Why Lithium-ion?

The latest technological advances in rechargeable batteries for power tools is Lithium-ion as it has one of the best energy density’s making it lighter and more compact. Here we will take a look at the reasons why Li-ion is being used for cordless power tools.

So it is lighter and what else you may ask? It does not seem to suffer from the so-called “memory effect” or slow loss of charge when not in use.

“Memory effect” is a problem with Ni-Cad batteries whereby they allegedly kind of forget how much charge they can take, making them work less and less efficiently as time goes on or each time it is charged!

Li-ion batteries will keep charging no matter what stage they are at when you put them into the charger and will do so until completely charged, hence no excuse for failing slowly during its life time!

A Li-ion battery charges faster and some make claims of being able to charge up to 2000 times, look for features such as optimum charging.


  • There is less need to worry about your tool losing power by self-discharging if you leave it alone for a couple of weeks.
  • A lithium-ion battery will only discharge around 5 – 10% of its charge over the period of a month compared to 30% for other rechargeable battery types.
  • So no more extended tea breaks while you wait for your tools to catch up!
  • Great news whether you are a DIY enthusiast or a professional carpenter
  • Keeping the battery at 40% charge in a cool place will extend its life but do check this with the manual

For several options on Lithium-ion battery operated tools look here.



An 18V Lithium-ion battery weighs about the same as 12V Ni-MH battery, so they are lighter.

  • Once again, it doesn’t matter if you are looking at DIY jobs around the home or carrying out the first fix on a roof, the newer batteries are lighter and easier on the hands, wrists, arms, shoulders and backs!
  • So there is less chance of injury or repetitive strain and that has to be a good thing
  • And you can speed up a bit as well, carrying less weight
  • Especially good if you are having to use your tools above shoulder height


Hot and cold

  • Batteries do not like heat so now manufacturers are designing batteries that keep cool
  • Look for warranties of 3 years now, hopefully soon to be an industry standard for rechargeable batteries
  • Some will even come with fan operated chargers so they can be charged up quickly and kept cool at the same time


Another industry standard seems to be 5Ah giving a much longer running time for the battery this combined with 18V of power making them far easier to use than corded tools.  No more wires running all over the place, no more need for extension cables.

Some disadvantages

  • They cost around 40% more than other types of battery
  • Transportation of materials is restricted, so shipments of large quantities may be subject to regulatory control, so depending on the amount of lithium it may be considered a “Class 9 miscellaneous hazardous material”
  • There is still more to come, more research with different metals and chemicals being tested but this may true of all advances in technology including infrared, ceramic use, ionic technology, computerized energy, it is all a never ending story


This term “memory effect” may not exist, or it may be true, however even NiCad batteries have come a long way and this term may not mean anything.  The general consensus is to recharge your battery when it starts to fail rather than trying to wait for it to discharge. It is difficult to know the truth of the matter so the best bet is to always check your instruction manual.


It may be easier in future to buy a complete set of tools with just two batteries, as they are becoming so efficient.  Perhaps investing in several different tools with one pair of batteries for all the jobs would be more prudent than having corded gadgets and various different types of battery.

For anyone who is slightly obsessive about their tools and wants to keep it all neat then that has to be available. Being able to pick up the right tool for the job is also imperative when a job needs to be finished.

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