deals3-in-1 battery resizer – replace c or d batteries…

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At $5.99, this deal is not quite as cool as I thought when I Wooted it.

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@jnet9102: you have a few minutes, 5 or 10, to un-woot something you woot for. you un-woot by clicking the woot button again within the timeframe.

i'm glad i got your initial impulse woot, though ;-) i tried searching just now and only found one other place selling these. the shipping alone was $10, the item was $3 or $4.
this item would be good if you have a stash of all AA batteries, or only renewable AA batteries with a specialized charger or something. i dunno

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Quick correction, it's not just $4.99 to ship... it's $4.99 to ship PER ITEM. Now I know why they call themselves "daily steals". Order 10? It's $49.90 to ship them. Wow, that's just exceptionally low morals to run a business like that.

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Gives your batteries the size you always wanted. Instantly turns your AAA into large D cells.

Useful, but $6 is too much. Sometimes rechargeable batteries come with adapters as "bonus" or for a couple dollars more. I use the adapters (different brand) for a water timer that wants D cells.

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Considering that these cost more than 2 D batteries and considering that the typical capacity of an Alkaline AA battery is around 2900 mAh, while the typical capacity of an Alkaline D battery is around 12000 mAh, I think I'll pass.

The reason D batteries exist is because they have a higher capacity and need to be replaced less frequently. Does anyone really say with any great level of frequency "man, I wish I could use my AAs in my wireless doorbell because I love changing them monthly"

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I want to turn AA into D because D batteries are very expensive, but I have a Nerf gun that uses them. Those AA batteries are going to be dead by the next time I use the gun anyway, so what difference does it make if I have to recharge them?

That said, I need three of these, and refuse to pay $15 for shipping.

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I guess the patent didn't pan out on these. The side of the item says patent pending, and also has a non-existent website: www.cellmatebattery.com. A sign that will prevent me from trying these. I have some I got in an Eneloop package deal, but they don't work in flashlights that take C or D batteries since the back is open and doesn't make contact with the spring. Not sure if these have the same flaw, but not worth it. It's also hard to get a patent for existing products....

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In a pinch, you can use paper to wrap your AAs to the proper diameter. If you need to extend the size (aaa->aa) you can use AL foil.

Problem here is that the AA may not have the oompf needed for the bigger batteries (total amps out). a better "converter" would take up to three AA batteries to make the D cell. You might have to worry about internal discharge if you mix batteries though since you don't have diode blocking.

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You guys looking for adapters like this should go check out DealExtreme. I'd post my referral link, but I think that's kind of shady on a deals site like this. They have AAA to AA, AA to C, and AA to D adapters for a decent price and shipping is free (unless you opt for express shipping). If you buy a lot of a particular item, you can get bulk pricing (I think 3 or more of an item qualifies). The only problem is that they are in Hong Kong and it takes a while for things to arrive. On the plus side, by the time it arrives, you might have forgotten you ordered them and it's like getting a surprise in the mail that you weren't expecting.

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These don't hold a good charge in my extra large vibrator. Guess I'll have to go to Pep boys for a new battery.

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These are handy, good for emergencies too...but not for $5.99 EACH (shipped). You can regularly pick these kinds of things on Meritline.com..

Also: what @flippurr said.

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How much power does each battery have? How long can a AA battery power something requiring D?

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I mod Nerf guns, and these are great for converting the high-power AA's I use in my Barricades into D's for my Stampede. Sure, shipping's not cheap, but the still end up being cheaper than I normally find them, and DEFIANTLY cheaper than replacing my D's as often as I have to.

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@demonicgman:

I think roughly 1/4 the life (alittle less). As mentioned above AA batteries typically hold 2900 mAh (mili Amp Hours) or 2.9 Ah (Amp Hours). In otherwords the AA battery can produce 1 Amp of current (@ 1.5 Voltage DC) for 2.9 hours.

The D battery however as mentioned above has 12000 mAh, or 12 Ah. 12 Ah divided by 2.9 Ah (lets say 3 for sake of easy math-hense why the answer was really alittle less then 1/4 the life of a D battery) and you get that 1 AA battery is 1/4 that of a D Battery. They both produce the same power, but the D battery has a larger capacity (and is larger in size because of that).

By the way, something that draws 1 Ah of current @ 1.5 Volts consumes 1.5 Watts per hour. thats to say it is only drawing 1 Amp per hour. What if it were 2 Amps drawn then? Then the you'd have half the life since you are drawing current twice as fast.

Oh and if you power anything at 1 amp per hour @ 1.5 volts, youre device has a resistance of 1.5 ohms.

Ohms law!

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If I am not mistaken (its been awhile),

Ohms Law:
Volts times Amps = Watts
Volts/ Ohms= Amps
amps/ Ohms= Volts
Volts/ Amps= Ohms
Ah= Amp hours= # hours a charge can last at a discharge of 1 Amp per hour.
mAh= Amp hours divided by 1000, or mili amps.
Ohm= measurment of resistance
Amp= measurment of current
Volt= Measurment of Energy
Watt= Measurment of Power (amount of energy it takes to make something happen)

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I picked up a bunch of Eneloop AA to D converters on ebay for fairly cheap (a lot less than this - maybe $20 for 8, shipped).

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You can get (8) Soshine 2-AA to D adapters for $5.16 shipped from Asia: http://cgi.ebay.com/8-x-Battery-Adaptor-Converter-Case-AA-D-rechargeable-/260593024302 . They convert 2 AA cells to a D cell, for double the capacity of the typical 1-AA to D adapter that gets bundled with Sanyo Eneloop Costco packs and LaCrosse BC-9009 charger. I just received mine days ago after around 2 weeks of shipping from China. These are the same adapters that places like Meritline and DealExtreme sell for over $1 each. The plastic hinges on these adapters do break after years of use so it's nice to have spares (I only need 6).

I plan to use (2) of these 2-AA adapters with (4) rechargable NiMH AA cells in Woot 2-D Cree 3-Watt flashlights to get ~4 hours of bright light (instead of ~2 hours with (2) 1-AA adapters and (2) AA cells). This will give me reasonable battery life with easy-to-find-cheap NiMH AA instead of expensive alkaline D or NiMH D cells+charger.

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@bmseaton: They don't actually produce the same power, as D cell batteries have a higher maximum current rating than AA cells. So at the same voltage, D batteries are capable of producing more power.

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@zebarah: Isn't that only because it has a higher capacity though? For instance if I run AA with 2.9 Ah at 2.9 amps and 1.5 volts it would only last an hour.. where as the D Battery has the capacity of 12 Ah, theorodically you should be able to make it run at 12 amps for an hour. That said, in 1 hour, AA batteries are capable of producing 4.35 watts, where as the D batteries can provide 18 watts.

So in theory, the D battery can produce more power over the same amount of time, or the same amount of power for longer then the AA batteries.

Now I don't know if a D battery really can reach 12 amps (or heck, why not 24 amps for only 1/2 an hour? 36 amps for 1/4 an hour?).. I dunno if there is a limitation as to how many amps a battery can put out over a space of time whether long or short.

However it comes back to the larger capacity that D batteries have... And even if AA batteries can only produce 4.35 watts while D Batteriescan produce 18, it is still only 1/4th the power roughly.

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@robbit73: A piece of aluminum foil does the trick.

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@bmseaton: "So in theory, the D battery can produce more power over the same amount of time, or the same amount of power for longer then the AA batteries."
Power is equal to the amount of work divided by time, so saying something produces more power in the same amount of time is just saying that it can produce more power.

"I dunno if there is a limitation as to how many amps a battery can put out over a space of time whether long or short."
That's what I meant by it having a higher maximum current rating. AA batteries cannot produce the same amount of current as a D cell can, which is the main reason that different cells are used, not just the life of the battery.

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@jay481985: Agreed. I've used aluminum foil, coins, washers, etc. with my eneloop spacers, but it's just the fact that it's an inconvenience, however minor. It's seems to me it's an issue easily fixed.