Showing posts with label Batteries. Show all posts
Showing posts with label Batteries. Show all posts

Saturday, 31 December 2011

Cordless Power Tools - Batteries Are the Key

!: Cordless Power Tools - Batteries Are the Key

Batteries are the key to any cordless power tool, whether choosing a cordless drill, hedge trimmer, leaf blower, or any other type of cordless tool. Battery voltage is not the single most important factor to consider when choosing cordless power tools. With cordless tools available all the way up to 36 volts, amperage/hour, and battery type must also be taken into account. Many 14.4 volt tools will outperform 19.2 volt tools due to battery type and amp/hr rating.

Battery Rating Basics

Amperage hours and voltage are used to rate a cordless tool battery. Amperage hours are used to determine how long a battery will last and voltage refers to the flow or strength of the electrical current. As I was taught in high school shop class the theory of electrical current is easier to understand if you think of it as water being pumped through a pipe.

Voltage is used to measure the speed at which water is flowing through the pipe. Amperage represents the size of pipe that will be filled to capacity. Amperage hour rates how long the flow can be maintained or how long the battery will last.

As you can see by using this analogy the higher the voltage in conjunction with higher amp/hr the stronger the battery. Cordless power tool batteries are usually available in 1.4, 2.4, and 3.0 amp/hr. The amp/hr rating of the battery can be found on either the side or bottom of most batteries.

Battery Types

There are three types of batteries used in modern cordless power tools.

Ni - Cad ( Nickel - Cadmium ) are the oldest type used and are prone to developing a memory and early failure. Even when properly maintained they are lucky to be recharged 400 times before failure occurs. Ni -MH ( Nickel Metal Hydride ) are a newer design than Ni - Cad and can develop a memory, though not as quick. The worst issue discovered with this type of battery, the higher the amp/hr rating, the fewer charge cycles before battery failure occurs. Li - Ion ( Lithium - Ion ) are the newest type available and much better, compact, and expensive than the other two types. Memory is not a problem, and manufacturers claim up to 1,200 charging cycles before replacement.
Charging Time

Is another important consideration when considering cordless power tool batteries. Many older batteries need charging after only an hour or less of work and require six hours of charging time. If you have a lot of work to perform can you afford to wait for your batteries to recharge? There are Lithium - Ion batteries available that only require 15 minutes to recharge.

Stability and Maintenance

With the high cost of replacement batteries for cordless tools it pays to follow manufacturers recommendations for the care and maintenance of these tools. Cordless power tool batteries are just like any other piece of equipment and have an expected service life. When they become worn out and need replacing it is sometimes more economical to replace the entire tool kit. The cost of two replacement batteries is often times more than a new cordless tool with charger and two batteries.


Cordless Power Tools - Batteries Are the Key

Saved Welch Allyn Diagnostic Sets

Monday, 24 October 2011

Lithium Ion Batteries - What You Need to Know About Li-Ion Technology

!: Lithium Ion Batteries - What You Need to Know About Li-Ion Technology

Lithium Ion (Li-Ion) battery technology is one of the fastest growing trends in the tool community, and certainly for good reason. Lithium Ion batteries have the best energy to weight ratio, meaning they pack the most power with the smallest amount of bulk. They also experience no memory effect or, lazy battery effect. This occurs when a battery can no longer accept a maximum charge for having been repeatedly recharged without being fully used (a common symptom of Nickel Cadmium (NiCad) batteries). Li-Ion batteries, conversely, have absolutely no memory and can continually accept a maximum charge. Additionally, Lithium Ion batteries have a very slow rate of charge loss while the battery is disengaged.

What is the difference between Lithium Batteries and Lithium Ion Batteries?

The difference is in the chemistry; a Lithium battery is a disposable power source composed of lithium metal compounds - the key word, here, being disposable; Lithium batteries can not be recharged. Lithium Ion batteries, on the other hand, are intercalated, meaning the lithium ion inside the battery moves between two internal electrodes. This movement, or reversibility of the lithium ion accounts for the battery's rechargeability.

What are the benefits of Lithium Ion Technology?

-- Lithium Ion batteries hold a lot of power and are surprisingly light-weight, especially with consideration to other rechargeable batteries.
-- Li-Ion batteries combine single cell technology with a greater energy reservoir than Nickel Metal Hydride and Nickel Cadmium batteries. They store more power for their size than both NiCad and NiMH.
-- Li-Ion batteries hold their charge for significantly longer than other comparable batteries, and provide steady power until that charge is completely gone. Other batteries gradually and consistently loose power as you work. Li-Ion batteries stay strong until the last push.

Are there disadvantages to using Lithium Ion Batteries?

The disadvantages with using Li-Ion battery technology are generally few and far between, and technological advancements are making them even less so. Manufacturers have recently improved the Lithium Ion recipe to reveal a more reliable battery. Still, every giant has its weaknesses:

-- Li-Ion batteries are sensitive to intense hot and cold temperatures. In extreme temperature conditions, the battery will degrade more quickly.
-- Li-Ion batteries degrade regardless frequency of use.
-- The Li-Ion battery's built-in computer chip tells the battery to refuse a charge once the batteries power falls below a certain point. If this occurs, the battery is beyond repair.

Although these defects are more applicable to the older Lithium Ion batteries, the possibility of seeing these problems is still worth noting. Fortunately, these said defects are fairly rare, and easily avoided.

-- Store Li-Ion batteries (and other batteries as well) in a cool, dry place.
-- Use your Li-Ion batteries often.
-- Be certain Li-Ion batteries have a full charge before storing them, and pull them out every so often to use and recharge. Watch the batteries power level to be sure it doesn't fall below the charge limit.

General Li-Ion Battery Tips:

-- On occasion Lithium Ion batteries require more than one charge (sometimes 2 to even 10) to accept a full charge. The first time you charge your battery, leave it to charge over night. This ensures you'll have maximum power for your first use.
-- To maintain proper balance in your battery, leave it charge over night about once per week for the life of the battery.
-- When buying a new Lithium Ion battery, make certain you are buying a fresh one. There's a chance a battery has been degrading on the shelfs of manufacturer's and distributor's so be certain you are buying a new one. Most manufacturers provide a date code on the battery or packaging. Check dates before you purchase, and be confident you are getting a fresh, high-performance battery.


Lithium Ion Batteries - What You Need to Know About Li-Ion Technology

Hint Pruning Pole Saws


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