Nickel-Cadmium (NiCd) is a very well known rechargeable battery technology, used by several electronic equipments, such as laptop computers, cell phones, cordless phones, old motherboards, etc. It is also very well known by its (in)famous “memory effect”, which makes this kind of battery to lose its charge faster when it is old than when it was brand new. In this article we will be explaining more in depth how NiCd batteries work, what and why the “memory effect” happens and how to prevent it.

As the name implies, NiCd batteries are made of two chemical elements, Nickel, under the form of Nickelic Hydroxide, and Cadmium. A third element used as electrolyte, usually a solution of Potassium Hydroxide (KOH). The Cadmium is the big villain. First, it is the element behind the “memory effect”, and second it is a heavy metal and thus very toxic.

That’s why newer rechargeable battery technologies do not use Cadmium anymore (e.g., Nickel-Metal Hydride [NiMH], Lithium-Ion [Li-ion] and Lithium-Ion Polymer [Li-Pol]). Laptop computers, cell phones, cordless phones and motherboards found today on the market don’t use NiCd batteries anymore and you won’t have any kind of problem or “memory effect” if your electronic gadget uses a different battery technology from NiCd. Just to make sure, if you take a look at your battery you will find a sticker showing which battery technology it uses. If it isn’t NiCd, you won’t have the “memory effect” problem.

What is this “memory effect” anyway?

“Memory effect” is when your battery “thinks” that it is fully charged but it isn’t. So let’s say that is 70% charged but it “thinks” that it is 100% charged. Under this condition, when installed on its charger it will stop recharging, because it is thinking that it is already full. When you start using your gadget, it will last shorter, since it is only 70% charged – and thus the assumption that older NiCd batteries last less than brand new ones. Which is true, but that are ways of preventing the “memory effect” to occur.

Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.