Batteries 101

By now everyone has heard of Lithium-Ion batteries, but there still seems to be plenty of confusion in the market. Is Lithium-Ion really better than the Ni-Cad and Ni-MH batteries we have been using for the last 20+ years? Let me assure you that Lithium-Ion batteries are engineered with far superior technology. But in order to appreciate the extent of this technology, you will need to forget some of what you’ve already learned about batteries.

To start, let’s back up. Ni-Cad batteries were the technology of the 70’s and 80’s. These batteries provided adequate power, but due to their chemical composition they are heavier and bulkier and have a shorter overall cycle life over their lifetime. Much of this is attributed to the “memory” in Ni-Cad batteries. When a Ni-Cad battery is placed on a charger without being properly drained or removed from a charger without being properly charged, it creates a “memory.” This is essentially a point on the battery that when recharging in the future it will not surpass, eventually making the battery only capable of holding half a charge and sometimes less.

At this point it’s important to clarify proper Ni-Cad charging and use: a battery should never be completely drained since this can damage the cells. A battery should always be charged when you notice a decrease in performance. For example, if you have drilled 100 holes and they only take 2 or 3 seconds each, and then hole number 101 takes 4 or 5 seconds, that is clearly a decrease in performance and an indicator that it’s time to charge the battery. You should not continue to use it until it will not drill at all, and NEVER tape the trigger down to allow the tool to run until it cannot run any more. Furthermore, you should never charge a Ni-Cad battery while it is hot. After using it strenuously for several hours, a battery can heat up. Heat is the number one killer of batteries. Always allow the battery to cool before placing it on the charger. Finally, never pull a battery off the charger until it has completed the charging cycle. If you follow these simple steps your Ni-Cad batteries will last much longer.

Now for Lithium-Ion. Some of the basic battery principles still apply. Heat is a also an enemy of Lithium-Ion batteries, but an advanced charging system like Makita’s, for example, actually has a computer chip inside the battery and a built-in cooling fan inside the charger. Therefore, while other Ni-Cad batteries may take several hours to cool before they can be placed on the charger, but some, like the Makita 18V Lithium-Ion system actually starts cooling the battery immediately once it is placed on the charger with its built-in cooling fan. This allows Makita 18V Lithium-Ion batteries to boast the fastest recharge times in the entire power tool industry. The Makita 18V LXT battery (part # BL1830) will charge in 30 minutes and the 18V Compact battery (part # BL1815) charges in only 15 minutes. That is four times faster than traditional 18V Ni-Cad batteries.

Lithium-Ion batteries have some major advantages over the Ni-Cads of yester-year. They are much lighter than their older counterparts and much smaller too, yet they pack the same power. The new chemistry and technology in these batteries will now hold a charge for months and even years while sitting idle on a workshop shelf waiting for their next use, instead of depleting their charge, so you can be confident when you are ready to work, your tool is too. Ni-Cads have a slow drop in power when reaching the end of their charge, sometimes giving the appearance of having a charge, only to get to the top of a ladder and realize that there was nothing left. The Lithium Ion batteries of today hold essentially 100% performance through the entire charge and then quit completely when they run out. This leaves no question of whether the battery is ready to be charged, or if you should try to run a few more screws.

Lithium-Ion batteries do not have “memory,” but you should still follow these basic guidelines during use. Do not over-discharge the battery before recharging. This means that once you notice a decrease in performance, place it on the charger. While it will not hurt a Lithium-Ion battery to sit on the charger until it is time to use it, it is not required to do this to have a charge when you are ready like you probably experienced with your older Ni-Cads. Once you have charged the battery, you can be sure it will be ready to go when you are, so remove it from the charger and be confident in the superior technology you have purchased.

I hope this helps to clear up some of the confusion over the new battery chemistry and technology, but if you still have any questions, feel free to ask them in the comments below.

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