BLACK+DECKER BM3B Fully Automatic 6V/12V Battery Charger/Maintainer Review [2023]

July 23, 2023
7.4Expert Score
BLACK+DECKER BM3B Fully Automatic 6V/12V Battery Charger

The BM3B fully automatic car battery charger is an incredibly useful little device. It’s small, lightweight and uncomplicated. However, don’t be fooled by its apparent simplicity. The BM3B is still a smart charger that can automatically detect the level of charge in a battery and switch between charge mode and float or maintenance mode as needed – all without you having to do anything except connect it up and select your battery voltage.

  • The unit is lightweight and compact.
  • It works on both 6V and 12V WET, GEL and AGM batteries.
  • The BM3B is fully automatic with a charge and a maintenance mode.
  • You get two ways to connect the BM3B – clamps and ring connectors.
  • The casing is durable and has a built-in mounting bracket to keep it out the way.
  • The unit comes with a limited one-year manufacturer warranty.
  • The charger only goes up to 1.5 amps, meaning it won’t charge a battery quickly.
  • The unit is not waterproof.
  • The BM3B was not designed for use outdoors.

When it comes to power tools and home improvement products, Black and Decker is an international name that has a reputation for providing the best. The company has been around for over 100 years, opening their doors in 1910, and has been providing both professionals and DIYers with the tools they need to get the job done. These manufacturers have also stayed ahead of the curve as technology changed over the years and they have created some truly innovative products.

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Overview and Features of the BM3B Car Battery Maintainer Black and Decker

The BM3B is a fully automatic car battery charger and maintainer that does just what the label says. In terms of power, it goes up to 1.5 amps, which means it won’t charge a battery particularly fast. However, it will monitor the level of charge on the battery and switch itself over to maintenance or float mode once the battery is fully charged. The unit is incredibly safe to use and is designed to be left attached to vehicle batteries for long periods of time.

This device might not be particularly powerful, but it does work hard and keep on working hard as long as you need it to. The small size and low weight (only 1.3 pounds) make it easy to keep out of the way. The casing also has a built-in mounting bracket, so you can hang the unit on the wall next to where your vehicle is kept. This is incredibly convenient for a speciality vehicle that you don’t use all the time but want to make sure that it’s ready to drive whenever you want to go – and this is exactly what the BM3B is made for.

You can use the BM3B on a wide range of vehicle batteries, from small motorbikes and lawn mowers all the way through to RVs and boats that use deep cycle batteries. It has the option to switch between charging 6V and 12V batteries, and will work on GEL, WET and AGM batteries. The unit also comes with both ring connectors and clamps for connecting it to the battery in need of charging, plus it has reverse polarity protection and won’t start charging until you rectify the connections. A warning light will come up on the unit’s display to alert you to the problem.

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Conclusion and Rating for the BM3B Black & Decker Charger

Zena Product Rating: (4/5)

The BM3B Black and Decker car battery charger is a handy little unit that is sleek and small, making it easy to store and to keep out of the way even when in use. It might not be very powerful, but it will do the job of maintaining just about any 6V or 12V battery in a vehicle that isn’t used very often.

This device is not the right choice for someone who wants all the extras, or wants a device that will do more than just charge and maintain. For example, if you need to jumpstart a vehicle or want to do checks on the health of a battery, you will need another device to perform those functions.

If you are looking for a Black & Decker charger with a couple more features, we suggest reading our review on the BC6BDW.

Where this Black & Decker charger comes into its own is in situations where a vehicle is left in storage for long periods of time. It’s an ideal choice for boats or recreational vehicles that are only used when you’re on holiday or in a particular season of the year. You can hook up the BM3B and leave it to do its magic on the battery while the vehicle sits in a garage or storage unit, waiting for you to come and play.

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James Olive