Instructables
A simple modification will allow you to use a $20 AA Energizer cell phone charger with any USB device to charge your cell phone, iPod etc. *(note in testing it does not have enough juice to charge an iPhone 3G)

It cost about the same as the minty boost ($20) and is about the same size. Almost no assembly is required by compairson. I completed this project with parts I had lying around. Not sold yet? Did I mention it has flashing blue LED's?
 
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Step 1: Parts

Here are some of the parts and tools you will need.

- The energizer AA battery charger for cell phones (found at many drug stores)
- USB extension cable ( Comes with many different USB devices/dongles, you or your friends probably have some in a drawer somewhere)
- Soldering Iron and Solder ( I like the radio shack butane powered ones because they heat up fast and have no power cable to catch on things, also highly portable)
- Wire strippers ( these came from the dollar store and they are 3+ years old! )


Disassemble the usb charger. It is pretty strait forward. The cap with the springs pops off easily to remove the batteries. The remaining cap can be pried off with a screw driver or by pulling the two halves of the casing apart. What we want is to get at the circuit inside the cap.
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dannysland4 months ago

When these were available in the stores, it was hard to get different adapters without buying another whole unit. Therefore, I really appreciate how this Instructable turns the Energi-to-Go into a universal charger.

These still turn up occasionally in the original packaging at Goodwill.

energizerhack.JPG
Kohaku5 years ago
A local store has stacks of these Energizer mobile chargers for £1.99 each so I grabbed one, neat device except it doesn't quite like being used with rechargable AAs, it'll only charge your mobile/mp3 etc. if the rechargable batteries are freshly charged, once they get too low a voltage it refuses to output any voltage. I have managed to power my Archos AV500 with one for 50 minuites though using freshly charged AAs. I also looked up the specs of the DC boost chip they use, it's designed to work with pure 3v input and has little tolerance for over/under voltage so I haven't tried hooking up 3x rechargable AAs to it yet in case I fry it. One day I'll get bored and say what the flip & see what input voltage it can actually take.
WHERE EXCATLY IS THIS SHOP
kedwa30 Kohaku3 years ago
Thanks so much for that explanation. I had alway wondered why, when I start charging my phone with it, if I accidentally disconnect, it will not finish off the battery. I came across this article while I was looking for a way to use D-cells or rechargable AA batteries to power my phone since the battery is shot but I don't want to pay for an exact replacement. I am one of those rare people that does not care to have a flimsy credit card sized phone and would actually prefer a heavier, more rugged phone. In any case, I realize now that I will not be able to use this DC boost chip for that. My next search will be for a wind-up dynamo. :-)
vcbc Kohaku5 years ago
Yes, thats also the case with the Duracell My Pocket Charger... its sucks... Running 3 rechargeable AA batteries does kill the unit, i tried it myself. The batteries were sitting there for a few days after charging, so there was some discharge. I didnt bother to test it. I was going to try out the Sanyo Eneloop Batteries, because those have low discharge maybe it may work better. But I never seen them in stores and havent got the chance to order one yet.
DavidDanna vcbc4 years ago
It's been a year and a half just about but I have been experimenting with using three AA NIMH rechargeable batteries attached to the boost chip from the Energizer Energi to Go pack.

The boost chip from this pack is set to operate in a voltage range from the low of 2.7 volts to the high of 3.6 volts, although it will only utilize 3 volts on the input. It is designed to work specifically with Disposable Lithium batteries, which start with a battery post voltage of 1.8 volts each, then down to 1.5 nominal.

So at first glance, it would seem that three AA Nimh batteries could blow it, as they would run 3.6 volts nominal from the three batteries, and would start with a post voltage of nearly 4.3 volts. But hold on there!!!

The chip that Energizer uses will take a voltage all the way down to .7 volts, or all the way up to 6.5 volts, so three batteries won't blow it, however Energizer programmed the chip to be set specifically for Lithium's, so it won't operate if you try three Lithiums, or four Nimh batteries. That being said, when the three Nimh batteries start out, is shouldn't work... BUT HOLD ON THERE!!!

Now the next part is the fun part. The chip documentation from the manufacturer states that it has over voltage circuitry that gives it an extra 1.44 volts on top of the programmed operating current. Since Energizer set this to operate at 3.0 volts, it will safely operate at 4.44 volts! Divide 4.44 by three and you have 1.48 volts per battery, which is more than the max post voltage of a nimh battery!!!

YEAH!!!

The real big positive here is that three nimh batteries will drain about 94% capacity before they shut off when put into this three battery configuration. That's about four hours of play time.

The chip gives you up to 630 milliamps, which is 130 more than the mintyboost. You can now get the Energy to Go unit shipped from Ebay for under $5 dollars. With any large Altoids tin, a few extra parts (need resistors to set up charging for Ipods, Zunes, etc...) you can have your own boost supply for under $15!!!

Now here is the fun part... connect more than one of these together in parallel, and you increase your current! I have done this, giving me a kit with six batteries and 1.26 Amps of current power! I can power my Kodak Zi8 camera for two and a half hours straight in HD recording without having to worry about running out of power!!!

AWESOME!!!

If you ran three of these in parallel, which I have done, you can charge a Zune or an Ipod in about two hours flat.. and do it three times!!! (but the battery pack weighs more than your head!!!

So there you go! With the Energi to Go, they have such a great intelligent circuit, and you can get them dirt cheap, it is pretty darned easy to put together a cheap alternative to the Mintyboost, and get more life out of it as it uses three batteries instead of two! (plus, if you do it right, you have space left over for actual Altoids in the tin, great if you have terrible death breath!!!)

Ciao!!!
Hm. Sounds like crossing one of these with the Joule Thief, to let it run the batteries all the way down, might be worth considering.
_Scratch_4 years ago
im pretty sure a usb is limited on a computer to about 2 or 3 amps, so a strong Ni-Mh AA battery should work, or else how could you charge the Iphone? Cuz i got 2.5 amp AA batteries around.
Actually, USB is 5VDC at 500mA to an 1A :)
you need to connect the data lines (green and white) and your iphone will think it is a charger
Colonel884 years ago
I burn myself all the time and brag to people, "I am such a man. I got burnt and i survive!". Lol not really but i get burnt a lot/.
Haha, I get burned every time.
computo4 years ago
I have a much easier way... go to ebay, look up: portable usb charger AA. and buy it and mod it to any way you want... you can find one for $5, i love to mod stuff but there is a cheaper way...
civicturbo4 years ago
Nice! I bought several of these on clearance from Target any others for under 5 bucks just for the energizer lithium batteries they included.
ktalex4 years ago
i do that all the time i always burn myself with the soldering gun.
grngrn5 years ago
where can you buy one of those energizer chargers, I have searched all over for one and can't find it.
I got mine at the Krogers Grocery store.
junits15 grngrn5 years ago
lowes home depot..................... stores like that
Dollar General, Maybe Wal-mart
grngrn5 years ago
if the circuit board inside of the energizer is similar to a minty boost, would it be possible to use it in place of one for the solar powered iPod charger. (http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/)
mman1506 grngrn5 years ago
yes it will probbaly work because the circuit is about the same with a voltage stepper and a regulator it just may not charge as efficently or as easy to hack as a mintyboost
+1 for this question. I am looking at the same thing.
wierd idiot5 years ago
Jee that circuit board looks awfully big. :-P
what happen if you forget to pay for your Internet?
well it stopped
abadfart5 years ago
lol i burnt myself on a heat gun
awang85 years ago
Actually, the MintyBoost is better because it can supply data and the tin is sooooo minty*. *Do not eat MintyBoost.
pcmofo (author)  awang85 years ago
I'm not sure what you mean it supplies data. It is roughly the same size as the monty boost. Also if you already have this charger and a USB cable lying around like I did you can do this for free in a few minutes.
What he means by "supply data" is that the minty boost outputs "reference voltage" on the two data pins. This is what tells devices like the iPhone 3G and the RAZR to start charging. I believe it is around 2 - 2.7V that must be supplied on the data pins. This is what you are referring to when you speak of the resistor in the tip of the Motorola mini-usb chargers. It just causes a voltage drop across the pins to indicate the "reference voltage". I found all this crap out when I began modifying my LED camping lantern (that can be powered with a hand crank) to charge my iPhone. I am working on installing the inline voltage divider to take care of this. I might post the instructable when finished!
finnrambo5 years ago
Great instructable but are their cheaper chargers around?
jaythedogg5 years ago
Remember, when desoldering, you MUST keep your temp just low enough to melt the solder to avoid any possible heat damage to surrounding circuitry & components!
jaythedogg5 years ago
How do they fit all of that circuit board into that teensy space? lol JK, great instrctbl man!
jadi9295 years ago
i had an energizer charger which already had a usb attached to it, what i did was though, followed your method to put in place a female usb on a solar charger and was able to charge with batteries with solar power, pretty cool i havent actully tried like an mp3 player with the solar power, i just cant seem to find one around lol
sstought5 years ago
I tried this out, and it seems to have mostly worked, but I ran into two problems. First, it blinks all the time when the batteries are in, even without anything connected. Second, I checked it out on my multimeter, and its putting out 5.46V, and I couldn't get a steady reading to check the amps. I'm kinda worried about that, so I'm going to use it. Any advice?
pcmofo (author)  sstought5 years ago
The blinking happens even before modification... nothing you can do about that besides putting some tape over it. The 5.46 volts is ok for most devices. Unless you have some expensive or sensitive device this should be fine.
Would it not take a while to charge, as USB ports can only give out 100ma, unless they have been "requested" more by special circuitry...
ur talking bout computer mice...only computer mice need 100mA
it's not a matter of need, rather asks for i think
I believe it's 500ma, actually (5V, 500ma, 2.5W) At least, thats what I've heard everywhere else.
frollard6 years ago
Great little instructable! One thing I've noted is you need a resistor between the data pins on the cable to make various electronics think that they are attached to a proper charger. *i.e. my razr wont charge unless either the resistor is in place, or software via usb tells the phone to start charging.
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