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Dead Nicd Battery Repair & Recondition
Can you imagine the chaos that would ensue if you were unable to recharge your laptop, your mobile phone of any of the portable electronic devices so ubiquitous today? That is a situation you wouldn’t want to be in even in your worst nightmares. But have you ever wondered about the rechargeable battery in these devices – which battery is used? What are its drawbacks or advantages in comparison to other standard batteries?
Well, let’s start at the very beginning. Nickel- Cadmium (NiCad) is the most popular rechargeable battery technology used in almost all the portable electronic devices. They are so popular because they are relatively cheap, come in various sizes and are easy to store. But these batteries are plagued by “Memory Effect,” a phenomenon associated with rechargeable batteries.
What are NiCad Batteries?
NiCad batteries are made of Nickel in the form of Nickel hydroxide and Cadmium suspended in a potassium hydroxide solution. These batteries maintain a steady voltage of 1.2v per cell right up till the very end before the charge is completely depleted.
This is an advantage because you can use your device for a longer time.They have very low internal resistancewhich ensures that they recharge fast and also discharge quickly. That is one more reason for their immense popularity in the rechargeable batteries scene.
What is “Memory Effect?”
This is an issue especially with NiCad batteries wherein over time a battery tends to lose its charge faster than when it was new. Here, though the battery is charged let’s assume 60%, the display will appear as 100% charged; as a result when the battery is used in a gadget, the charge doesn’t last long. Overcharging of NiCad batteries is one of the causes for this phenomenon.
In variably you can overcome the memory effect by subjecting the battery to several rounds of complete discharge before it can be recharged again. A discharge cycle also known as an exercise should be done at least once every 1-3 months. But, this process will eventually reduce the life of the battery.
When should NiCad batteries be repaired?
The memory effect is one of the main reasons for repairing Nickel Cadmium batteries to increase the life span of the batteries. These batteries also display high levels of self-discharge when stored, needing recharging.
How to revive dead NiCad Batteries?
These rechargeable batteries do not die in the true sense of the word. Due to overcharging, memory effect, over exposure to high temperature and self-discharge sulfur crystals form inside the cells gradually reaching the battery terminals and preventing the cells from getting recharged.
But, thankfully by passing a high voltage current through these dead batteries you can revive them and they will be as good as new. Reconditioning is another method to get rid of stubborn sulfur crystals.
Basically you need a DC power supply. People use car batteries too revive dead NiCad batteries but this is not safe and the uninitiated should definitely not try it. Remember cadmium is toxic and when the batteries are subject to high electricity the risk of explosion is high.
The simplest way to repair is to use a capacitor because you can get a quick high voltage discharge from them. The most common capacitor used is from a disposable camera. Charge the capacitor to a voltage which is approximately 2-4 times the voltage of the cell. Now connect the battery to the capacitor with the same polarities together.
Thus once the pulse charge is passed through the battery the Sulphur crystals are destroyed and the cell is ready to be recharged again. Regular exercising and reconditioning will maintain the health of the nickel cadmium batter.
