Which Battery Type Is Best?

Rechargeable batteries come in 3 major types.

By knowing the advantages and disadvantages of each kind of cordless tool battery, you can more effectively purchase tools that best fit your needs.

Below is a list of the different common types of rechargable batteries that are used in battery powered tools.

         

          Nickel Cadmium -  Ni-Cd:

Found commonly in household batteries such as AA, AAA, 9v, etc.

The "Ni-Cd" is the mother of all batteries typically used for a cordless power tool.

Pros:

• This type of battery holds a charge longer than other types, but, they don't typically have the voltage that is needed to power todays tools and electronic devices as well as it's predecessor, the NiMh battery did.
• NiCd batteries are less expensive then other alternatives and these batteries have proven to be fairly well suited for cold weather .
• Usually charged with very high currents so a fast charge does little or no damage to the battery.
• Has more life cycles than Ni-MH (400-1000x).
• Does well in cold temperatures (less than 20F).

Cons:

• Has high self-discharge rate.
• Suffer from ‘memory effect.
• Must be discharged before stored.
• They are also larger and heavier then the next generation of Ni-Mh batteries 

 Nickel Metal Hidride  - Ni-Mh

Also found in common household batteries just as the NiCd batteries, 
They produce a much higher  voltage output for electronics with the trade off of having a quicker power drainage.

These batteries were originally introduced as a more environmentally friendly and powerful battery option.. 

Pros:

• 2X the capacity to equivalent size Ni-Cad.
• Better run time and lighter than Ni-Cad.

Cons:

• The design of the NiMh battery leads to greater internal resistance and it's associated heat generation.
• This heat generation is why chargers for the Ni-Mh batteries include fans to keep the batteries from overheating.
• Heat causes the Ni-Mi batteries to survive less re-charges and thus offer a shorter life cycle.
• The higher amperage, lower weight and smaller size of the typical NiMh battery is offset by its shorter life cycle and thus higher cost. (500x)
• The Ni-Mh batteries don't do as well in cold weather either as the Ni-Cd batteries, so the Ni-Cd batteries are usually chosen when expected to be used in cold climates. 
• Cannot be rapid charged without shortening lifespan. 
• Because it has the highest self-discharge rate, it should be charged before storing.

 Lithium Ion - Li-ion:

This is the newest battery that is promising to overshadow the use of all that have come before.

Unfortunately, they have a more complex make-up so  they  don't come in standard household sizes like the AA & AAA type batteries.

These batteries are used in all battery operated hand tools as well as laptops, cell phones, iPods, iPhones, etc.  These batteries have a long lasting energy drain and don't discharge as quickly while sitting idle.  

  

Pros:

• Lightest weight of the 3 major types.
• Excellant run time.
• Lower self-discharge rate.
• Maintain the longest runtime at the lowest temperatures.
• Highest number of recharge cycles.
• Li-ion batteries do not need to be fully discharged and recharged like the Ni-Mh and Nm-Hd
• Some newer Li-Ion batteries can be recharged in 30 minutes!

          

            Cons:

• Longer re-charge times to allow for rebalancing cell to cell differentials and more sophisticated battery chargers.
• Highest Cost
• Longest recharge time.
• May not do as well in cold weather as Ni-Cad.

In a nutshell.. 

The use of Li-Ion batteries is actually very young and is an intermediate step and still evolving with a few minor problems, like not running  or charging in very cold weather, stopping for no reason...then recharging back to full capacity in a couple of minutes, etc.

For those who occasionally use their tools, it may be best just to settle for Ni-Cad powered tools as they are harder to damage than other types and will endure deep discharges for longer periods. The Ni-Cad battery is excellent for long-term storage, and in most cases stored fully discharged. A Lithium-Ion battery, in comparison, will be permanently damaged if stored in discharged state.

For active DIY ers and professionals that use their tools on a daily basis, the Lithium-Ion battery is currently the best choice, since it has more life cycles and will provide your cordless tool with the maximum power it needs. It charges fairly quickly to keep you working for a long time before it will run out of power.