HP IPAQ Charging problem

[shack]

Hi folks I was given my F-I-L's old PDA and worked fine charging from both mains and car charger, but has just slowly run out of juice and won't take anything from either source now. I'm not a battery Guru, but is the most likely issue a now defunct battery? it had been fine and is out of the blue so to speak (it's a funny one and wouldn't know where to start checking it) Replacement ones are about £15 so checking you you helpful folks first.
I only tend to use it for the Tom Tom plug in bits, and would miss it if it went. The battery is a good 3 years old I'd guess. Thanks in advance

[Lumiya]

Even if the battery was defunct it should still work via the PSU.. You sure the PSU isn't faulty? If not then you probably have a problem with the internal power regulator..

[pete h]

How safe it is I don't know but I've frequently used an old bike optimate to re optimise batteries from electronic devices, it's one that lets me switch between 6v and 12v output.

I use the crocodile connectors with paper clips inserted and rubber banded to the offending battery terminals.

I fully expect to be told that I've narrowly avoided being blown up.
But I've got a 50% success rate on recovering batteries.

[Lumiya]

Very much depends on the battery..

If it's nicad or NiMH and either 5 or ten cell then yes you can use the optimate..

But any other voltage/cell-count and you might end up destroying the battery..

Also remember that most 1.2v cells (nicad/NiMH) require about 1.48v to charge them which again is fine, but Lithium ion batteries and other newer batteries require different charge voltages..

[jarl]

but Lithium ion batteries and other newer batteries require different charge voltages..

Just thought I'd clear this up. You HAVE to charge a lithium cell by cc/cv. What this means is that for the first stage you use cc- constant current. Select a limit for the current (1 amp is ballpark, normally about a third of the capacity of the battery), and then let the voltage do whatever it wants to maintain that amount of current passing into the battery. Then the cell switches to CV (constant voltage) and holds the voltage at 4.20V until very little current passes into the cell- then the cell is charged. Increase the CC rate, then the CV bit takes longer to complete, so min. charge time of a lithium ion from empty is always about 2.5 to 3 hours. Unless you've got a new fangled chemistry.....


But yeah, that's a long fangled way of saying "only use a li-ion charger on a li-ion battery even if the voltages are the same".

[Lumiya]

You never heard of the KISS method as I think only me will understand you

[BobA]

How safe it is I don't know but I've frequently used an old bike optimate to re optimise batteries from electronic devices, it's one that lets me switch between 6v and 12v output.

I use the crocodile connectors with paper clips inserted and rubber banded to the offending battery terminals.

I fully expect to be told that I've narrowly avoided being blown up.
But I've got a 50% success rate on recovering batteries.

A small tip!


Don't be tempted to try it with Lipo (Lithium Polymer) batteries unless you want to kiss your house and sweet a$$ goodbye!!!!!!!


http://www.rchelisite.com/lipo_batte...fety_guide.php

[shack]

Wow thats a lot of info in a very short space of time.

I've plopped the battery out and its a small flat rectangular one with recessed teminals (so no hope for croc clips with whatever the rate of charge) it's a rechargable Lithium-ion with a 3.7v 900mAh rating (?)
As I said it worked fine getting charged a few weeks ago, and hasn't been dropped or gotten wet or any of the usual expected unfortunates.

If it is the PSU (?) would that be easy (cheap) to check, if not is it worth a £15 new batt gamble (I have a lot more exciting things I'd rather the money go on)

Thanks again for helping an electronic beginner

[Lumiya]

PSU's can be tested with a simple multimeter.. You can though use a small bulb (the PSU's are normally 5v so see if it'll power a 6v bulb) (the actual voltage is printed on the side of each PSU)

[jarl]

A small tip!


Don't be tempted to try it with Lipo (Lithium Polymer) batteries unless you want to kiss your house and sweet a$$ goodbye!!!!!!!


http://www.rchelisite.com/lipo_batte...fety_guide.php

Lipo's are fine. The problems people have is either overcharging or abusing them- they're so light they're frequently used in RC cars or planes, which, in competition use need to be recharged quickly, be as small as possible, and as such get discharged quickly. So it's no surprise that every now and then one of these abused cells will vent with flame. Under normal use as in a PDA it will be fine.