My old Schumacher charger lost a diode and started to ruin batteries instead of charging them, so I hunted around and found this.

In the almost 20 years since I bought the Schumacher, battery charging has been taken over by microprocessor-controlled chargers that do multi-stage charging, desulfation, etc. It's nice to have a charger that will automatically transition to a float charge once the bulk charging is done. It's handled every battery I've thrown at it, from automotive to lawn tractor to sealed lead-acid out of a backup power supply. That's the good part.

The bad part is that you won't rescue a really dead battery with this. The battery in the backup power supply was stone dead (like less than 8v-- really REALLY discharged). This charger refused to charge it, claiming it was defective. Since I had nothing to lose, I hooked it up to a battery tender, which is just a low current trickle charger meant to keep a stored battery from discharging. After about an hour the battery tender had brought the voltage up enough to where the charger would recognize it, and it charged the battery without further complaint. That battery probably won't live too long after all the abuse it's received, but since it's only used for short periods of time when the power goes out, it shouldn't have to.

In short, this charger works fine under most circumstances, but be aware that it does have limitations when trying to resurrect heavily discharged or neglected batteries. Since I end up doing this far more often than I really should, I ended up putting a new diode in my old Schumacher charger. I hardly ever use it any more (this new charger really does do a nice job), but there are times when you just need a "dumb" charger to get the job done.

After reading the bad reviews I was was not going to buy unit to use on my bran new trolling battery. Cost and features won out and I purchased it. It arrived in good condition and I proceeded to attach the charger to my new battery. The unit stated my battery was 100% but in a couple minutes it started bulk charging at 60%. That scared the hell out of me (because of the bad reviews) and thought, I have a mower battery that is near dead, I'll blow that one up instead!!! Hooked up the mover battery and the unit reported 0% after a couple minutes it started bulk charging at 60%. I figured OMG its bad and doing the same thing as one of the bad reviews!!!! I'm returning this POS asap. But i left it charging the mover battery. went out to check on it within the hour and found it in absorption phase and reporting 10 amp charge but it was clocking down the amps every couple minutes. 10, 9.9, 9.8, 9.7 and so on. after about one and a half hours latter i went back out and found it at 1.9 and still counting down. I checked the battery at this point to see if it was hot or had problems! NOPE all good. The unit finished, said the battery was fully charged and went in float mode. I tested the battery with another tester and sure enough it was fully charged and every thing was good. So i thought I'll do my deep cycle and watch it. Anyways It finished topping off the deep cycle within an hour and I used it yesterday for 6 hrs. fishing and the battery was powerful as it should be for a new deep cycle battery. I had used less juice then what it needed for being bran new. THIS CHARGER IS WICKED GOOD, I love it.

Charger quit working after power went out and came back on. I was using it in float for marine battery.
I contacted seller and they were very helpful. They sent me out a new charger. I use this charger for all my needs. I charge my boat after every use, it has (2) gp24 batteries. I will leave it on and as soon as it completes the charge it automatically goes to float. I charge my small lawn tractor battery every year at 2 amps overnight. I have jumped many trucks and cars that have sat in my shop with great results. The only drawback is it will not bring back a battery below a set number of volts. Once the battery is above the I switch to this charger and put it in repair mode. I have had it bring back many "dead" batteries. I highly recommend this little charger. It is light, easy to use, safe, and very dependable.

I ordered this a month ago with a specific battery problem in mind. I chose this one because of it's advanced reconditioning mode. If you've studied up on batteries at all, there is a process called sulfation that ends the lives of a lot of batteries. This reconditioning mode promises to reverse that. The battery I ordered it for is a big truck battery and this tool cost exactly half of what they battery cost, so I figured I've give it a try (I needed a decent battery charger anyway so it was not much of a gamble if it worked at all)
The battery is question was in a junk vehicle that had only been jump started once in the last six months. The battery was bad enough that it wouldn't stay running unless you left the jumping battery attached and leaving it on the charger long term left it totally dead still. It was so bad, this unit didn't even recognize that a battery was attached when I hooked it up! So i hooked the battery to a jump box for about 10 minutes so that it had enough voltage to seem like a battery and then moved it over to this charger and started the reconditioning process.
This is a long process and I left it sit for a day to do it's thing. I stuck it back in the truck and it fired up immediately like a good battery should. I let it sit first for a week and started it up again fine and then for 3 weeks and just started it yesterday. The fix is real. This battery is perfectly good now. The temperatures here have been in the 90's too so it's not being babied while it's sitting.
I would definitely get one of these if you are a do it yourself type person at all. I saved the cost of this device on the first battery I tried it on. I'm going to hook it up to our little camper and try the maintainer mode next to make sure the battery is ready to go.

I bought this charger in July and returned it in August.

Pros:
1. Easy to use. Hook up the cables, plug it in and it does it's thing.
2. Light weight
3. Led screen easy to read

Now for the concerns
1. On one battery, the battery started over heating while going through the repair/charging cycle.
2. On the last battery, the positive cable clamp began to melt while charging. Reason for the return. Maybe plastic is not the way to go with these clamps.
3. Ampeak customer service never responded to 2 separate inquiries.
4. Amazon customer service was helpful, but a bit flaky. I spoke with three customer reps, who provided different stories how they would rectify my issue. Two reps told me I wouldn't need to return the damaged unit and they would have another unit sent out. That did not happen. Finally on the 3rd attempt, the rep, who I believe was a supervisor, said I would have to return the unit and they would refund my credit card. From there she told me I would have to reorder the unit.

Overall, I did like the charger. I haven't decided if I'm going to buy it again yet and eventually change the clamps to metal ones.