Cellphone battery booster built at the checkout counter

posted Oct 29th 2011 11:01am by Mike Szczys
filed under: cellphones hacks

Build a phone charge extender in 5 minutes inside Radio Shack

Video Link...
http://www.youtube.com/watch?feature=player_embedded&v=RVUbIMncjqM

When you’re away from home and your cellphone runs out of juice it can be a real downer. Sure, you could find a store and buy a wall charger, but wouldn’t it be more fun to build your own battery booster without using tools? [Spiritplumber] did just that, popping into a Radio Shack for the parts, then making his how-to video (embedded after the break) while standing at the checkout counter. You can see he has set his camera on top of the battery display case and got to work.
He’s using four D cell batteries to provide 6 volts of power. Assuming your phone charges at 5 volts this is going to be just a bit too high, even though there’s some tolerance with most phones. To overcome that obstacle he added a diode to the circuit, taking advantage of the 0.7 volt drop that it brings to the mix. Grab a plug adapter for your model and then just hand twist the connections. [Spiritplumber] admits it would be better to solder these, but in a bind you can get away with it. We looked up some prices for this method and we figure this would cost around $18 (batteries included) depending on the price of the plug adapter for your phone.
Of course if you’re just looking for a way to charge your phone without paying consumer prices there are ways of accomplishing that as well.

[Thanks Mkb]
Comments [15]

tagged: battery, boost, charger, radio shack, smart phone

15 Responses to Cellphone battery booster built at the checkout counter

Dug says:

October 29, 2011 at 11:19 am

Great hack, simple but the use of the diode makes it.
Maybe I’m missing something; but is there a reason why he says to use Alkaline rather than rechargables? What’s the problem with using rechargables for this?

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drew says:
October 29, 2011 at 11:37 am
I’m guessing it’s because rechargeables have a slightly lower voltage.

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Harvie.CZ says:
October 29, 2011 at 1:51 pm
Very strange. USB chargers are 5V… alkalines are 1.5V, rechargables are from 1.2 to 1.3V
4*1.5 = 6V
4*1.2 = 4.8 to 5.2V
But! the diode is essential. I tried charging my G1 using 4 AAs without the diode and i think that it made my phone discharge even faster than without it :-)
BTW I understand why owners of G1 are doing desperate batterypacks like this one :-D

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Bodeddie says:

October 29, 2011 at 11:40 am

The reason rechargables won’t work is voltage. Alkaline or even old fashioned carbon-zinc batteries are 1.5V each. Times 4 makes 6V. Rechargables are not 1.5V, but 1.2V for NiCad and 1.25V for NiMH. 4 times 1.2 is only 4.8V, not enough voltage! 4 times 1.25 is 5V, which is right on the edge of usability but will quickly drop under load to below 5V.

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Dug says:
October 29, 2011 at 11:51 am
Ah, if that’s the only reason; could this be done with 5 rechargables; taking it up to 6 volts? Or is it likely to kill the batteries?
Would a voltage regulator would be a better bet to use? I have a few 5v ones lying around…

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- spiritplumber says:
  October 29, 2011 at 12:01 pm
  That is the only reason yes :)
  While RS has 7805s that you can use, they tend to have a higher dropout voltage than 1v, so 4 batteries wouldn’t work to give you 5v. And you’d need to buy two battery holders because RS doesn’t carry holders that take more than 4 cells.
  The challenge was “build it quickly and now”.

wethecom says:

October 29, 2011 at 11:40 am

Rechargeable battery’s dont work why?

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wethecom says:
October 29, 2011 at 11:45 am
i think you will find your theroy wrong and the phones recharging circuitry will take about any voltage bellow 5V with only a loss of effectiveness.but would be noticeable for what your doing.but it would have a great gain by being rechargeable cells

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- John Smith says:
  October 29, 2011 at 11:50 am
  Try it and get back with us.

spiritplumber says:

October 29, 2011 at 11:55 am

Yeah it’s just the voltage :) plus the fact that normally rechargeables aren’t sold full. The idea here is “I know I have to livestream something in one hour, let me walk into a rdaio shack”.

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matt says:

October 29, 2011 at 12:18 pm

radio shack should sponsor a series of these “checkout counter” hacks! :D
if it isn’t already… >_>

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biozz says:

October 29, 2011 at 1:13 pm

whats the reliability of using a diode as a “regulator”?

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Harvie.CZ says:
October 29, 2011 at 1:55 pm
I don’t think that diode is there to act as regulator. IMHO it protects the alkalines to be charged from phone when they run low…

http://hackaday.com/2011/10/29/cellphone-battery-booster-built-at-the-checkout-counter/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+hackaday%2FLgoM+%28Hack+a+Day%29&utm_content=Google+Feedfetcher

That could come in handy in a pinch. Sometimes, "The Show Must Go On"!:) I didn find it odd that someone with so much kwnoledge of Eletronics. He didn't know the difference between Duct Tape and Electrical Tape... He kept calling the Black Electrical Tape that he was using "Duct Tape". There's a Huge Differnce...

Duct Tape Pics (Above)

Electrical Tape Pics Above (insulating tape) is a type of pressure-sensitive tape used to insulate electrical wires and other material that conduct electricity. I'm sure He and You already know this. But, just in case;) Go there...
http://en.wikipedia.org/wiki/Electrical_tape

I ran Sound for Bands for 12 years and I know how important on little bit of non working Tech Can be... Once I had to made a Run to Radio Shack on a Sunday Morning, just looking for Balanced (TRS) Male Connector to Hoock up a Crucial Ampt to the PA. The owner of the PA didn't know Ballanced from Unballanced, signals. I was just helping out with the Setup and Mixing... Would you believe it? The local Radion Shack in Fort Wroth TX, didn't even have one Ballanced TRS Male Connector!:O So, I went back and "Borrowed the Male Connector off of Someones old Set of Head Phones. That was my Back up Plan... (I allways try to have one). Sterio Head Phone Connectors are not the same ecact demensions as Ballance TRS Connectors (American). But, as long as the wires are not moved, wiggled, tripped on etc. They will work in a Pinch...

After watching the Video. I got to thinking... You could probably use a 6 Volt Lanturn Battery instead of buying the D-Cells and the Battery Holder.

(6 volt Lanturn Battery Pic Above)

And if you weren't near a Radion Shack. You could go to your local Auto Supply to get your Parts. Well, except the Adapter for your Pnone. But, you probably already have one of those, that came with your Car - Mobile Phone Charger or USB Charger, Right? So, at the Auto Supply, get a 6 Volt Lanturn Battery and instead of the Diode, which you most likely can't get at the Auto Supply. Get a Ballast Resistor (Heavy-Duty Ceramic Resistor for Use with Ignition Coil).

(Ballast Resistor Pics Above)

Nnow, I'm not sute if the drop in voltage, when used on a Lanturn Battery, will be right. Might be too much, using the standard Resistors available at the Auto Supply. So, you could just get 2 Resistors and hoock up to your Auto's Battery (if it is 12 Volts) and then you will end up with 6 Volts. I had a 1954 Chevy Belair, and that is how it was converted from the original 6 Volt System, for use with a 12 Volt Battery. That's what made me think of this... Still, you would need to be able to check your voltage. To make sure that you arent going to Blow Out the Circuites in your Mobile Phone!.. I haven't tried this. I actually don't even have a Mobile Mobile ("Cell" Cellular Tech hasn't been used for several years now in America). Anyway... just a few alternate ideas on how to get buy. But, of course. Mobile Phone Chargers are so Cheap these days... The only real reason I can think of for doing this. Is for the Sheer Fun of being like McGiver;)

Don