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laptop battery repair/recovery

By eddyins ·
i have 5 dell pn 5081p batteries for cp laptops which will not hold any charge is there any way they can be rocovered or repaired at an economic cost

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by TheChas In reply to laptop battery repair/rec ...

Realistically, no.

Any repair involves replacing the individual cells in the battery pack. Most companies that rebuild battery packs replace all of the cells rather than just the ones that test bad as the others are apt to fail at any time.

To rejuvenate the bad cells does require disassembling the battery pack so that each individual cell can be accessed. While rejuvenation could extend the working life of older style Ni-Cad batteries it does not work well on newer Ni-Cads and can cause other batteries to explode.

Some battery stores offer "back to school" specials on replacement batteries and will usually take the old battery packs in as cores.


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by mjd420nova In reply to laptop battery repair/rec ...

Lacking the technical skills, your best bet would be to just replace it. If you do have the skills, disassembly and close inspection my reveal what's wrong. Inspect each cell for leakage, cracks or bulging. A digital voltmeter should be used and close attention paid to voltages. They should read 1.2 volts maybe a little below, and polarity is important. A sign of cell failure is a low voltage or reversed polarity. This can cause the other cells to discharge quickly into the bad cell, and buck any charging voltages. Fully charges cells will only show about 1.25 to 1.28 volts, that's why a digital meter is essential. When I repair a pack, i will usually replace all the cells. Look closely at the voltage and MAH ratings on the cells. I will usually select replacements with the same physical size (naturally) but with a higher MAH rating if they are available. This will give you longer usage life, but may take longer to charge.

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by robo_dev In reply to laptop battery repair/rec ...

I have tried rebuilding them THEORY it makes sense.

There are just faulty cells, so you solder in some new ones, right??

Hello Reality:

These battery packs have memory, firmware, and circuitry which are heat and ESD (static) sensitive. I killed one IBM pack with too much soldering iron temperature.

In some cases the fault of the battery pack is the controller, sensor, or firmware, so replacing cells does not help (and sometimes doing a 'reset' of the battery firmware/controller actually 'fixes' the battery pack).

The battery cases are often ultrasonic-welded plastic. They are a pain to take apart, and glue/tape reassembly just does not go well.

Spotting the bad cells: Sometimes rechargeable cells look all happy at the right voltage, but the problem is that they cannot hold the charge over time. So testing with a DMM may lead you to think it's a good cell, but put a load on it and watch how fast it loses charge...that's the real test.

Finally, these newer lithium-ion and other batteries are pretty scary if you've ever seen one explode and burn, so treat them with respect.

The bottom line: buy a new battery pack and recycle the old one.

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