NOCOGENIUS1: 1A 6V/12V Smart Battery Charger – Automatic Maintainer, Trickle Charger & Desulfator with Overcharge Protection & Temperature Compensation – For Lead-Acid & Lithium Batteries

There is a reason the NOCO GENIUS smart car battery charger is so popular. It works well, it is very simple to operate and solves the major headache for car owners who must leave their vehicle unattended for weeks or months at a time.It used to be when you turned off your vehicle and removed the key, all power was off and there was no drain on the battery. Not anymore, there are all kinds of things that always stay on now. If you have a newer vehicle, you know what I am talking about. I went away for just a couple weeks and when I returned my car would barely start. I didn't think too much of it but when I went away on a 6 week trip this past summer, I came home to a super dead battery in a 3-year-old car with 20K on it. Nothing worked, no lights, no locks, no trunk, nothing… I even had a very difficult time getting into the electronically assisted doors. Now to be honest, after a couple weeks away, my car sent me an email saying it was shutting down systems to save the battery. When I returned, I measured the battery voltage, and it said 3 volts, it was so dead. I put a charger on it overnight and the next day it was only 6 volts, and it still would not turn over. I was able to get it started with one of those new micro jump start devices that I remembered I had (amazing little devices) and I took it to the Lincoln dealer and they replaced the battery under warranty but said anytime I go away for longer than a week to put a trickle charge on it or remove one of the battery posts to prevent the battery from completely discharging but they really didn't like that idea and preferred the trickle charge because a bunch of electronic settings will need to be reset once you hook it back up. Moreover, I am seeing the latest luxury vehicles now are coming with two batteries, one just as a starting battery and a separate "house" battery to run all the electronic stuff that is running in the background. That is the way yachts do it. All these car apps that talk to the car via satellite, the various alarm, safety and convenience stuff will kill your battery if you don't regularly use your vehicle, it is that simple.While this can charge your battery from a very low state, keep in mind it will take a very long time, it really is designed only to “maintain” your battery, and does not do an efficient job charging it from a dead state. Batteries require a charging “profile” depending on the type of battery, most have an initial heavy duty “bulk charge” phase followed by a “float charge” or a maintenance level. This charger only addresses the maintenance charger of about 1 amp or so.So, what you want is a SMART trickle charger that is smart enough to know the battery type you have AND smart enough to know when to stop and start charging at a very low amperage just enough to keep your specific battery type at its optimum charge level for the longest lifespan. The NOCO GENIUS does just that. What I like about it the most is that it is super simple, so simple my wife can do it without freaking out about doing harm to anything. The other thing I like about this is the cost. It is very reasonable and on sale it is a screaming buy. Everyone needs this IMO. Get it and it will save you way more $ than it costs, as well as a massive headache when you come home from a vacation to a dead vehicle that will not budge, and you must arrange to have it serviced in your garage!Positives:• Effective trickle charger• Simpe to connect and operate• Will not do harm to your battery (or cause a fire) from overcharging• Safe for long periods of unattended operation• Reasonable costNegatives:• Not the best charger for charging batteries from a very low state• Will not “jump start” your vehicleI think you will like this useful item, and it will provide many years of service for a modest price.5 stars

I have a truck that mostly sits in the garage. Every time I need to back it out of the garage, the battery is dead.I know that just sitting isn't good for batteries, not to mention this battery is several years old.Now keep in mind, this is a large amp battery for a SUV, which was so dead, a turn of the key and I didn't even get lights on the dash. I stuck this little charger on it and it took a day and a half, but it charged completely. Ok, now I'm beginning to get a tad impressed.I have two of those old type chargers, you know the ones that after a while you can hear the acid boiling inside the battery, and the battery is getting really hot... you know the chargers that tell you not to leave it on your battery for any extended period of time as this might (will) damage the battery (possibly even start a fire). Well... no more.I'm a total convert now to using smart chargers, and this one seems especially good. I really hope I don't find some little something that breaks 6 months from now, cause I really like this charger! It seems very well designed and made and most of all, it works great.The only negative I can find, it has a single button to select one of several charging modes, and LED's to indicate which option you have chosen, and those LED's are pretty much self explanatory, as well as an advanced mode where you have to push and hold the single button to enter advanced charging mode. For example, if your battery is so bad, the charger cannot detect there is even a battery hooked up, you can tell it to go ahead and start charging anyway which is a really nice feature. As another reviewer mentioned, when you need to use some of the more advanced functions, if you've lost the booklet, well... good luck. The multi-language booklet briefly explains all of the options, what the LED's mean, and that's pretty much it, verbose it isn't..It comes in a really nice packaging, like you're really getting something ( and you are), the unit itself seems well made and thought out, you would think a bit more of an effort would have been put into the manual.But, perhaps the product speaks for itself... and it does. And, after all most users will hook it up to their 12 volt car/boat/motorcyle battery, plug it in, select the regular 12v battery option, and that's all most will ever need. Once the battery is charged completely, the charger senses that, and switches automatically to just maintaining the battery. If you loose power while charging (or maintaining), this charger just picks up right where it left off, so there is no worries about pushing buttons or selecting modes, it knows what you were doing before, and starts right back up with doing it again.Am I glad I got it: YesWould I buy it again: Yes.