Battery questions for fans

[fuumantroop[TK]]

Anyone had experiences using LiFePo4 rechargeable AA batteries in their TK bucket for the fans?

 

Im using a design like echos, using dual 12v blower fans. Currently, i have been using 2xAA and 1x9v to power them, but it just doesn't last that long, maybe 2-3 hours max. I have used 4xAAs before, but in the texas heat, it just doesnt blow as nice as the 2xAA and 1 9v(its like air conditioning and the fans i use arent loud at all at that voltage).

 

I spoke to a sales man at a local battery store. He recommended maybe using the LiFePo4 rechargeable AAs(rated at 3.3v). He does have those in stock, but no charger(kinda pointless right?). So im looking online to source either those, or even the UltraFire 3.7v AAs, and just mod the electronic config of my fan set up with 3 single AA connectors, or a 2xaa connector and a 1 aa connector.

 

 

I just dont know what to do! Any tech savy people out there that could help me?

[Sly11[Admin]]

I use the Ultrafire 3.6vlt rechargeable to run my Icomm as the internal battery went flat.

bought a $5 charger off ebay.

Make sure you get the Ultras with the built in protection circuit, as this allows a stable charge and discharge

Pretty sure the Ultrafire AA is 960mAh, so should run for hours.

 

See charger link below

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Edited March 31, 2022 by gmrhodes13
link removed no longer working

[rikrikrik]

Batteries as what you pay for, if you have a free source of batteries I would just use that as your battery type (ie while I was in the Australian army I could grab lithium AA and AAA batteries when ever I felt sneaky, I havnt seen anyone's helmet using the battery packs in RC cars, maybe that's because of weight, the next gen of RC helicopters batteries are getting lighter, and some are smaller, a RC store would have the Chargers, you would need to build a circuit no matter what kind of rechargeable batteries you used to deal with stopping the batteries going to a zero charge state (that kills your batterie )

[fuumantroop[TK]]

Gotcha. So it seems like my best option is to pick up some ultrafires and change my battery connector to a single AA.

 

Could i keep on of my 2xAA connectors hooked up and only swap out the other for a single AA hookup?

 

My power configuration would then be a 2xAA connected in series with a 1xAA connector. Is this okay to do?

[Tolo[TK]]

The batteries that last me the longest are the Panasonic from the Dollar Store Followed by Duracell. I last about 3-4 hours with Echos fan system.

 

 

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[Sly11[Admin]]

If you hook your batteries in series, you will change the voltage.

As I understand it , you are currently running 12volt fans, the less voltage you feed them, the slower they will run. If you feed them too much voltage, they will burn out quicker.

You can buy a triple holder for AAA batteries, so 3 x 3.6 volt = 10.8 volts, should run the fans well. The higher the capacity of the battery, meassured in mAh or Milli amp hours will determine your running time.

The higher the mAh, the longer the fans will run.

So look for the highest mAh, you can get in a compact size.

Generally it is the Lithium Ion batteries that will give you the highest at the smallest size.

 

 

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[fuumantroop[TK]]

Im not sure im following the math on that. if i were to switch to 2 3xAAA holders, that would equal 9v(6x1.5=9v).

 

From talking to another friend, he was recommending LiFePo4 rechargeable batteries due to the higher "safe" running temperature compared to the Li-Ion batteries.

 

When i run 4 AA, the fans only get 6v of power, therefore underpowering them by 6v. I can definitely tell the difference between the airflow there, or lack there of.

 

The fans i have have a db rating of 25dba at 6000 rpm and cfm of 5.84.

[netslave[501st]]

I think he was talking about using 3 Ultrafire (@3.6v each) AAA batteries. 

[fuumantroop[TK]]

That makes more sense. Do AAAs run out quicker than AAs though? I am a noob to electronics

[netslave[501st]]

Generally speaking, the smaller the battery, the faster it'll run out on the same drain. Like he said, you'll want to find a battery that has a very good milliamp per hour (mAh). Or just carry around extra batteries!

I usually carry WAY more battery than I need. Like, running fans or lights off of multiple D Cell batteries. Investigate different options if you really need a long run. Big battery packs, battery belts, easily accessible battery holders so you can change batteries mid troop, etc....

[Sly11[Admin]]

I think he was talking about using 3 Ultrafire (@3.6v each) AAA batteries.

Correct.

It is a single holder that carries the 3 batteries.

One positive and one negative connector.

If you used 3 standard recharge batteries (normally only 1.2 vlt each) you achieve 3.6 volt. This was my original work around for my Icomm as it requires 3.6 volt exactly. Then I moved to a single Ultra fire 3.6 volt and a single holder.

So back on point, if you use the holder that holds 3 batteries, you will have the 10.8 volt and a fan that runs far better than the 6 volt it currently is getting.

 

As too the battery sizes and heat, if you drain the battery at less than its voltage, it runs longer and will heat up less.

You can get small cells with high mAh ratings, but generally they get quite expensive due to the content of the cell and the manufacturing process.

 

I think the Ultrafires will work fine to run your set up and are relatively cheap for what you get.

Don't worry, as you research your knowledge on this will grow and you will experiment more.

Learn the basics of parallel and series for wiring up and the rest will make perfect sense.

 

 

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Edited May 13, 2015 by Sly11

[fuumantroop[TK]]

Okay so i pulled the trigger on a set of 8 Ultrafire Li-Ion AA 3.7v batteries. I plan on using 3 of these to power my 12v setup. It will total 11.1v. The 8 pack was cheap, and are rated at 2300 mAh, it will also give me 2 sets(1 as a backup, along with 2 extras).

 

It was impossible to source batteries with a good enough mAh rating locally for a decent price, so ebay it is.

 

The batteries and the charger should all be in my possesion by Thursday, so i should have time to get them charged up and ready for the biggest convention down here in Houston, Comicpalooza.

 

I originally would have liked to get LiFePo4 batteries, but good affordable ones all seem to come from China, and would not get to me until next month.

 

Tomorrow im going to pick up a single AA battery holder and get it installed into my bucket to prepare for the convention. Also have to try o finish mu DLT19 and get my tk trigger board ready to go(just need to find me an ethernet cable).