Buying a 20V Black and Decker battery might seem straightforward, but small mistakes can cost you money and performance. One common error is purchasing a battery that isn't officially compatible with your tool model. While cheaper, some off-brand options don't deliver the same power output or safety features. Another mistake is ignoring amp-hour (Ah) ratings—higher Ah means longer run time, which can make a big difference for heavy-duty tasks. Many buyers also forget to check warranty coverage, leaving them unprotected if the battery fails early. Choosing the wrong charger or using an old, worn-out one can shorten the battery's life. Some users buy the cheapest option, only to replace it sooner due to poor quality. Others overlook the benefits of having a spare for uninterrupted work. Always verify authenticity, specs, and reviews before purchasing. A smart choice today ensures your 20V Black+Decker battery performs reliably for years.