Reconditioning a cell phone battery? Is it possible to restore life span?

[Kator01]

Hi Mark,

please find attached the most simple and cheap system you can get.

Before you use this make sure that the cells are not leaking. By this I mean that there is salt appearing around the positive pole. Of course you have to crack open the casing ot the battery in order to check this.

But anyway you can use the circuit attached here. Depending on the total voltage of you NiCd-battery-stack you should use the correct AC voltage at the secondary of the transformer. which is always about 3 times higher than the DC-Level of your battery-stack.
In this case for a 12 V dc level you need 30 to 45 Volt AC at the secondary. You can use 30 V AC but then you need a lower resistor in relation to using 45 V which in this circuit is limiting the current supplied to the NiCd.

NiCd can be charged 2/3 of the tortal capacity. having a 900 mAh battery you can charge with 300 mA without the battery getting hot. Usually I however do not charge higher than 200 mA.
Keep in mind to choose the correct transformer ( secondary voltage and power) which must be adapted to the power supplied to the battery.

The diode can be a standard 1N4001,... 1N4007 and it supplies only one half wave ( positive part ) of the AC.
In this way you have a controlled pulsed current entering the battery and it removes any memory-efects for sure, I can guarantee this because I have applied this hundret of times.

There are three states of condition I found with older NiCd:

1) one or more cells are shorted. If you have 3 cells in series and the middle one is shorted you can still charge the other two. At the end of or even during the charging process you will see which one is dead. just measure the total voltage in dc mode of your meter while charging.

2) One or more cells have very high resistance. in this case no current will flow which you can check with your ampere-meter.

3) one ore more cells are low in capacity and voltage. This is the condition which can be repaired.

Of course all threeeconditions might occur in combination while you charge a stack of at least 3 cells.

it really fun to watch the dc-level slowly rising up beyon 1.2 V. it can reach 1.45 V for one cell.

What type of cells can you charge with this methode ? Almost any type of rechargeable cell with two exceptions :

Li-Ion-cell and Li-polymer-cells. these must be charged with contant current.

I even reconditioned old lead and lead-gel ( dry-cells). In this case this method is only used to re-condition the cell-structure ( desuphator-function) using 50 mA, applied with the same circuit but this time you can use your mains-outlet ( 120 AC, here in Europe 230 V ) and connect the hot wire to the diode. Instead of the variable resistor you use a 10 Watt incandescance-bulb which limits the current and if the cell is shorted will just fuction as if it is grounded. If the bulb is not on then you have high voltage at the positive terminal of your lead-battery which means the cell hast very high inner resistance. in this case you just wait 20 minutes an if the bulb does not light up disconnect the circuit by pulling out the plug and have a look inside the cell.
I usually crack the drycell open ( before I hook it up to the circuit ) and carefully refill some steam-destilled water in each cell as this is the first thing you have to check. Almost all cells I saved from the dump where really "dry" in the true sense. There is no maintainance-free lead-battery. Water is split and escapes throug the build-in silicon-caps.
After the cell is reconditioned is must have 12 to 13 V dc-level. Only then it makes sense to apply the normal power-dc-charge-process which fills it up again.
Now here comes a very important step after you have reconditioned and recharged the cell - and this is true for both types :

You have to power-discharge them  into a load ( 50 Watt 12 V bulb for lead-battery ) to almost emty half the capacity and then slowly continue discharge  with 1/10 of the capacity. You can go as low as 4.5 Volt with a dry-cell and almost down to 0.5 Volt with a NiCd. Following this you must immediatly charge up in the normal way.

My experience is that I had success only with 1/3 of all cells I tried to re-animate.

Good luck

Kator01

[ramset]

Kator 01

Wow thanks

Chet

[ramset]

Any one have any tips for alkaline batteries ??

I've heard these can be recharged?[just saw a thousand or so at the dump]

Thanks

Chet

[Mark69]

Hey thanks all for the input,  I will give some of these a try.  It is a lithium ion battery.

Mark

[Paul-R]

Try the circuit on page 21. It does some good to lead acid battys.
http://www.free-energy-info.co.uk/Chapter6.pdf