You know you are a geek when...

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jesse

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Jesse
You know you are a geek when...you lose your cell phone charger on Christmas day and no stores are open. You don't want to have to wait an entire day to buy a charger.

So you...

Take the phone apart to figure out the polarity of the charging port.

Solder new wires onto the port.

Hot glue the charging port to prevent it from shorting out with each other.

Check the manufactures website to try to get the charger voltage. No luck. You go online and read about lithium poly batteries and how they are charged.

Come up with a power source that produces about the correct voltage based on your guesstimation after reading.

Charge it.

Remove the hot glue.

Unsolder the wires

Clean up the connector.

..and you now have a fully charged phone!!

geekag6.jpg


http://jesseangell.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=223&g2_serialNumber=1
 
Hmmm...the cell phones I've had were all stamped 3.6V on the lithiums.

T610?


-Rich
 
rpadula said:
Hmmm...the cell phones I've had were all stamped 3.6V on the lithiums.

T610?


-Rich
Click to expand...

But it takes more than 3.6 v to fully charge a 3.6 v battery.

Jesse, I assume you realize that it's easy to get a lithium battery to catch fire when overcharging it
 
lancefisher said:
But it takes more than 3.6 v to fully charge a 3.6 v battery.

Jesse, I assume you realize that it's easy to get a lithium battery to catch fire when overcharging it
Click to expand...

I realized that. The cell phone has integrated circuitry for handling the charge. It was a matter of waiting until the charge indicator no longer progressed on the phone and increasing voltage after that. Somewhere around 4.235 volts (per cell) is the critical number that will start to cause problems. In theory the charging circuity should quit the charge if it reaches this level. But I preferred to just baby it up until it was near full charge. Constant monitoring including battery temperature was done. I actually stuck a temp probe on the battery. Not sure if my method of slowly increasing voltage is good on the battery. But I don't care if it decreases the life a bit. It's an old battery anyways.

rpadula said:
Hmmm...the cell phones I've had were all stamped 3.6V on the lithiums.
Click to expand...
Does your car alternator output an even 12 volts? Not only that. Most full charge lithium poly batteries will be about 4.23 volts and range down to around 3.2 volts ( i think ) before it disconnects the battery. Fully discharging a lithium will trash it.
 
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Real geeks would have just used electrical tape not a glue gun. Glue guns are what Martha Stewart types use ;)
 
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Personally, I'd have just enjoyed the silence for a while. Sometimes not being able to reach someone isn't the end of the world.
 
smigaldi said:
Real geeks would have just used electrical tape not a glue gun. Glue guns are what Martha Stewart types use ;)
Click to expand...

Haha. Actually a glue gun is the most amazing thing in the world when you have to solder two things real close together that have the ability or potential to touch each other if moved in a certain way.

Plus it provides a lot of strength.
 
jesse said:
Haha. Actually a glue gun is the most amazing thing in the world when you have to solder two things real close together that have the ability or potential to touch each other if moved in a certain way.
Click to expand...

Well after the Martha Stewart crack I expect to get slammed for the next bit.

When you have two wires like that close together use some nail polish. I keep a bottle of the bright red stuff because it is easy to see when it is on. It coats the connections very easily and also comes off lickety split with heat or a little acetone. I have used that stuff for years and it works great. Also you do not need any special tools to apply it.

Plus if you are feeling fancy you can do your toes ;)

jesse said:
Plus it provides a lot of strength.
Click to expand...

That is very true
 
smigaldi said:
When you have two wires like that close together use some nail polish. I keep a bottle of the bright red stuff because it is easy to see when it is on. It coats the connections very easily and also comes off lickety split with heat or a little acetone. I have used that stuff for years and it works great. Also you do not need any special tools to apply it.
Click to expand...

Never thought of that. But if you get hot glue really hot it is very thin and easy to apply. Real simple to ensure separation.

When you are done--you just pull it right off..No problem.
 
jesse said:
Does your car alternator output an even 12 volts? Not only that. Most full charge lithium poly batteries will be about 4.23 volts and range down to around 3.2 volts ( i think ) before it disconnects the battery. Fully discharging a lithium will trash it.
Click to expand...
Yes, I'm aware that 3.6V is just the nominal cell value. I suppose my Bachelor's and Master's degrees in Electrical Engineering might have something to do with that. :D The "un-typed" finish to my original post should have said 3.6V would give you a good starting point, as opposed to the higher voltages required by multi-cell packs.

jesse said:
I realized that. The cell phone has integrated circuitry for handling the charge. It was a matter of waiting until the charge indicator no longer progressed on the phone and increasing voltage after that. Somewhere around 4.235 volts (per cell) is the critical number that will start to cause problems. In theory the charging circuity should quit the charge if it reaches this level. But I preferred to just baby it up until it was near full charge. Constant monitoring including battery temperature was done. I actually stuck a temp probe on the battery. Not sure if my method of slowly increasing voltage is good on the battery. But I don't care if it decreases the life a bit. It's an old battery anyways.
Click to expand...
I doubt you actually babied the battery by inching up from 3.97V as shown on your DMM in the pic. The cheap wall warts we get from China are not very well regulated voltage-wise. I think most are just half-wave rectified (lucky to get one diode and a cheap cap), so precision at the AC charger port on the phone wasn't a neccessity.

In all likelihood, you were feeding a DC-DC power supply stage, which would provide the proper voltage, current and temperature limiting required by the battery. Yes the charging algorithm will do most of the heavy-lifting, but good designers (which I believe Sony Ericsson are) will have hardware protections in the charger as well.


-Rich
/Ramblin' Wreck
 
rpadula said:
In all likelihood, you were feeding a DC-DC power supply stage, which would provide the proper voltage, current and temperature limiting required by the battery. Yes the charging algorithm will do most of the heavy-lifting, but good designers (which I believe Sony Ericsson are) will have hardware protections in the charger as well.
Click to expand...

Most likely. I was just taking the cautious approach. I ended up pushing it up to 4.22 volts and kept monitoring battery temperature. I never did receive a full charge indication just an almost full charge indication which turned out to be pretty damn close as the battery was throwing out about 4.2 volts after unsoldering everything and checking it.

I was taking the safe approach for sure. But I really didn't want to have to deal with phone/battery damage or worse yet a fire.
 
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jesse said:
I was taking the safe approach for sure. But I really didn't want to have to deal with a fire.
Click to expand...

Wise to be safe but all of the large cellular manufacturers put 'smarts' in their phones for the charging circuit and 'smarts' in the batteries to prevent or at limit the chances of fire. Too often after market chargers, if allowed direct access to the battery without conditioning could result in damage to the battery and damage to the phone user.

http://www.hardwaresecrets.com/article/326
 
I got a hand crank charger with several adapters for all manner of cell phones as a Christmas gift. The package says two minutes of cranking will charge the phone for 6 minutes of talk time.

Len
 
smigaldi said:
Well after the Martha Stewart crack I expect to get slammed for the next bit.

When you have two wires like that close together use some nail polish. I keep a bottle of the bright red stuff because it is easy to see when it is on. It coats the connections very easily and also comes off lickety split with heat or a little acetone. I have used that stuff for years and it works great. Also you do not need any special tools to apply it.
Click to expand...

you joke about him being Martha Stewart for using a glue gun, and then you use fingernail polish?! :rofl:

It is a good idea, though!
 
Curious..isn't fingernail polish flameable? Could be a problem if it hasn't dried yet and something shorts out.

I had that happen once with liquid electrical tape. it is very flameable in it's liquid state...Something shorted out..and started a decent fire.
 
jesse said:
Curious..isn't fingernail polish flameable? Could be a problem if it hasn't dried yet and something shorts out.

I had that happen once with liquid electrical tape. it is very flameable in it's liquid state...Something shorted out..and started a decent fire.
Click to expand...

Yeah 3.6v will cause a huge explosion with the high flash point and tiny dab of finger nail polish :no:.

BTW it is an acrylic sealer and that stuff has been used for decades on electrical circuits.
 
smigaldi said:
Yeah 3.6v will cause a huge explosion with the high flash point and tiny dab of finger nail polish :no:.

BTW it is an acrylic sealer and that stuff has been used for decades on electrical circuits.
Click to expand...

Well. I had a really bad experience with six volts and liquid electrical tape once that produced a fire on a work bench that was...actually a challenge to control.
 
jesse said:
Most likely. I was just taking the cautious approach. I ended up pushing it up to 4.22 volts and kept monitoring battery temperature. I never did receive a full charge indication just an almost full charge indication which turned out to be pretty damn close as the battery was throwing out about 4.2 volts after unsoldering everything and checking it.

I was taking the safe approach for sure. But I really didn't want to have to deal with phone/battery damage or worse yet a fire.
Click to expand...

JOOC were you connecting directly to the battery (I think you said you were) or the phone's power input conection? The latter would have allowed the phone's charging control to work normally, but might be tough to gain access to.
 
You know you are a geek when...

you read this whole thread.:yes:
 
lancefisher said:
JOOC were you connecting directly to the battery (I think you said you were) or the phone's power input conection? The latter would have allowed the phone's charging control to work normally, but might be tough to gain access to.
Click to expand...


No I ended up connecting to the phone power input connection ( i think ). And yes..It was pretty tough to solder onto. There is about 1 mm of seperation between the positive and negative. I charged it though pretending I was connected directly to the battery just to be safe. I didn't really trust that the phones ciruitry would properly protect from overvoltage nor did I know the voltage the phone expected as I couldn't find any specs that stated it.
 
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jesse said:
No I ended up connecting to the phone power input connection ( i think ). And yes..It was pretty tough to solder onto. There is about 1 mm of seperation between the positive and negative. I charged it though pretending I was connected directly to the battery just to be safe. I didn't really trust that the phones ciruitry would properly protect from overvoltage nor did I know the voltage the phone expected as I couldn't find any specs that stated it.
Click to expand...

There's an easy way to determine the approximate voltage required by almost anything with a microprocessor in it, just remove the battery and slowly turn up the voltage until it comes out of reset then add 10%.
 
lancefisher said:
There's an easy way to determine the approximate voltage required by almost anything with a microprocessor in it, just remove the battery and slowly turn up the voltage until it comes out of reset then add 10%.
Click to expand...

Nice to know. You really just need to teach me everything you know.
 
Nothing wrong with electrical tape! You shoulda seen the scramble that broke out when I gave a box of duct tape and screw drivers as a present for my EAA chapter one year! I can't imagine what woulda happend if I would have bought electrical tape, its even more of a multi use especialy for those aviator types.
 
Brian Austin said:
Personally, I'd have just enjoyed the silence for a while. Sometimes not being able to reach someone isn't the end of the world.
Click to expand...

Exactly! My blackberry is constantly chiming with one notification or another - it's insane. There is no greater feeling than pulling the battery and watching the little screen go black.

Sometimes, letting go feels 100 time better than holding on.

Cheers,

-Andrew
 
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