NOCO GENIUS1: 1A 6V/12V Smart Battery Charger – Automatic Maintainer, Trickle Charger & Desulfator with Overcharge Protection & Temperature Compensation – for Lead-Acid & Lithium Batteries

Great little 'trickle' charger, for any vehicles that have to sit around (in storage, etc.), or in challenging weather!! I have one, on my RV, stored in a chilly climate, and it keeps my battery in top condition! Bought another one, to use here at home, with another 'weekend' car, that has some minor issues with a slight battery drain. It is also very very adaptable, because it works with older, and newer battery types, and charges at appropriate intervals in order to not damage those newer type batteries.

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: Yes Would I buy it again: Yes.

Takes a while to fully charge my truck battery, about 3 days!! But it was easy to set up and understand. It's continued to work over the years I've had it and overall it does it's job and really does recharge the battery fully! Very nice little affordable product. Thank you!

I've had products that came with rather poor instructions. This device came with NO INSTRUCTIONS AT ALL! That said, once I found instructions elsewhere, it seems to work well and is reasonably easy to use. My car battery, in the car, went from pulsing red to solid green overnight. Hopefully it will prolong the life of my battery. If not I'll come back with an update.

I will try to be as honest as possible because I depend on other people's reviews and feel I want to help the best I can: Item arrived just as described. This appears to be a well-made and quality item. Every Winter I must totally disconnect my Riding Mower Battery to keep the Engine clock on the mower from wearing it down. In the spring I must hook the battery back up, cross my fingers and hope the battery has enough charge to fire the engine up. I decided enough is enough and invested into this little gizmo. WOW am I impressed. I got the 1 Amp because I do not need it for charging dead batteries but just to maintain the mower battery over the winter time. I also picked this one for the mower because it plugs in directly. I did not wish to have a smaller cord run across my shop floor all winter while I walk on it. SO, I got a 15' extension 12/3 Heavy Duty cord to run to the mower. I plugged this item into the cord and hung it on the back of my Zero Turn mower. Then I ran the battery clips to the battery posts. This way I'm walking on a thick heavy duty extension cord all winter, which will be fine. I can even roll my wheelbarrow on it without incident. My mower had been sitting about one month unused when I decided to purchase this item. Once plugged in, it did everything exactly as expected from me watching You-Tube videos and such. I saw it was charging and left it alone for a few hours. I came back and had a solid Green light on meaning it is now just maintaining. I have checked it daily and it's working great so far. Now I will not need to disconnect my mower battery ever again AND the battery is fully charged when I'm ready to start it up again this spring. I will NOT be using this item during the spring or summer months because I run my mower once or twice per week as a normal. I Recommend. Good Luck.

Okay, I did NOT expect this little thing to work, but it did and might for you IF you have patience. My Grandfather who was MoAT (Mechanic of All Things) owned back in the day what I thought were REAL chargers, they were so big and heavy they had to be put on wheels and rolled around, they had giant switches that'd illuminate and while I'm probably purely imagining this they were plugged into 220-volt outlets. This thing fits in the palm of my hand, just as pictured, smaller than most mobile phones. "Huh," I said, "this should be comical." I hooked it up and, as others have said, figuring this thing out is NOT straight forward, the instruction manual is weak to say the least, the good news is, as I found, there are many intrepid experimenters who, like me, bought it on a whim and did some trial and error which it'd seem 99% of them got the thing to work to their needs, just like me hence, I'm taking the time to write this review. What this lacks in coherent features or instructions it makes up for it in the end by eventually (boy I mean eventually) getting the job done, for that honestly I'm giving it a generous five stars, because it did what I wanted it do against all odds, just like the Phil Collins song. ("Just take a look at my car now, 'cause it's finally starting here.") To get the to point, this took TWO WEEKS to charge a completely dead battery in a completely dead system. If it'll help anyone I own a 2000 Lexus RX300 that is, in fact, drinking age, if I could find a small ute-friendly bar to have a couple with me of which, in terms of trusty old friends, this boring beige over beige has been one of my best now with over 270,000 miles with no reason, per the Lexus dealer, to give up the ghost before 300,000. Toyota quality and then some with only wearables and maintenance needed BTW, the car has only had one issue, eating car batteries every four or so years. Being a cheap bastard and Lexus parts are pricy I've chosen battery over a slightly-off generator which brings us to the recent hullabaloo and the need to be the Noco Genius, though it'd prove not straightforward as I hoped. Hooking up the Noco Genius you get a slowly blinking light, like a heartbeat, that will tell you nothing really. Also there's a force-charge setting where you hold the button (there's only one button on the whole thing, this thing is basic) it supposedly will force a charge into a battery... this doesn't work, at all. After some digging it supposedly only does this if a battery is below some arbitrary limit which, my battery was completely dead, kaput, nada, force charge only made the 6V light go on which, apparently, is what others experienced. Point being, don't hold you breathe. I kept trying to charge the battery but it didn't budge, didn't budge, didn't budge, then I had a thought and said to myself "self, what if I unhook the battery, THEN charge it?" As in, is it because it's also hooked to my car hence current is going other places? Mind you, this thing is only one (1) amp, that's very little, if you're looking for a quick charger or something to charge and jump your car, this ain't it, have you seen the size of this thing? Ha no, no, but it will trickle, very slowly, a charge into your battery... if it's not hooked to the car. Listen, some people this may work when the battery is not hooked up and, in fact, I hooked my battery back up AFTER this thing actually worked and then hooked up the Noco to it and it did, in fact, go from red blinking to green, sooo, yeah, that happened. But I'm burying the lede here: The Noco charger worked for me but ONLY after it was hooked to the battery without being connected to the car. Total time to charge the battery not hooked to the car? About 36 hours. Great? Eh, there's a pandemic, I'm not really going out much so had time on my hands, not to mention my wife's car. In summation, IF you have even a completely dead battery or run down battery and IF you don't have to go anywhere in the next two days and IF you're comfortable unhooking the leads from your car to your battery so that it'll only be charging the battery itself this Noco Genius is, er, uh, genius! It really works! It works and for the cheap cheap cheap money its worth every penny. If this thing cost even 50% more I'd be taking down stars but this thing cost less than a steak dinner (back when I ate steak) so suffice to say it got my battery charged all the way up, hooked up to my car and after the computer was all "what the... ??? Was I in a coma" my car fired right up and ran, I even drove it around a bit. This would be a good thing to own for just-in-case as its just in case money. If you have any situation close to mine, get this trickle charger, if you need the big guns, well, open up your wallet and say ah. Luckily most of us, probably 99% of us, if your battery is run down, this will do the trick. Best of luck!

These NOCO charger/battery maintainers are Great! So good that I bought a second one so I can keep one on tge mower all winter and one on the generator all the time! Small, light weight and easy to use, they are convenient and effective! The cost of 3 of tgem is still less than one battery replacement so get one for each battery that you arent using very often and you will be glad you did when you go to use them and they are healthy and ready to go! The one amp size is good enough for maintaining even large batteries because you arent charging them quickly anyway. If you need to charge quickly then you need to get something else then these will work to maintain the charge! Smart!

I have a 12V AGM battery, three years old, which has taken a lot of abuse from me since I drive only 4 miles to work and take longer trips than that only once every two weeks. Lately, I was staying home because of coronavirus, and I only took my car out about once every three weeks. Needless to say, the battery died and I could not start my car. All lights were dead upon opening the car door. I got the Noco Genius2 to try it out. I was amazed at how small it was. I checked my battery with my voltmeter, and it was 1.9 V. I hooked up the Noco Genius2 and the first LED started blinking, indicating less than 25% charge. I noticed this Noco was rated for 40Ah and my car battery is 80Ah, but I read in the reviews that it should still work, just take longer. Well, I left it on about 20 hours and the first LED never stopped blinking. I checked the battery with my voltmeter, but the voltage was jumping all over the place, so I thought maybe desulfation was taking place. Desulfation can take a long time, so I left it run overnight again and the first LED was still blinking the next day. I unhooked the Noco to take a steady battery voltage reading, and the voltage reading was 0. I was pretty disgusted at this point, thinking either the battery was unrecoverable, the recharger was defective, or maybe I had a load on the battery (like leaving the headlights on, but I knew it wasn't this). I decided to unhook the ground clamp from the battery terminal to try it again. The voltage reading jumped up to 4.2 V with the ground clamp disconnected, so I didn't have to use force mode on the Noco (this is a special mode that forces recharging if the battery voltage is too low). I ran it another 20 hours, and the first LED never stopped blinking, indicating less than a 25% charge. I was ready to give up this point, so I unhooked the Noco and took a battery voltage reading -- lo and behold, it read 12.3 V. Good things were happening, but I didn't understand why the second LED wasn't flashing (indicating between 25% and 50% charge). About 5 hours later, the second LED did flash, then a couple hours after that, the third LED flashed, and then in a couple more hours, the fourth and final green LED started flashing, indicating between a 75% and 100% charge. I left It hooked up over night, but the next day, the green LED didn't stop flashing. I ran it another day, and the next morning, the green LED was still flashing. According to the instruction manual, it turns sold when 100% charged. I disconnected the Noco at that point and took a voltage reading -- it was 13.3 V. Not super fantastic, but above 12.6 V, where I could start the car. While the ground clamp was disconnected from the battery terminal, I took an amp reading and it was drawing only 13 mA, well below the 50 mA that I would start worrying about. I hooked up the ground clamp and was able to start my car, and I think the battery is fine now. I was really impressed at the Noco's ability to revive a battery that apparently was in pretty sorry shape. I think the instruction manual should say to disconnect the battery if the voltage is too low -- it certainly seemed to help in recharging. Also, if you need a faster charge, don't get the Genius2 -- get a Genius5 or a Genius10. In my case, I didn't care if it took two weeks because I wasn't going anywhere. And if you're staying home from coronavirus, drive your car once in a while. Now that I have the Noco, though, I can just leave it hooked up.