NOCOGENIUS10: 10A 6V/12V Smart Battery Charger – Automatic Maintainer, Trickle Charger & Desulfator with Overcharge Protection & Temperature Compensation – For Lead-Acid & Lithium Batteries

Very nice, compact charger to restore or recharge an automotive size battery. I came back from a trip to find my car completely dead and all I had was an old 1.5A charger. I heard good things about this Genius charger and ordered. I charged my battery up for the most part of a day and it worked great! The clips are of excellent quality and can be disconnected for alternative components like a ferrule-based setup. The Charger is also small - it's perhaps 4X the size of a modern cell phone in terms of thickness and maybe 1/4 again as long. There are 4 lights indicating a charge level - the level it's working on "pulses" slowly until it's done and then it's solid and the next level pulses. Easy to understand.Great charger with quality components - definitely recommended!

I have a very old truck. I hardly ever drive it and it has an alarm (which I really should just disconnect!). Long story short-- this truck drains and destroys batteries. I'm not sure if it is ONLY the alarm, or if there is a short or drain somewhere else. The point is, I came out to a dead battery AGAIN! For some reason, I thought re-conditioning old car batteries was a scam, but I figured, if it doesn't do what it claims (recharge and re-condition a car battery) then I'd just return it. The price was less than a new battery!After reading the very simple instructions, I plugged it in and charged the battery. So far so good. Next, per the manual, I ran the re-conditioning cycle. I was still skeptical, but I hooked the battery back up and (after the alarm jump-scared the wits out of me), started it up. It was perfect. I tried again-- perfect. The battery performed as if it was new again. And it stayed in great shape until I neglected the battery to death again a couple months later.Now bear in mind, this battery wasn't terribly old (maybe 2 years?) so I can't speak to VERY old batteries. But I have now resurrected the same battery (Just a basic AAA replacement battery) from completely dead to working like new at least 5 times. I didn't know that was possible. I'm a jackass for continuing to neglect the battery and letting it drain out, but this product resets it back to perfect every time. I'm writing this review after almost 9 months of use. This should be in everyone's garage.

EDIT 2/26/24: I am now the blocks "AAA". Been helping people start their cars when jump starts with cables have not worked. Definitely handy to get other people out of an otherwise expensive pinch.I have a car battery that I purchased around 2016 (date of review 1/3/24). The car itself does not get driven much, at most 2-3 times a week no longer than 15 minutes one way.Throughout the years I've drained it by leaving the car lights on. Its always required a jump start after that to get going again. Recently I've been an idiot and been leaving my lights on more frequently. Eventually it required me to jump start everytime I wanted to turn on the car. It was becoming a hassle and I was about to call it quits and purchase a new battery until I came across Project Farm's review on battery chargers. This was at the top of the list so I figured to give it a shot.I was not disappointed! I charged it for 4 days straight, put it in my car, and it started right up. Not surprised considering it was just charged but the real test laid ahead. I was going to be out of town for two weeks and leave the car sitting. I came back two weeks later and the car started up, no hesitation whatsoever, as if it was a different battery!The NOCO Genius 10 saved me about $150-200 at least in a brand new battery. On top of that, I can now use it for other batteries in the event of any similar issues. The instructions on the other hand are a bit confusing and had to rely on YouTube comments to piece it together.For those who are confused at what to do, I did not do a 12V repair (function which this unit has) as it requires the battery to be completely charged first. All I did was charge it straight for 4 days uninterrupted.When first put on battery to the charger it will be in standby mode. You push (or hold depending on what you need) the MODE button to select your desired option. I was charging a lead acid battery so I selected 12V. The meter at the top slowly advanceD from each of the four bars until the final bar was pulsing green which indicates its charging to full (over 80% I believe). The green charging light continued to slowly pulse even on the 4th day but I took a gamble and disconnected it from the battery. For the battery to be 100% charged, the green light should stay solid. That means my battery worked 2 weeks later after sitting and it wasn't even at 100%.The unit can also force a charge on batteries that are extremely under voltage. Thats a separate setting that I haven't had to use yet. It can also charge AGM and Lithium but I believe the 12V repair function is only for lead acid.Unfortunately I had to go through 3 separate orders because the first two were from Amazon Warehouse and I encountered issues with both, consecutively. I ended up getting frustrated and just purchased a brand new charger.Pros:Solid build qualityExcellent cable connections with weather coversCompatible with a wide variety of batteriesRepair and Force charge batteriesCons:Poor instructionsCharge is slow BUT I think thats how these chargers workTL;DRTry this first before rushing to get a new battery it is a good investment that can save you a lot of money