Schumacher ElectricDSR121 ProSeries Car Battery Charger - 250 Peak Amps - 12v Battery Charger - Fully Automatic Battery Maintainer, Engine Starter + Auto Desulfator - for Automotive Shop/Dealer Use

I was really looking forward to having a replacement battery charger for the 30 year old 250 amp craftsman I’ve been using to maintain a small fleet of dump trucks. Now that I only have a couple pieces of construction equipment, I wanted to upgrade to a newer charger to maintain the equipment that doesn’t run every day. I had a repair scheduled with a mechanic that needed a battery charger.Brand-new out of the box, noticed that mysterious screw and a piece of broken plastic at the bottom of the box which had no packing foam and just thin cardboard.No power to the unit. Looking closer, the mechanic and I found that it had a major crack in the top part of the control unit and had at least six wires that had been shaken loose or unplugged. This delayed my repair, cause more downtime, and had to go to a local automotive store to get a 200 amp charger. Very disappointed that this expensive unit has such poor connections and thin plastic.IMO, this unit is not suitable for mobile mechanics in and more for a white glove garage/shop.We did manage to get to turn on the unit but someone had crossed the wires and the off switch gave power to the unit!I am going to begin the return process and will include photos including the serial number in case someone is re-sold this unit.I will update my review during the process but currently Amazon is requiring that I pay for the shipping to return this item for some reason???Cv 7/22/22 10:30am

Love this charger. It’s expensive, but it packs a punch!!! Thinking about getting another for the shop.

The media could not be loaded.  Schumacher customer service is great, once they realize you actually know what you're talking about.My units flash programming mode didn't work out of the box but they got me taken care of. Overall it's a great charger, the desulfate mode works and brought back an AGM battery that was over 10 years old.Update: The flash programming mode works, however the current output is slow to respond and not stable at all. Like if you suddenly remove a load the voltage jumps a substantial amount, if you add a load it drops and is super slow to respond. I've made a video and started an exchange hoping this unit is just defective. I will update my review when I have the replacement unit to compare how they behave. If the replacement unit has the same voltage regulation problem, this will be a huge issue since I've gotten the voltage to jump up above 19 volts while connected to a good fully charged battery! During flash programming you frequently cycle the ignition and fans and lights and other loads can cycle. Just imagine if it dips the voltage as a pcm is initializing, it could brick it. I emailed Schumacher but have not received a response after a few days so I decided to post this review and take them out of the loop.Update #2: The replacement unit arrived which I immediately tested, sure enough it also has voltage swings although not as bad as the first unit. As of right now I am going to recommend avoiding the unit and purchasing something else, a shame really. The unit needs to respond faster to voltage changes, I worry that vehicles that monitor voltage during flashing like BMW might kick you out of the flash due to how long it takes to recover from a voltage drop. I also dislike the fact it has no current display when in flash mode, you have no idea how many amps you're pulling from the unit. I expect more from the DSR series, especially considering the cost of this unit.

I bought open box as it was a better value. Was advertised as near new. Arrived with surface scratches from prior use, and the the panel was greasy. Put it to use to charge a car batter (12V). Started fine. Checked after an hour, and it had turned off without fully charging the battery. Would not turn on again. Also tried to test on another car battery - no response. Returning it to Amazon. Should have trusted reviews with nearly 25% one start ratings.

No paperwork at all! Instructions Not Included, Warranty Information? No. And why are the 4 Screws the tamper proof type? You could have included the torx bit to fit that.

It works well.

Just had the opportunity to try out my new charger. Unfortunately, it was dead out of the box. I will be addressing this issue with the seller and Schumacher...UPDATE: 1/10/2020 - Finally received RMA authorization 8 days, not the 1-2 days promised, after waiting 30 min for customer service. Their warranty requires purchasers to pay shipping without consideration of reimbursement if they determined its a manufacturing defect. Cheapest shipping costs were estimated at $250 round trip,Fortunately, I have a borescope and found that a wire had never been connected (no scratches on terminals). i connected the wire without disassembling anything in 5 min. Now product functions properly.CONCLUSION: Schumacher did not test this product prior to shipping. I would have paid $250 because Schumacher does not have control of their quality / manufacturing process.I will not be purchasing or recommending Schumacher products to all my contacts at the major automotive OEMs that I support professionally...

This thing is useless and just to make it more complicated, there’s zero directions on what is what on icons or how exactly to set it for different scenarios. You cannnot tell which setting is boost/start and when it’s 10 below outside, last thing you want to do is take an online course to try to figure it out. Even when you do, it’s still junk. Doesn’t supply the charge needed.

like the 24 volt dislike I hope the switchs last in it wheels could be better

This looks like a great unit. But they didn't include the power cord in the box with the charger. I am hoping that some one can send me the cord, or another machine with a cord.