The lifeblood of the cordless drill is the battery. Sooner or later the battery will not hold the charge anymore because of the frequent usage. Are you looking for a replacement battery or charger? You can find them right here by clicking on a brand name (Dewalt, Makita, etc.) either on the top or on the righthand side, under the Online Deals heading. Here's some basics about the battery itself.
Our experience of how well a tool performs is directly related to the quality of the battery.
There are 2 parts to the batter power: 1) voltage, and 2) amp-hour. There's also 3) the battery type, which is about its internal charge-storing chemistry.
VOLTAGE (volt or v)
Voltage is the electrical pressure that pushes the motor to rotate. The higher the voltage from the battery, the more the torque can come out of the motor, which enables it to perform heavy-duty projects. Therefore, to consider how much power we need, we look at the voltage.
The voltage can range from 2.4v to 36v on a cordless drill. The impact driver goes from about 9v to 18v. Here is a list of voltage span vs. project application, based on the voltage of a cordless drill.
| Size | Voltage | Project Application |
|---|---|---|
| Compact, Pocket | 2.4v, 3.6V, 4V, 6v, 7.2v, 9.6v, 10.8v | Light-Duty, Electronics, Computers. |
| Regular | 12v, 14.4v, 15.6v | Electrical, Plumbing, Household Projects, Carpentry. |
| Large | 18v, 19.2v, 24v, 36v | Storage Shed, Tree House, Playground Structure. The 24v & 36v are specially suited for masonry or heavy construction projects. |
AMP-HOUR (Ah)
Amp-hour is the charge-holding capacity of the battery. The greater the amp-hour, the longer-lasting the battery is. Amp, or ampere, is the measurement of electric current. Hour is the measurement of time. Together they make up the charge storage capacity. For example, a 3 Ah (amp-hour) battery can supply 2 amps of current for 1.5 hours, or 1 amp for 3 hours.
Typical Battery Capacities
Compact Size Drill: 1.0Ah
Regular, General-Purpose Drill: 1.0Ah to 2.5Ah
Heavy Duty Drill: 2.0Ah to 3.5Ah.
BATTERY TYPE
The charge storage technology of a battery is based on the chemical elements inside. The storage technology consequently affects its weight, packaging, charge-holding capacity, and toxicity towards the environment. The cordless drill batteries have 3 kinds of chemistry: Ni-Cad, Ni-MH, Li-ion.
Ni-Cad, Ni-Cd, or Nickel Cadmium, battery is the cheapest and earliest technology of the three. Many cordless tools employ this type of battery because of the low cost. But cadmium is a heavy metal and is toxic. The spent battery of this type must be properly disposed.
Ni-Mh, or Nickel Metal hydride, battery is the second generation technology after the Ni-Cd. It improves upon Ni-Cd in that it holds more charge, and is less toxic than Ni-Cd for waste disposal. It's a more sensible choice despite its higher price.
Li, or Li-ion, or Lithium-ion, battery is the latest state-of-the-art technology. The main advantage is that, volt for volt, Ah for Ah, it weighs much less than the other sorts of batteries. It's broadly available and gaining in popularity.
In general, the weight of a battery is propotional to the voltage and amp-hour. Higher voltage and/or higher amp-hour in a battery will command a higher price, as well as feel more substantial. The weight of a battery is not always a good thing. Light-weight Li battery is very welcome to the people who have used them.
Battery Charger
The batteries must be recharged on a charger. The chargers go by voltage levels. A 9V battery can't be recharged on a 18V charger, or other voltage level charger. This restriction is less of a problem now that there are universal chargers available. To be sure, double check the charger's compatibility chart. Another thing, an 18V Ni-Cd battery and an 18V Li battery can't use the same charger, because they are physically packaged differently.
Battery chargers have improved quite a bit in the past years. The new models have smart circuits built in that prevent overcharge or damage of the battery. The one-hour quick charge is a specially nice feature. With that a person can practically work with a cordless drill tool non-stop on any project, as long as he has two good batteries.
Power Requirement
How much power should we look for when buying a new cordless drill? What information of the battery can tell us whether it has enough power or not? Well, the answer is not just numbers. It lies in what you will use it for. The project should be the first consideration. Because neither too much nor too little power is good. After you have determined the scope of the job, then check the cordless tool's torque rating, and decide if it is the proper match.
Torque is how strong the motor turns. Torque is expressed in inch-pound or foot-pound. The Dewalt cordless drills use a completely different unit. A rule of thumb is that similarly-priced tools have similar torque output. So that comparing different torque units can be done by looking at the prices. Tools with small torque rating can be a good thing. It means the tool will be light weight and small and easy to work with. Tools with high torque ratings usually have a clutch that allows you to adjust the torque output up and down. If you want extremely high torque output, look for impact drivers. They are torque beasts.
