I have the Skil 2887 18v cordless drill that uses these batteries. The drill is fine. (It's only 3/8", but it gets the job done most of the time.) If I knew then what I know now after having owned this drill for going on 3 years, I would have spent the [...] on a different drill that used lithium batteries. More on that later.
First off, if you buy the Skil 2887 drill for around [...], you get 2 of these [...] batteries. So, essentially you get a free drill and battery charger, which makes paying [...] for one of these batteries a bad idea. I say, take that [...] and put it away. Then next month, buy a completely new drill that uses better batteries like one of those lithium drivers that run around [...]. The batteries will serve you much better.
So, why does this battery suck so bad? For one, they're Nickel Cadmium, which is an older, cheaper battery technology that has memory issues. Basically if you don't completely discharge the battery every time, you will shorten the life of the battery fairly quickly. Also, if you leave it on the charger for extended periods of time, you'll find that it won't be able to hold a charge when you want to use it. They also have poor shelf life -- meaning they don't hold a charge for very long once they've been charged. These batteries in particular have terrible shelf life. If you charge it fully and use it, you'll get an hour or 3 of continuous use. But if you leave the battery sitting there for a day, it'll be dead when you go to use it. And it takes something around 3-6 hours to charge.
With my 3 year old skil drill, I have 2 of these batteries. One of them doesn't hold a charge at all so I'm forced to leave the other on the charger so that it's ready when I need it. That battery is on it's way out too. I absolutely refuse to buy a new battery because it's such a bad value. I'm saving up for a high torque lithium driver.
On top of being an under-performing battery, the clip these batteries use to lock into the drill is such a bad design. It uses a single release switch to unclip 2 locks. This is not only awkward to use, but it loosens over time and the single switch becomes inadequate for moving the 2 locks. It binds inside the battery shell. Essentially it becomes a wrestling match to get the battery loose from the drill. I notice that the new Skil 18v drills use 2 buttons like most other drill manufacturers. So it looks like skil addressed that issue with their new batteries, but if you own an older drill, you're SOL.
The charger that Skil provides for these batteries is a generic piece of junk charger. There is very little logic for preserving battery life. You can't "refresh" the battery. It's just a straight up charger, which is to be expected. If they gave you a good charger, you wouldn't have to spend $45 on a new battery every year. As many people are aware, inferior products and designed obsolescence seem to be part of the business plan of many consumer product manufacturers these days. That seems to be the case with these batteries.
So why lithum then? Well despite being a more expensive (and more prone to explosion) technology, lithium batteries have excellent shelf life. They have excellent energy density and they can handle quite a bit of charging cycles. The only drawback with lithium is that they don't like to be discharged fully or charged fully. 20-80% is their sweet spot. So if you have a charger that understands that, you'll get a nice long life out of lithium batteries. But the main feature to me is the long shelf life. I want to be able to leave my drill sitting there for a while and when I need it, I want it to be ready to go. I'm not a contractor for a living, so I don't use my drill every day, which makes leaving the batteries on the charger a bad idea. Lithium batteries are the way to go. Their high energy density makes them lighter and smaller, and their long shelf life helps them out perform larger, higher voltage batteries.
So, stay away from this battery. Buy a new tool if you have one that uses this battery.