KUFUNG Trickle Charger for 12 Volt Batteries, 12V 5A Smart Automatic Battery Charger, Deep Cycle Battery Maintainer for Car, Boat, Automotive, Marine, Motorcycle, Trolling Motor (XL: 5A)

***EDIT*** IT ALREADY STOPPED WORKING LESS THAN 3 MONTHS LATER.****My car had been dead for a week or so. The car has a drain when I'm not driving it and it killed the battery. I couldnt find specifically if this would work on a fully dead battery or not but risked it since it was cheap. Plugged it in, first it said the battery was 75% charged, then switched to 25% then 0% then 50%. THEN it went down to zero and appeared to actually be charging. I think it just takes an hour or so to either repair a super dead battery or acclimate to the battery. Not sure. Anyway once it finally finished and said 100% charged (took about a day), I put the battery back in the car and it started right up. It was so dead before that the lights didnt turn on inside the car and I couldnt even turn the key because the ignition is electronic. So it was VERY dead. The charger worked perfect and charged it right up! Just make sure you have a full day to dedicate to waiting.

We moved from GA to PA during the snow time so the bike stayed in the garage. Finally got a warm day to take a ride and it wouldn' crank but battery wasn't completely dead, cause lights would come on. Ordered this little bad boy and it charged her up. Very easy to use with no issues.

It charges batteries quickly. LED Indicators seem to work as they should (25/50/75/100%). If a charger is all you need, and you remove it when it shows a full charge, I have no hesitation recommending this item.My concerns:1. Listed as 'Perfect for long-term battery storage' I measured its float voltage at 14.55v. (Not 13.5v - 13.8v which is more normal). The device uses 'constant pulse current to maintain charge', rather than constant voltage. I'm unfamiliar with this.2. Listed as having 'short circuit/OVP/OCP/Overload/reversed-Polarity' protection, but it kept charging (what turned out to be a bad battery) to the point where you could cook eggs on it.Not sure I'd trust it to 'maintain' unless you have an excellent fire suppression system installed where you will be using it.

A dead battery shows 100% with all leds on. Did not charge the battery at all after 2x times of use. It is out of return window. I guess I will have to throw it away. Waste of money.

This unit has the power to quick charge and properly maintain charge on many types of batteries. I'm using it to keep my 2 RV batteries and the jet ski charged. I had to quick charge the jet ski battery and it was lightning fast! Buying another one!

Using this item to trickle charge my RV battery over the winter. So far, it is performing well. After first connecting the battery, there was a period of charging to 100%, now it is just "floating".My only complaint is the web-site to register the device is/was not working.

This product must come from China. The instructions are lousy. I had to look up a video on YouTube to see how to use it and I still have questions about how I can tell the difference between fully charged and not working.

Works well, gets a little warm but not enough to be concerning. Have already used it a handful of times and it did what it was supposed to. The battery gauge was helpful.