BLACK+DECKER BM3B Fully Automatic 6V/12V Battery Charger/Maintainer with Cable Clamps and O-Ring Terminals, Multi, 1.5 Amp

Somehow the world has made me come back to this product page a little over 8 years later and I figured I would write a quick review. TL;DR - Charger works well and has given me zero issues. Pros: The cord is plenty long for my garage outlet so I don't even need an extension cord when plugging in my "race car" as my kids call it. I only get to drive it once every few weeks so I throw this charger on there just to not worry about the battery possibly going dead. The power inverter is in the middle and can be mounted so you could possibly run power from an outlet, mount it on the wall or a workbench, and then have a good amount of cable to plug in a battery, depending on your application. It includes several ways to connect to the battery terminals. I just use the clamps and I have not had any issues. They are pretty sturdy and should hold up to normal use without issues. The unit has an easy to understand switch and lights for status. Switch to convert it from 6V to 12V, depending on what you are charging. The status light has simple icons that give a good indication of what the charger is doing. Cons: Not an issue for me but something you should be aware of with this (and likely most chargers of this type in this price range) charger is that it's not going to be super fast at charging a battery that is very low. Most of the time, that's not a big deal as its intended to maintain a battery that is sitting for long periods of time. Just don't assume you can plug this into a dead battery and come back an hour later and have it ready to go. Depending on how empty the battery is and how much power is needed to turn whatever you are powering over, it will likely take longer than that. Overall, well worth the 20 something bucks I spent on it. Not something I can always say with stuff from Amazon these days.

I plan on using this on a vehicle to maintain the battery when I will be away for weeks or longer. This B&D labelled unit specifies it switches to float mode when battery if fully charged. Also it is rated 1.5 amp, so I feel it will not damage my battery. I have not use it yet, but volt meter showed it was charging at 15 DCV, the correct lights on the unit were light, so I am confident it will keep my battery topped off when I am not using the vehicle. Compact size with nice long cords. *Note the unit does not come in a Black and Decker printed box, but a plain brown box that looks like it was made for the unit. Also the first unit I received was missing the alligator connector, and Amazon took the return and shipped my reorder immediately. Easy to use, and a good value.

I finally charged the dead and drained battery of my car. It doesn’t charge the dead battery initially, and I read the instructions that it requires a minimum of 2 volts to charge it. So I thought I was out of luck because the battery was completely drained to jump start it. I left my car in storage and hadn’t run it for a while and the battery slowly drained completely. Out of desperation, and after reading the instructions for awhile, then I realized that because it has a polarity sensor to detect the correct positive vs negative poles, so I figured that the minimum of 2 volts in the battery is designed for the polarity sensor to charge it with the polarity in order to prevent shorting the battery if it charges with the opposite polarity at the dead state without any minimum voltage to ensure it’s the correct polarity. So then I decided to trick the charger to start charging the dead battery by giving the dead battery some minimum voltage by connecting the jumper cable to another car’s functioning battery, but not attempt to jump start it yet (because the other car’s battery doesn’t have enough amperage to jump start the completely drained battery). So after I connected the jumper cable to the dead battery to another car’s good battery with the correct polarity first. Then I connect the charger cable to the dead battery. Now the charger detected the minimum 2 volts (borrowed from the other good battery) with the correct polarity, and now the green LED light starts blinking. So it’s a good sign that the charger is beginning the charging process. Then I disconnect the jumper cable and let the charger continue charging without the jumper cable connected. So that did the trick to start charging a completely drained/dead battery by borrowing the minimum 2 volts from the other battery to trick and override the polarity sensor to turn on charging the drained battery from the dead state. It finally fully charged my dead battery after it trickle charged for about 24 hrs because it’s only charging at the rate 1 amp so I expect it to take that long to fully charge a dead battery. After that I can start my car on it’s own and it works fine after that. Now I keep the car battery continues to charge by the charger as maintenance rather than letting the battery to drain dead before charging it for a car that has not run for awhile. And I need the run the car once in a while to circulate the fluid and engine rather than letting it sit there for a month. So the charger can charge a dead battery if you know how to trick it to make it work.

Had bad experienced with NOCO always stuck on Standby, try out B&D and received 2 dead ones when plugged in power, no LED lit. Returned to Amazon, got 2 new ones. Let see how their quality control this time. Update: Got 2 new ones works fine, somewhat my fault and somewhat B&D poor design. LED will not turn on UNLESS battery cable is connected to car battery then connect to charger with power AC plugged in wall socket to complete the loop. If only AC power plugged into wall socket, LED is OFF which is poor design that made me think device is defective. It should have power/ready LED but this device only have CHARGING (Green) or FAULT (Red) LED. The first 2 charger I returned probably works fine but I'm used to plug in a device in AC wall socket, LED power/standby should turned on first. I got no LED light so thought it malfunction. So before you claim the product is defect due to NO LED LIGHT lit when plugged into wall AC, make sure connect the other end to your battery terminal to make complete loop in order for GREEN LED to flash (charging.) This is not a good friendly design but it works and fairly priced.

I find this battery charger to be simple to use and accurate while charging. I use this charger to recharge battery on a propane electric generator and a backup power supply battery with power inverter for 12 vdc to 120 vac for garage door on grid power failures.

The recent purchase was a second unit having had many years of solid experiences with the first. It is ideal for longer periods of vehicle storage. It’s easy to use and priced right.

This was the best charger that I had, regarding maybe 6 or 8 different brands. Like most other chargers for sale in CA, it now charges the battery up to 12.8 volts or so, and stops charging. Your vehicle, and most GOOD chargers, charge to about 4.7 volts. A good charger then tapers off to a, "float" charge of at least 13.15 volts. This charger will only charge for a matter of minutes, then pretends that the battery is fully charged. Even if your vehicle has sat parked for a few days. My old review is below. I have many 1 to 10 amp chargers. None of them charge at more than 2.6 amps, as I never let the vehicles sit for more than a few days, without a charge. They ALL float at MUCH higher voltage. Even after 2 days charging, any car battery that I charge, drops to 13.15 volts, in about one minute. So I see no reason at all, for a battery charger to float a car battery, at 13.78 to 14.5 volts. Especially if the charger will be left on overnight, or for a few days, or longer. This is the ONLY charger that I have bought, in years, that has sufficient length in the AC cord. The 12 volt cords are also plenty long. Charging power is plenty, unless U need a dead battery to function, in a short period of time. UPDATE I just read some horrible reviews for this item. We have an Electrical Engineer in our family. He suggested this charger. I check my batteries often. When this unit is, "floating", day after day(well after battery is charged), it is always about 13.2 volts. (in hot weather it may be a bit higher) I have 3 vehicles with 2 huge batteries each. With THIS charger, I replace batteries less often.

I've been using this thing to keep my generator battery charged up and ready to go for over a year now and it's still going and working perfectly.

Good product

i used it for straight 4 months, than it broke cuz its 110v and we have only 220v here in Saudi.. but it stood this time! i believe if it was 220v compliant i wouldn’t need ever to change it

How good are they, send a product to Australia with a US power plug on the product. How am meant to use the product? Very disappointed with the distributor.

I purchased this to trickle charge my dead lawnmower battery and man did it work. The battery was juiced up enough in a few minutes to power my solar charge controller. After that it was smooth sailing. My next project will be in the spring with my functional lawn mower battery. The biggest thing though is all of the connectors. I usually use a combination of tin foil, old coffee cups and air matresses to make the connections between my circuits. With this unit you pretty much get everything you need in terms of battery clips, o rings and a cigarette lighter attachment that I am still trying to figure out. (Charge the battery via lighter? hmmm) All in all for this price i should have bought 2 so I could have a second set of cables. The only negative i can come up with was that it does make this eerie whining noise, (Similar to a model train grinding its wheels on the track while in a sumberged tunnel but louder). I kicked it and the noise went away but still recommend not keeping it under your bed when it is charging.

Excelente produto