What Is The Difference Between NiCd vs. NiMH Batteries?

NiCd and NiMH batteries are two of the most popular battery choices we have on the market today because they have been tried and tested by years and years of use. However, which one between them is the right for you? What is the difference between NiCd and NiMH batteries?

The main difference between NiCd and NiMH is that NiMH batteries have a higher capacity than their NiCd counterparts. NiMH batteries will be able to last longer when powering different electronic devices. NiMH batteries are also better for the environment and don’t come with the same full-charge loss that NiCd batteries have.

While NiMH batteries are generally looked at as the better options for most people who use batteries, there are also some good reasons why you would want to choose NiCd batteries instead. That’s why we have come up with an article that will best explain to you the major differences between these two batteries so that you can come up with a sound decision yourself.

NiCd Batteries Information

NiCd or Nickel-Cadium batteries are actually the oldest types of batteries we have today but they are still widely used all over the world particularly because of how resilient they are especially when you are using them in the middle of tough situations and conditions that the other batteries might not be able to last through. They were invented back in 1899 but have seen a drastic growth ever since without losing touch with their roots.

One of the main reasons why NiCd batteries are still very popular today is that they are very resilient. They will be able to handle impact and falls better than their NiMH counterparts. You can also use them in extreme weather conditions. As such, if you happen to be in the middle of tough situations outdoors, NiCd batteries might be the better choice for you.

Another reason why NiCd batteries are still widely used is the fact that they are relatively inexpensive compared to their newer counterparts. They also have a long cycle life of about 1,000 charges. That means that they will be able to last for a long time before you should decide to retire them.

Here are some of the other interesting benefits of using NiCd batteries:

• The relatively acceptable maximum discharge of 20% of their original life
• High memory. So they will not degrade quickly over time.
• Very durable and resilient. Makes them great options for harsh climates.
• Quick charging times

NiMH Batteries Information

Nickel-Metal Hydride or NiMH batteries are regarded as the improved versions of their older NiCd. The reason is that they built on the ground that the NiCd stood on and began improving the weaknesses of the older generation of batteries. 

That is why NiMH batteries tend to have higher capacities and are generally going to power your devices longer. These batteries were completed in 1987 and later on became available to the market nearly a hundred years since the NiCd were invented. 

However, you have to understand that NiMH batteries do have some setbacks despite being more powerful. They are quite sensitive to extreme weather conditions and are not as hardy and as resilient as most other batteries out there. Still, if you value power over any other factor, NiMH batteries should give other batteries a run for their money.

Here are some of the key benefits of using NiMH batteries:

• Capacity is higher than most other types of batteries
• Has a high resistance to overcharging
• Also has a high resistance against over-discharging
• Comes without any corrosive or hazardous chemicals that can easily harm the environment
• Made to be lighter in terms of build. This allows them to be better options for portable devices
• Charges quicker than other battery chemistries

What Is The Difference Between NiCd vs. NiMH Batteries?

Here is a quick summary of the differences between NiCD and NiMH batteries:

Of course, these are generalizations across the battery chemistries. The actual specifications vary depending on battery size. There are dozens of different battery sizes. The most common for NiCd and NiMH are AA and AAA.

Energy Density Of NiMH And NiCd Chemistry

Energy density in a battery measures how much energy a battery contains. In that regard, the NiMH battery trumps the NiCd by a mile as there are some cases wherein NiMH batteries can have nearly three times that of the energy of the usual NiCd. In most cases, NiMH batteries are about two to three times more energy-dense than their NiCd counterparts.

That means that NiMH are actually the more powerful of the two in terms of how long they can power your devices considering that their energy densities are always going to be higher than that of their NiCd counterparts.

Load Current For NiMH And NiCd Batteries

The C-rate in load current measures how long a battery can be discharged in relation to its capacity. So, if a battery has a 2C rate, that means that it can discharge its battery in two hours at its best.

In this case, the load rates of NiMH batteries are much more consistent in the sense that they have a C-rate that’s usually under .05C at their best but a maximum of 5C. In relation to that, NiCd batteries have a max of 20C and their best is usually somewhere near 1C. This also means that it is faster to discharge NiMH batteries compared to NiCd batteries.

Internal Resistance Of NiMH And NiCd Chemistry

A battery’s internal resistance is measured in Ohms and they refer to the heat generated by the batteries due to the resistance offered by the batteries themselves. If the battery has a high resistance, it will easily heat up. Meanwhile, batteries with lower internal resistance are less likely to heat up.

In that sense, this is where usage matters when it comes to the difference between NiCd and NiMH. NiCd have lower internal resistance and are better suited for high-powered tools due to how they are less likely to heat up. Meanwhile, digital devices are much better when using NiMH batteries because they only drain the batteries moderately instead of draining them fast enough to the point that enough heat is generated.

Cycle Life Of NiMH And NiCd Batteries

Cycle life refers to how many times you can charge or discharge the battery. While NiCd may have lower capacities in terms of their energy and power, they enjoy the luxury of having a higher cycle life compared to NiMH batteries. As such, they even things out here as they may last equally long when you factor in their cycle lives and how dense they are in terms of their energy capacities.

Maintenance For Rechargeable Batteries

Maintenance in batteries refers to how often you should discharge the batteries before you can safely charge them up again to full capacity. In this case, NiMH batteries are less likely to require constant maintenance because you can safely use them for up to 90 days without fully discharging them as opposed to NiCd, which requires to be maintained more frequently but not really too often as well.

Average Cost Of NiMH And NiCd Batteries

NiCd are cheaper compared to their NiMH counterparts but the costs don’t really have a lot of differences because NiMH aren’t that more expensive. And if you factor in the fact that NiMH batteries tend to last longer in one single charge, they may be the more cost-effective of the two choices. 

So, economically speaking, NiMH batteries might the better choice in the long run even though they may be a bit more expensive than their older NiCd cousins.

Environmental Hazards

NiCd contain a lot of corrosive substances and can easily harm the environment when they are not disposed of correctly. However, on the other hand, NiMH batteries are friendlier to the environment and will not harm it nearly as much as NiCd batteries do. 

So, if you are cautious about your own carbon footprint, it might be better for you to choose the more environmentally-friendly NiMH batteries compared to the more corrosive and more toxic NiCd.

Durability Of These Batteries

As mentioned, NiCd are much more durable and are more capable of handling really hot or really cold environments due to how low their internal resistance is. That means that they are better suited for the outdoors on top of how they are able to resist impact more than their NiMH counterparts, who cannot handle extreme weather conditions nearly as well as NiCd can. So, for outdoor enthusiasts, NiCd might be better choices due to how hardy, resilient, and durable they are.

Can You Use A NiMH Battery Instead Of NiCd?

To some extent, you can replace NiCd batteries with the more powerful and more advanced NiMH batteries. However, that is not always the case because there are some instances wherein the power requirements are different. It is more important to match the energy requirements than to provide a specific battery chemistry.

One such factor to look at is their internal resistance. Because NiCd are much better-suited for tools and equipment that require a spike of power in an instant, it might be too difficult to use a NiMH battery in their place because these batteries are quicker to heat up and are much better used for devices that use moderate power at a moderate pace.

As to appliances – for appliances that do not carry their own charging functions – you can easily replace NiCd with NiMH. But you cannot use them both at the same time because of how they have different discharge rates and characteristics. 

On the other hand, appliances with their own charging functions for NiCd cannot handle NiMH because of how the NiMH will end up degenerating faster when you are charging them in the conditions that are better-suited for NiCd batteries.

Further Reading

Read our review on the best rechargeable solar light batteries.

Learn where solar power goes when batteries are full.

Check out our guide on how to replace batteries in solar lights.