Slightly OT: Recharging Mobile batteries

Hi,

My mobile is refusing to charge the battery. For reasons that I don't need to go into (but will if you want), I suspect that this is a fault with the phone not the battery.

Can I recharge the battery by just connecting the terminals on the charger plug to the terminals on the battery, for an hour or so, or is something more complicated than this required?

TIA

tim

Reply to
tim
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Quite impossible to tell. For starters, it depends *heavily* on what phone that is. Somewhere in the chain between the mains power and the accumulator cells, there *must* be an accumulator charge/discharge control circuit. As long as you don't reveal the model of that phone, it's anyone's guess where that circuit might be. It could be in the battery itself, or in the phone, or (possible, but much less likely) it could even be in the charger.

You'll most likely find that the number of terminals on the battery isn't even the same as the number of pins on the charger's connector, and that's before we start considering unknown polarities and pin-to-pin mappings.

--
Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.
Reply to
Hans-Bernhard Broeker

It is worse than that. If the battery is charged at to high a voltage it can fail or catch on fire. It depends on where the charge controller is. Li-Ion are not toys. Find a different phone. Or use a voltage regulated current limited power supply.

Reply to
Neil

This is no big deal. The phone doesn't work with it and it has no other use.

I have a diferent phone. But I need to make the old one work so that I can copy my phonebook to the sim (never having lost a Phone like this before it's not something that I considered necessary in normal use)

To charge the battery or operate the phone?

Tim

Reply to
tim

Li-ion batteries have a heap of protection to stop them from catching fire from overcharging or short circuiting. One battery I saw included a little PIC to monitor the voltage on each cell. There are fuses, thermal fuses and all sorts of control circuits. Also, if a battery gets discharged too far then the protection circuit will prevent it from recharging and it can't be reset even if you get new cells. When that happens it's a dead battery and time to dispose of it, as many laptop owners can tell you.

If you mess with Li-ion then do it outdoors away from anything that you don't want to burn.

Peter

Reply to
Peter

It is rather. One of the failure modes consists of shooting flames in one or more directions for a foot or so. If you're going to futz with Li batteries, make sure there's nothing nearby that will burn.

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Reply to
Grant Edwards

*To* the SIM, or *from* the SIM? Remember: you can put that SIM into any other phone, and it'll at least be able to read it. There are even dedicated devices to copy SIM contents directly from card to card. Not cheap at first sight, but a damn sight cheaper than the damage a mis-charged Li-Ion accu can do.

And operating the phone with the broken accu and the charger both connected doesn't suffice?

Honestly, I'd say your best bet is a phone shop. They're usually quite helpful, and odds they have a replacement accu or other means to get you the data out of that phone (data cable to PC, e.g.).

--
Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.
Reply to
Hans-Bernhard Broeker

Actual all Li-Ion batteries monitor individual cell voltages. And Yes they should protect them selves from high charge voltage. But when they go wrong, they burn like a roman candle.

Reply to
Neil

To the sim. My contacts are in the phone because that is what the phone defaults to and as I've not had to move a sim between phones in this way before, I had no idea I would lose my contacts in this way.

It's an odd phone with a non-standard battery. The phone shops don't carry this particular one.

But as I said when I started, I don't believe that the fault is in the battery so replacing it won't help (unless they come fully charged - very unlikely).

The phone will not turn on without the battery. It turns itself off as soon as you plug in the charger (which it isn't supposed to do, which is why I think that the phone is at fault).

tim

Reply to
tim

What is considered a high chrge voltage in this context?

tim

Reply to
tim

In article , tim writes

Tim,

What is the old phone? btw What is the new phone?

Take the battery out of the phone. put the sim in plug the phone into it's charger (without the battery) With any luck the phone should power up. Then you can copy the numbers to the sim or write them down.

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Reply to
Chris Hills

It's a phone made by a previous (and potentially future) client. I'd rather not advertise the fact that their battery management software is pants. (more to the point I'd rather not advertise that I found these faults in a few days of use but the company's testing did not).

It's a Sagem something or other that I got for 20 quid in the Vodafone shop. Not that it makes any difference.

Nope. I do know that I can power it directly from a power supply. But as SW engineer I don't have one in my cupboard (and am between asignments so can't cadge one from the current client). I guess that I can power it directly from the charger but it might not provide the correct current

Thanks anyway

tim

Reply to
tim

12 Volts would do it. But if you want to risk it. I assume you have a volt meter. You cell phone battery should be 4.2 volts at full charge (maybe 8.4V) The Charger will be current limited. So connect it, Making sure the polarity is correct. Make sure the charge voltage stays below say 4.0 volts. The battery should pick up a charge very fast at the beginning. You should only need maybe 10 minutes to get a reasonable charge. Be careful, if it warms up fast stop charging.
Reply to
Neil

In article , tim writes

OK. I understand but that rather limits any help to generic stuff.

They are probably only 5 GBP from the local market :-)

Does it matter at this point if al you want to do is recover the numbers?

You're not in Birmingham are you?

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\/\/\/\/\ Chris Hills  Staffs  England     /\/\/\/\/
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Reply to
Chris Hills

I appreciate this, but I'm not completely inexperienced on the subject, I'm just know SFA about how the batteries are charged electrically.

Can't say that I've ever seen such things in the local market.

I don't really want to blow up the phone. I might get an opportunity to have it fixed.

Er, no. But I could be if there are people recruiting right now :-).

tim

Reply to
tim

It's nominally 3.7. The charger is rated the same.

OK so 10 minutes in the garden then :-(.

I might try this later

Thanks

tim

Reply to
tim

Nominal is the mid-point voltage Full charge is 4.1V to 4.3V depending on the cells. (4.2 is the most common.

Reply to
Neil

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