How NiMH Batteries Work

NiMH is a rechargeable battery that is made to address operating issues found in older rechargeable batteries. In case you are not familiar with it, the name means Nickel Metal Hydride. The battery has plenty of advantages over NiCd’s and older battery types, and one of them is its memory effect bypass feature.

What is Memory Effect Anyway?
Batteries from older generations, including NiCd (nickel-cadmium), go through what is commonly called the memory effect, which can be easily demonstrated up by requiring these batteries to be fully drained before charging. Failure to drain these batteries before charging will result to reduced capacity. NiMH batteries are safe from this effect and can be charged anytime and at any point of their usage cycle.

Increased Battery Capacity
With the increasing demand for higher energy reserves, NiMH batteries are climbing up the popularity ranks fast. This is because NiMH has higher energy reserves that traditional rechargeable batteries. As a matter of fact, these new generation batteries have two to three times the capacity of a similar-sized Nickel-cadmium battery. Also, the density of its reserved energy is even comparable to that of a Li-ion battery.

Materials Used
To get a grip on How NiMH Batteries Work, it’s good to start with the materials used in making them. Just like your usual battery, NiMH has two metal strips that act as its positive and negative terminals together with an insulator placed in-between them; they are compressed and placed into a canister that contains liquid electrolyte. Now, this is where it become different from other batteries. The positive terminal is made of nickel while the opposite terminal is made of hydride, hence, the name.

Electricity Generation
When using a NiMH battery, electrons go out of the positive terminal, which then produces hydrogen. As this happens, the electrons go to the negative terminal as they absorb the hydrogen. The whole process produces electricity, which is put into reversed once that battery is put into the charger.

What Happens When NiMH Batteries Are Overcharged?
As mentioned, you won’t have to worry that much about “memory effect” with nickel metal hydride batteries but you will still have to worry about “voltage depression.” In case you haven’t heard of it, it is when a battery discharges faster than it should be. This is caused by overcharging a battery repeatedly. Repeated overcharging causes electrolyte crystals to form on the battery’s plates, which clogs the plates resulting to increased resistance and lower battery voltage.

Fortunately, voltage depression is not much of a problem. All you need to do is keep your NiMH batteries from overcharging to be able to use them at their full capacity. And since new generation NiMH cells don’t have memory effect problems, you can consider them to be low maintenance rechargeable batteries.

Trickle Charging
If you are worried about overcharging your batteries then you might want to use a trickle charger. Unlike your average battery charger, trickle chargers use low current to power up batteries. According to manufacturers, overcharging is nothing to worry about if you’re charging your NiMH at low currents. So, if you want to charge your batteries without dealing with overcharging then trickle charging is for you.

On Using Fast Chargers
When using fast chargers, you might want to be a little cautious about leaving your battery while being charged or you’d risk overcharging it. To be on the safe side, terminate the charging cycle right before the battery reaches its peak capacity. On the other hand, you can also monitor the charging process by observing the change in voltage and charging time.

Safety Feature
NiMH batteries feature a fuse installed in series with the cells the increases safety. The fuse opens up the voltage series if the current gets too high or the battery itself gets too hot. It can also be reset once activated, which can help increase usability.

Handling NiMH Batteries
If you want to increase the life of your NiMH then you should do the following:

– Avoid overcharging. Using a good charger can help you out with this.

-Store your batteries in a cool dry place. Storing batteries in hot and wet places can either decrease its capacity and lifespan or render them useless.

-Get high-quality NiMH batteries. Not all NiMH batteries are made equal; some are better than the others. High-quality NiMH batteries will give you your time and money’s worth.

If you’re looking for a battery that has great capacity, reliable energy reserve that doesn’t unexpectedly drain, and low maintenance requirement then Nickel Metal Hydride is for you. With improvements made in its newer generations, NiMH can be considered a groundbreaking rechargeable battery.

Special thanks to for your support!