Dewalt replacement batteries are less expensive than the genuine one. That is why more consumers are looking for them. They look very similar in dimension and will fit any Dewalt cordless drill intended for it. They also operate and function just like the original battery but considerably less expensive due to the fact that you are not paying for the product name anymore. It is more like a common battery which has all the basic features and specifications, and the less significant features are removed to save manufacturing costs.
There are also some disadvantages in buying generic cordless drill batteries. Sometimes some companies who want to take full advantage of their earnings use a very cheap body material. So instead of employing a strong material for the plastic casing and locking mechanism they use a softer or brittle one. Using these kinds of batteries in a rough conditions will make them crack easily, making it ineffective in a couple of days. It is also very hazardous once the battery cell inside it is exposed.
If you don’t have the time to actually go out and buy it to the hardware shop, you can order it through online stores like Amazon and eBay. Try to read some feedback and recommendations by individuals who actually purchased and used them. If you are not sure about the product, it is better to get a genuine Black and Decker 18V battery just to make certain and to prevent the hassle of returning it.