how does a cell phone detect a "genuine" battery

Here's the next item on my "to-fix" list while home for the holidays...

I have before me a Motorola E815 cell phone which will not charge. The battery is fine, just the phone won't make a connection to the charger. I found an old LG cell phone with battery, which works fine.

Since every single cell phone I've ever seen uses a 3.7V Li-Ion battery, and since I don't have a programmable voltage supply with me, I figured I could use the LG cell phone to charge the Motorola battery. The LG cell phone and its battery have 4 contacts:

| | | | NEG NEG MYSTERY POS

and the Motorola cell phone has 4 contacts as well:

| | | | NEG NEG MYSTERY POS

I figured I could just connect the +/- terminals of the LG phone to those of the Motorola battery, and the Positive terminals together, and then the LG phone would see it has a drained battery and merrily charge it up.

Not so! When I did this, the LG phone said "Use genuine battery!" and refused to charge it. WTF?!?! It seems like there's some kind of "counterfeit detection" circuit in the battery to make it harder to make cheap knockoff batteries. I assume this comes from the "mystery" contact. Is there information somewhere on how to fool this idiotic counterfeit detection circuit?

Thanks,

Dan

Reply to
Dan Lenski
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Hi Dan...

It's for your own protection, I'd recommend not trying to defeat it.

Take care, and happy holidays.

Ken

Reply to
Ken Weitzel

Thanks Ken, but I don't need any protection :-) I have a long history of doing things with my electronics that they were never meant to do, and it's worked well for me.

It's ridiculous that a cell phone demands a particular brand of battery, considering that essentially all cell phones use 3.7V LiIon batteries which differ only in capacity and shape. Plus I don't really care about protecting the phone, since I only want to use it as a charger for this battery.

I'm wondering if the "genuine battery detection" is something trivial like "connect a 100k resistor between the mystery contact and ground" or something complicated involving a microcontroller in the battery that uses some serial protocol to communicate a message back and forth.

Dan

Reply to
Dan Lenski

put a scope on the mystery leg, you'll most likely see a serial stream coming out of it. try blocking off that leg.

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Reply to
Jamie

Some inkjet cartridges are chipped to prevent refilling or cloning. Could be a similar nasty trick.

Reply to
Homer J Simpson

Hi Dan...

Not so sure that we don't need a bit of protection... thinking of the exploding and burning batteries in laptops recently... third party and counterfeit batteries are out there, and it won't be long before making them with small capacity and mis-marking them, so...

Anyway, I have no idea, other than guesses. Jamie suggest that it might be a serial connection to the phone. That sounds good, if LG doesn't want you to buy any of their competitors products, but might be expensive to implement.

I'm wondering if it might not be as simple as a temperature detector... something as easy as a pair of diodes back to back. Or maybe even a thermal fuse.

Another thought is if someone here has a battery that's dead beyond any use at all, perhaps they'd open it up and see what's in there?

Wish I knew more. :)

Take care.

Ken

Reply to
Ken Weitzel

Just because they are the same voltage doesn't mean that they use the same cells inside. Maxim and others make ICs for this application.

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Reply to
Michael A. Terrell

On Sun, 24 Dec 2006 15:06:24 -0800, Dan Lenski Has Frothed:

I'd listen to Ken. Hate to see you have a phone in you pocket and have the LiON battery do a meltdown.

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Reply to
Meat Plow

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Reply to
Bob Urz

Many of the manufactures are starting to make their products in a manner to have increased safety. Inside of many of the dedicated batteries, the manufactures are using chip technology to not allow them to be charged if they are not the original product. The manufactures are trying to protect themselves and the end users, regardless of the knowledge of the person trying to defeat its purpose.

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JANA
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Reply to
JANA

The only thing they're protecting is their profit margin.

Reply to
AZ Nomad

In article , snipped-for-privacy@gmail.com (known to some as Dan Lenski) scribed...

I was reading about this in the industry trade rags (Electronic Design, EETimes) this last summer.

Unfortunately, it's not likely to be easy to defeat. The system I came across was described as having a custom IC (a microcontroller plus a serial port) built right into the battery. Said microcontroller is mask-programmed with a unique and encrypted ID at the time of manufacture, and it enters into a complex handshaking sequence with the phone's innards before the phone will accept it and power up.

I'm not saying it can't be cracked -- Anything electronic can be. However, the kinds of resources and test gear you'd need to do it would exceed, by many orders of magnitude, the cost of a genuine battery gotten from, say, Greed-bay.

I used to think the counterfeit detectors were a bad idea. However, given all the low-quality knock-off batteries that have exploded and burned in recent years, some causing nasty injuries, I'm not so sure.

Happy tweaking.

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Reply to
Dr. Anton T. Squeegee

Like the ink for inkjet printers - it's more expensive than the finest champagne.

Reply to
Homer J Simpson

AZ Nomad hath wroth:

No, they're protecting themselves against liability issues. Personally, I don't mind paying a bit extra to avoid a potential fire or problem.

Note that the defective Sony batteries were caused by microscopic impurities in manufacturing.

There's a good article on the safety of LiIon and LiPo batteries in the current issue of Nuts and Volts, but it's not online.

Meltdown is sorta fun, but not inside my cell phone or laptop.

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Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
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Reply to
Jeff Liebermann

bullshit.

If the battery explodes and the phone is operating within specs, it is the batteries fault. Not the carrying case. Not the owner. Not the clothing being worn by the cell phone owner. Not the power lines leading to the house where the phone was charged.

Reply to
AZ Nomad

On 24 Dec 2006 14:46:38 -0800, "Dan Lenski" put finger to keyboard and composed:

Is it possible to swap the electronic innards? If so, is there any reason why it would not be safe to do so? Wouldn't the cell chemistries be identical?

- Franc Zabkar

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Reply to
Franc Zabkar

AZ Nomad hath wroth:

Can you offer a better explanation of what went wrong with the Sony batteries? I'm only recycling what I've read on the internet which also notes that manufacturers are switching to metal oxide insulators that will not conduct heat or cause a fire. Perhaps you have inside information? URL's that offer explanations other than crud imbedded in the polyolefin insulators are acceptable.

Correct. I have the honor of suing the manufacturer in China if my house burns down as a result of having the cell phone catch fire in the charger. Chances of collecting damages is about zero. Granted, the risk of fire is very low, but I'm not interested in proving the point.

How about counterfeit battery incidents? Is that sufficiently relevent?

(Lots more. Just search Google for "counterfeit batteries")

NEC also makes counterfeit battery detector chips:

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Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
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Reply to
Jeff Liebermann

Respectfully suggest you put suing someone to reclaim your monetary losses if your house burns down on the back burner.

Think instead about who and how you can sue for the losses of your kids and/or grandkids if they're sleeping in your house when it goes up. Or riding in your car when it "explodes" and indirectly causes an accident. Puts a whole new light on it, eh?

Take care.

Ken

Reply to
Ken Weitzel

Putting an anti-competitive chip in those batteries wouldn't have made any difference.

Reply to
AZ Nomad

Ken Weitzel hath wroth:

One my pastimes is collecting product liability horror stories. There's a real possibility of winning such a judgment based on past precedents. However, that usually only works for the initial litigation as subsequent "me-too" litigation tends to be far less successful. There are exceptions (asbestos, Vioxx, etc).

Agreed. However, methinks you misread what I scribbled. I didn't recommend litigation. I suggested that one buy an approved battery to avoid the problem in the first place. I also mentioned that litigation against a battery counterfeiter in China is essentially futile.

However, I'm starting to wonder if genuine OEM batteries will really will help. The original exploding Nokia batteries were genuine Nokia and not counterfeits. Some batteries apparently have no short circuit protection.

What bothers me is the number of my customers that don't even bother to check if their laptops have potentially defective Sony batteries. I've had to call them for the models and serial numbers.

Assorted battery recall pages:

I think taking care pills requires a prescription.

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Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
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Reply to
Jeff Liebermann

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