BMK 12V 5A Smart Battery Charger Portable Battery Maintainer with Detachable Alligator Rings Clips Fast Charging Trickle Charger for Car Boat Lawn Mower Marine Sealed Lead Acid Battery

If your have variation of voltage from the utility (100-240), this product works as designed. I am a photovoltaic technician and use it to keep battery toped of & if a battery is lying around--it will prevent it from getting sulfated. I reached out to a name brand & I was disappointed that the rep (owner/ceo), didn't even know that his competitors have the voltage variation available like this offers. It prevents it from killing the power supply (charger) if you have constant voltage sages. I waited some time before evaluating it. It charges up to 14.4 vdc (for agm & gel batteries) & back to 13.6 vdc after the battery is charged (floating)--as it should. Have been using it for various weeks consecutively w/o a hickup.Update: I purchased a 2nd unit to maintain my 2nd car's battery & the other unit has been reliable. I recommend this unit. Works as designed, a very good price, I have had the original one connected weeks straight day-after-day. Worthy buy.Update #2: have been using this unit for months straight in a row DURING HEAVY voltage sages & outages AND OVERVOLTAGE situations (scarry situations) and to my surprise--still ticking as expected (better than). I have two other chargers doing maintenance for car batteries and I now have to purchase a replacement units (plural) for that usage. The only reason I don't purchase 1 or 2 more of this unit is because I need a higher capacity. I am going to look into seeing if this manufacturer has a higher capacity... i do like to give credit for a good quality item for a fair price. Good purchase

I really like that it is simple to use.I really like the SAE connection.I really like the quality of the battery clamps.I use this on my motorcycle over the winter, plugged in 24/7 to keep my battery health at 100% (or as close to original as possible)!

I've had this charger just over a year now. In 2020 I stayed home a lot and drove less than 1000 miles for the entire year. My car was frequently parked in the garage for 1 to 4 weeks (or more) at a stretch without being driven. And oftentimes trips were local and quick without enough drive time to recharge the battery. I found that after about 10 days of sitting undriven, parasitic draw would reduce my battery's voltage below 12.6V. The charging and maintaining features of this unit worked really well to keep my battery charged up and reliable. Only once (the first time) was the battery below 12.5V. The BMK charger did what was expected and never got more than barely warm during the 8 or so hours it was charging, then switched to float mode. The battery itself never got warm either. Good job! All the rest of the times I've used it, the battery was between 12.5V-12.6V when I connected the charger. As expected, it took care of charging and went into float mode. BUT 5 times during the year it did something unexpected: it turned off a few hours after doing its typical routine. I have no idea why. The temperature in my SoCal garage was always moderate or cool. When I'd see it off, I'd check AC to the changer (always on) and would completely disconnect the charger from AC and the battery. Checking battery voltage with a VO meter, it was usually between 12.8V-13.1V. After re-connection of the battery to the charger and then charger to AC, it'd still not turn on. So weird. The first time it happened I was sure it had died. But a couple hours later I tried again and found it worked just fine. More weirdness. But in a good way this time. Just recently it turned itself off for the fifth time in the past 13 months. Once again, I tried to reconnect it right away to no avail (which is what I expected). After leaving it disconnected for a couple hours, when reconnected, it worked like it was brand new. It seems to have an occasional, mysterious reliability problem. That's why I'm knocking off one star. Except for that issue, this unit has been a great help keeping my car's battery ready, even when I've not driven the car for weeks. (As long as I check on it every few days to be sure it's not turned itself off.)Update June 2022 -- It's still working just the same. Most of the time, it does just what I expect. But about every 5th or 6th time I use it, after several hours (maybe overnight or a day later) it turns itself off (and battery voltage is about 12.7V or so). After that I have to leave it unplugged from AC for at least an hour or two, then when I hook it up again, all is fine and it'll work as expected until I need to drive my car again, maybe 10 or 14 days later. Except for the mysterious turn-off glitch, it's a good product. But because I don't have confidence it'll always have my battery charged and ready, I make sure to check voltage level a day or two before I need to drive somewhere.

So far I have been really happy with this battery maintainer. My Nissan Armada has a slight parasitic drain on the battery that will kill it if I leave it sitting for a week or so. I mounted this charger under the hood next to the battery and ran the power plug out the front grill. I then plugged it into a timer that only runs for about 4 hours a day. I purchased it in September, and so far it has worked through a very snowy winter where temperatures have gotten as low as -20 below zero. I don't think it has gotten water directly splashed on it, but I have driven through pouring rain and car washes that spray from all sides of the vehicle even from underneath.So far I'm impressed with it.Update, Sold the Armada and moved the charger to a small car we keep as a spare. It sat for most of the year through sub zero winter days, and started right up when I needed it last month. I bought a second one for my pickup and it has worked great. I ran into an issue where I killed the battery while trying to jump start an old diesel plow truck, (one of the cells had intermitant activity) and the charger indicated the fault. After getting a new battery it has kept my pickup charged through one of alaska's coldest winters. I'm ordering a third one for my plow truck as I only use it a few times a year.

Good charger, perfect for the job. I bought it to trickle charge my car battery and it does its job very well. Have had it for two months. It has been working perfectly fine.