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

Reliable, easy to use, durable

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.

way better and cheaper than what you find in most autoparts stores

I've been using the BLACK+DECKER BM3B Fully Automatic Battery Charger/Maintainer for a while now, and I own more than one — which should tell you how much I trust it. It does exactly what it's supposed to: keeps my 6V and 12V batteries charged and maintained without any fuss. The automatic switching between charging and maintaining modes is a great feature, and the included cable clamps and O-ring terminals make it versatile for different setups. One thing to note: while it's generally durable, rain can affect its performance temporarily. If it gets wet, it might stop working until it dries out. That said, once it's dry, it picks up right where it left off without any lasting issues. I just make sure to keep it sheltered when possible. Overall, it's a solid product that does its job well - just be mindful of the weather if you're using it outdoors.

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.

Does as it should.

I've used various brands of battery maintainers over the years including ones from Porsche, Black & Decker, Harbor Freight, etc. While I'm not an electronics expert, I do know how to properly use them. I purchased this model from Amazon after using a different model B&D maintainer with good luck for over a decade. This one was to replace a $6 Harbor Freight model that failed after the cord became frayed. It arrived quickly (thanks Prime) and I hooked it up the next day. Or at least tried to. Using the alligator clips I noticed the red LED came one (indicating the polarity was reversed or some other charging problem). Now, I've hooked these up 100's of times, but I double-checked anyhow, but it was hooked up correctly. I thought maybe it was the clips themselves, so I installed the wire extensions directly to the battery but had the exact same result. Lastly, I tried the included accessories adapter (cigarette lighter adapter) which is IMPOSSIBLE to hook up backwards, but same thing - red warning LED. For giggles, I purposely hooked it up one last time with the alligator clips installed backwards, thinking maybe this unit's internal wiring was backwards also - but nope, same issue. I then emailed the listed manufacturer (Baccus Global) to inquire whether or not the red LED was supposed to be on all the time on a fully charged battery as the manual doesn't address this issue at all. I went into detail the steps I had taken (as I recounted above) and the various methods of installation I had already tried. It took them THREE days to respond to the email, even though their manual clearly advertises 24 hour service via the website. And then, it was obvious they hadn't even bothered to fully read/understand my email as I simply got a canned reply saying "not to use other maintainer cords" (which I never did, nor said I did) and that the red LED indicates reverse polarity (duh) and that if I had any other questions to let them know. Needless to say, back to Amazon it went and writing this review as I pick out a different (non-B&D) model. If I could give less than one star to Baccus Global, I would.

Item is a very good buy. Works great.

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.

So far so good. I received this in very short order and as expected, it is a Black and Decker quality product. I have hooked it up to my 1984 Corvette for it's winter hibernation and it appears to have done an excellent job charging then maintaining the battery. I will post an update on this product after it has been operational for a month or so and again in the Spring of 2018. I have used products similar to this in the past and have always been happy with them, I am sure this product will carry on the tradition. Update: This product worked great for me, left it plugged in all winter and just fired up my car this afternoon without any problems. It let me know when there was a problem with a little red light, that happened a couple times when the clips on the battery were bumped. Another great product by Black & Decker!!!

Excelente produto