There are too many different battery chemistries to cover them all here, but I will cover the most popular types and some of their pros and cons. Let’s start off by explaining the basics on each type of battery, and once that is established we can start to compare and contrast the differences between them and their use cases.
Alkaline Batteries
By far the most popular battery type or chemistry is the alkaline battery. These are the “standard” ones you grew up with, and can buy at the store to power a lot of things in your house. Smoke detectors, flashlights, toys, etc. Alkaline batteries are a consumable (single- use) item. Once they are drained, they are trash. You cannot (and should not attempt to) recharge them. The advantages of alkaline batteries are that they sell them almost everywhere, they are generally less expensive when compared to other battery chemistries, they generally have a higher voltage output and last longer than some other rechargeable batteries of the same size/type. Using a standard AA battery as an example, a standard alkaline AA battery puts out 1.5 volts, and around 1,500 to 3,000 mAh (milliampere-hours) of current. These batteries will give a consistent output of power until they get close to being fully drained, at which point they will start to taper off until they no longer power whatever they are in. For AA batteries, this is generally at less than 1 volt per cell.
Nickel Cadmium (Ni-Cd) Batteries
One of the first commercially available rechargeable battery chemistries for home use was the Ni-Cd (pronounced Nigh Cad). These batteries would output 1.2 volts with an approximate 800 – 1,000 mAH rating. They could develop a memory-state if used for short durations and then recharged without fully discharging first. This would shorten their discharge time to whatever interval was being used the most. This effect was reversible, but it was an issue to be considered. Ni-Cd batteries have been replaced these days with NiMH batteries for many reasons, but mainly due to the lower cost of NiMH batteries and the fact that NiMH batteries contained fewer toxic chemicals.
Nickel-Metal Hydride (NiMH) Batteries
Next up are the nickel–metal hydride (abbreviated as NiMH or Ni–MH) batteries. Using the AA as a basis for comparison, a standard NiMH battery produces 1.2 volts and around 2100 mAH of current. Since some devices will stop operating when a battery drops below 1 volt, you don’t have as much headroom with a NiMH battery, however, a NiMH battery has a slower voltage drop than an Alkaline battery, giving the NiMH battery a similar runtime. Another huge benefit to NiMH batteries is that they are less prone to leaking corrosive electrolytes than alkaline batteries. If you’ve ever had something ruined by a leaky battery, you will know how much this feature is worth. However, the most attractive reason to use NiMH batteries is that they can be recharged and reused thousands of times. Also, with NiMH batteries, you do not have to worry about a memory state. You can recharge them at any discharge level and it will not cause them to have a shorter discharge time.
Lead-Acid Batteries
Lead Acid batteries can be found in most automobiles, riding lawn mowers, motorized toys for kids, and emergency lights. Lead Acid batteries come in 2 main types, Sealed Lead Acid (SLA) or Valve Regulated Lead Acid (VRLA). Lead Acid batteries are rechargeable. These batteries are used the most where a high current rating is needed, and where they will be used for shorter durations before being recharged. Unless they are rated for deep cycle (like most marine batteries) you should not allow them to fall below a depth of discharge (DOD) rate of 50%, with 20 – 40% being the recommended depth of discharge from most manufacturers. A lower depth of discharge (below 50%) can hurt the cycle life of the battery, or ruin it completely, especially if the battery is allowed to remain in a drained state for long periods of time.
Lithium Ion (Li-Ion) Batteries
Many, but not all, Lithium Ion batteries are rechargeable. Li-Ion batteries have a lot of advantages to their counterparts. They have a high energy density, which means they fit more power in a smaller area or in a lighter weight. They are generally much lighter than most other battery types, and have a long lifespan allowing them to be recharged thousands of times with no danger of a “memory effect”. They can be recharged faster than other battery types, and have a low self-discharge, meaning they hold a charge longer when being stored than other types of batteries. Some of the disadvantages of Lithium Ion batteries are that they can be a fire or even an explosion hazard since they have flammable electrolytes, and they contain chemicals that make them more expensive than other types.
Lithium Iron Phosphate (LiFePO4) Batteries
In the process of being written as of 2025-09-12