capacity : 140
Battery Weight : 45.4

On the top of the battery, the AH is 120. Is that different than the reserve capacity?


Hugs,
Ratkity

[Larry C]

Or use computer case fans, and run for weeks.

I have been observing your comments in several posts about using computer case fans for cooling a teardrop. I really like the idea if it works well. I would like to be able to use a motorcycle deep cycle battery or similar, to save weight. Can you tell me the actual amp draw of your set up?

Also have you ever compared your dual fan vent to the 4000 Fantastic fan? I am curious to know if you are moving as much air as the Fantastic?

Thanks,
Larry

[Ageless]

As for charging; a deep cycle takes a long time to recharge. I have a 6 amp charger and with the battery drained; it will pull a max of 4 amps.

[eamarquardt]

Much to be said about having multiple batteries, so one doesn't need to worry about recharging until returning home from a trip...

Rob

When I had a boat, I had three batteries. I used one and kept two in reserve for starting the engine as there is no push starting a 40 hp diesel connected to a propeller. I'd run the engine 20 minutes a day and went for a week at a time with no problem. Minimize load. We ran only a few lights at night, maybe a vcr/tv for a movie, the propane solenoid when cooking, fresh water pump, and saltwater washdown pump. Never ran a battery down.

Not enough info on your battery to tell exactly what it will do. Marine batteries are sometimes a compromise between a starting battery and deep cycle battery.

Trick to living on battery power is to keep the load light. If you have a hatch/vent in your roof you might consider:

http://www.yachtsofstuff.com/userPostin ... cexs=csol2

No power required.

Cheers,

Gus

[Shadow Catcher]

eamarquardt, the three stage chargers due to the electronics can bring a battery up to 90% charge with in a few hours e.g. the Progressive Dynamics charges in boost mode at 14.4 Volts till it gets to that 90% point then lowers it to 13.6 Volts and completes the charge.

Larry, . I just went out and measured .13A on low .22A on medium and .33A on high each. I used a couple of Antec three speed fans 120mm and on high they reportedly will move 100CFM each, (I did a lot of research on this to find CFM vs sound volume). We never used them on high at night.
The support bracket is reversible (the fans are not) to exhaust.
Our MM has an interior volume of 400CF, much larger than most conventional tears (any one else ever figure theirs out).

I believe the fan is the Antec 761345-75121-6 120mm Case Fan