Rechargable Appliances


A correspondent writes:
A lot of new cordless appliances use
rechargable lithium ion batteries.
Are they any good?

Most people are familiar with the process of recharging laptop computers, cellphones or iPods. Now there are many more rechargable appliances.

There may be power limitations. Here is an example. When installing ceramic floor tiles, common for bathrooms and laundry rooms, it is recommended that you screw (as well as cement) panels of Hardiebacker board onto the plywood sub-floor, and then cement the tiles to the Hardiebacker board. I found that the Makita 12-volt cordless drill does not have enough power to make a screw go through the Hardiebacker board. I ended up using a conventional (120 volts AC) electric drill for that task. However, the rechargable 12 volt drill is powerful enough to drill through any wooden board, or to drive a screw through it.

Another example is EGO Power+ (pronounced like "power plus") leaf blower, which uses a 56 volt rechargable battery. The ad on TV says that it blows air at a rate "up to 530 cubic feet per second", and it "runs up to two hours on a single charge". I find that these two "up to" descriptions are reciprocally related. When switched to the lowest power setting, which doesn't blow the leaves vigorously enough for my satisfaction, it runs for about two hours on a charge. If you turn the power all the way up, as I routinely do, I find that it blows air as efficiently as the best gasoline-powered leaf blowers -- but then the battery is dead in about twenty minutes. It takes about an hour to recharge.

The need to recharge imposes a couple limitations on the leaf blower. First, use of this appliance is appropriate to maintain your own yard, but it cannot be recommended for contractors going out on professional jobs. Secondly, if you wait until November and remove the entire season's leaves at once, you will be interrupted by several recharging sessions of about an hour in duration. I like to start in September and remove a few leaves each week, so recharging doesn't cause interruptions.

My favorite item is the Ryobi 40-volt rechargable chainsaw with a 14-inch bar. After thirty years of experience, I still cannot get the hang of starting a gasoline chainsaw. After pulling the rope about a hundred times to get the engine started, I'm too tired out to do any work with it. Therefore I heat my home with firewood that I have cut to length using an electric chainsaw. However, with an electric chainsaw, the extension cord is always in a knot, and every work session begins with untangling the extension cord. The rechargable chainsaw is an alternative. The power lasts about 45 minutes, and then the battery must be recharged, and that is assuming that you are pausing half the time. The recharging cycle is about 45 minutes. As an optimal solution, I use an electric chainsaw to spend an afternoon cutting firewood close to the house, and I use the rechargable chainsaw to run around the property cutting long branches into shorter lengths that are lightweight enough for me to carry back to the house.

Recharging the battery of the Ryobi cordless chainsaw is a bit tricky. If the yellow light comes on, it is not charging. You have to remove the battery from the charger and put it back on. Then the red light indicates that it is charging. My understanding is that this instability is common for many lithium ion batteries. The occasional need to lift the battery off the charger, and putting back on, is a minor inconvenience. (I have not found this recharging instability at all with the EGO leaf blower. The recharging cycle works the first time, every time.)

My wife uses a Shark brand rechargable vacuum cleaner, as her only vacuum in the house. I have not tried it myself, but she likes it. It is lightweight. It easily comes apart to pour out the dust, and to rinse the filters under the faucet. It uses a rechargable 25.2 volt lithium ion battery.

A final comment about flashlight batteries. I was dissatisfied the use of with rechargable D cells in a flashlight. The light is too dim. I'm not sure of the reason, but this may because some DC voltage sources put out the nominal voltage if the current drain is low, but when the current is increased the voltage drops below nominal. Therefore, I use regular throw-away batteries in my flashlights. However, I am happy with the use of rechargable AA and AAA batteries in the remote control units for the TV, etc. I also have an inexpensive Dorcy brand camping lantern which takes four AA batteries. I use rechargable batteries in that, and they work fine.

Mike Lepore for