#1 Tender For Batteries 12V Automatic Trickle Charger - 1.25Amp 5 Stage Battery Desulfator Maintainer & Conditioner. Perfect Maintainance Everytime By KeyLine Chargers USA

This thing is great .. while it lasts. I've gone through two of them now. The unit is *really* effective at reviving sulfated batteries. I had a car that didn't have a bell when you left the headlights on, so we were always leaving them on and draining the battery. It got the point where it would barely hold a charge. I used this unit and it brought the battery back to life. It was like brand new again.The only problem is that the unit died within a month. I figured I'd give it another try since the results were so good and maybe I just got a bad unit. But the next one died on the first use. I'm not sure what's up with these units, but it's really disappointing since it worked so well while it worked.

I put it on a lawn tractor battery at least 3 years old. The battery was dead from the winter when I got it. I put this charger on it, and the battery now will keep charge for at least a few days w/o being connected. (Seems to turn over as well after a few days as when freshly off the charger.)The only thing I wish is that the indication of what is going on was better. When first connected, it does a flashing light thing. You "can tell" what is going on by the duration of the light flashes. Maybe it is just me, but I am not good at telling 0.2 second long flashes vs 0.5 second long flashes.It would IMO be FAR better if it say flashed 3 times and then paused, flashed three times and paused, lather, rinse, repeat indicating one condition, and 2 flashes then pause, two flashes and pause, lather, rinse, repeat to indicate what it was doing when first connected, and the shore power connected.That brings up an irk. You have it with two lights indicating "floating" and then disconnect it from the battery so that the tractor can be used. Then return and it still has two lights. Reconnect it and it still has two lights. Did it enter charge mode for a short bit as other automatic chargers do? No clue cause there is no change. (I have two other automatic chargers. They give me some slight indication that "I am reconnected.") IF you disconnect the 120V shore power and reconnect the 120V power, THEN it goes into the "somewhat informative" (Is it 0.2 or 0.5 second? Who knows, not me) flashing lights for a bit.But it does seem to work on reducing battery sulfation, and keeps the battery charged and floating. :):)

Update 3/23/19: Seller responded within 12 hours of my email informing them of the missing cord with an email and shipping data on the missing part already in route to me. THAT IS CUSTOMER SERVICE!! Thanks to Diego, my missing ringed/fused cable arrived today. I can now officially appreciate the brilliance of this charger. No fake "steps" or overcharging with this charger. A rock solid performer that I can rely on to keep my concourse award winning italian steed charged with no fear of finding a dead motorcycle when I want to ride.No more boil-overs, over-charges, dry empty batteries for this guy. Already ordered 2 more for other candidates in the stable that could benefit from a premier class level charger such as this Keyline Charger. I can finally relegate my dispised collection of so called "maintainers" and "tenders" into the trash once and for all!! Thanks Keyline!!

Have a car which is rarely used and battery tends to run down over time from various usages in the car.When I received this I applied it to the battery of this car with a very weak battery due to non-use of car. This is the same one I will use it on for maintenance. Used clips and as such did not want to close the hood fully as that may affect clip placement As such, I just ran it during the daytime and after about 3 days of running battery was fully charged.Just finished attaching the other cable to some bolts on the battery post so that the battery area lid could be secured and the lid put back on and the hood could be safely closed.Only time will tell about its ability to safely maintain the battery. That is the only concern causing a 4 versus 5 star rating.Also could use one of the extension cords so that the wires from the unit would not be a trip hazard and I could leave all connected. However, Amazon shows out of stock for these items.

The overall charger seems OK, good value for the money (if it legitimately works as described).Here are my concerns:1) I can't tell if my unit ever does any other mode than the Bulk/Absorption and Float mode. When I hook it up to a battery, my unit does the 1s on/off pulse mode for 2-5 hours and then stays solid. I have NEVER, on the 5 batteries I put this on for 24 hours, seen this unit go into the De-sulfation mode ( 0.2 second on/off pulse).2) The fact that it has 5 different charging processes, but uses a single LED for all 5 is kinda worse that I expected. I would recommend people opt for a unit that has a LED for each mode, or an LCD. I think in a v.2.0 of this unit, they should stack micro-LED's along the graph printed on the face of the unit (above the 3 current led's) that align with the power wavelength picture thing (each mode) already printed onto the unit, that would be cheap and AWESOME!3) This unit gets hand scalding(ly) hot! Do not put it in a poorly insulated area (like under a car trunk hood) or on a carpet. The trapped hot air from this unit may cause it to have an even shorter life-span.

Connected this all winter long, via the fused ring terminals, to my rather large 27 form factor 12v automobile battery.I only turn the car over once a month to run the fluids thru the motor.....easy with the quick disconnect feature in the cabling.Can leave the fused ring cables connected to battery this way,as hold down strap and extremely tight spacingmakes charge maintainence a breeze; vs. the "old way" of dragging out the 20 year old Schumacher charger and charging overnite. We'll see reliability-wise....like the 5 yr. warranty!