Trickle Charger Car Battery Charger Automotive, TOPDON T4000 4A/1A for 6V/12V for Lead-Acid/Lithium ion Batteries, Auto Smart Battery Maintainer Desulfator with Temperature Compensation,AGM,Deep Cycle

2024 UPDATEThey have updated this Amazon listing to be a different version than what I bought in 2022.Mine was longer, gray rather than black, much better looking, and with probably better lights/display.Who knows whether the guts were changed for better or for worse.Mine still works great, I could tell a long list of stories of what I've used it for successfully.ORIGINAL 2022 REVIEWIt is very simple to use, and worked well on everything I used it on. Those included a car battery removed from a car (I didn't have a battery in any of our cars which needed charging or reconditions) which was half dead, having been removed from a car a couple of years earlier. I didn't do the amount of experimenting to figure out whether it improved the battery, but it did charge it properly, and it did seem to go through its desulfation cycle just fine. Last fall, I had a garden tractor which hadn't been used since the relative it came from died a couple of years ago, maybe well before that, not sure. The battery was drained to a point where I'm surprised this figured out it was a 12V battery. It charged it up well enough to use the tractor to mulch and blow all the lawn leaves into the woods. Again, not sure if the desulfation cycle did anything constructive, but it probably did, because I thought the battery would need a jump even after charging and desulfating a couple of times, and it didn't.Last but not least, I used it to charge a half-charged LiFePO4 50Ah battery I bought to use like a larger power station than I already had. I'm not sure whether I clicked the mode button to get it to Lithium, or it self detected, but either way in a couple of seconds the Lithium mode light was on and it did apply the correct charging voltage at each stage of charging.It is bigger/heavier than my very old Sears 3A computerized automatic charger, but it's still compact and light for a battery charger, sort of like an oversized laptop power supply brick. The plug, cables, clips and everything are of perfectly fine quality, more than sufficient for a 4A battery charger.Happy with the purchase. I'd been tempted to get the 8A version, but wanted the versatility to charge smaller batteries at 4A without having to drop down to just trickle charging. This also means you can run it off a pretty small power station (like my 300Wh one, or smaller), if you are on the road without access to an outlet. Campers and RVers should have a charger like this, to be able to charge the vehicle battery off the house batteries/inverter, even if their system for doing that goes bad. Likewise, a little inverter, even powered by the cigarette lighter 12V outlet can turn this into a poor man's DC-DC charger to manually charge the house batteries while the vehicle is on. A bigger charger might blow the 10A fuse on those, especially if you're running a laptop off the same 12V outlet. This gives you a better shot, but don't forget to carry spare 10A fuses anytime you rely upon the lighter 12V outlet.

The media could not be loaded. I have an older vehicle I don't drive very often, and it tends to drain the battery over time. I bought this battery charger to keep it charged, and so far I am very impressed. It reported the battery was at 50% when I hooked it up (see video), and it fully charged it in a few hours. It also has a maintenance mode that looks like it trickle-charges a full battery to keep it topped off, so this is perfect for my application. What I hadn't expected, though, was that it also has a desulfation feature that breaks down the sulfates in the battery to prolong its life - a feature I have only seen in more expensive chargers! The unit itself feels very solid and well-made, and the wiring and connectors are good quality. Even the packaging makes it feel like a quality product. Overall, I am very happy with this little charger.

I can't give this charger 5 stars because the "repair" function does not appear to do anything. I tried it on three different batteries and did not see any improvement on any of them. I have a battery checker that display checks the capacity, charge, and internal resistance. Not a single parameter changed. Other than claiming that it can repair batteries, it is a good charger. I honestly wasn't expecting the "repair" function to do much, but if its advertised that it can then it should at least do something.

This simple and small unit managed to recharge my battery which had so little charge that it was effectively dead to full power. I was surprised at just how well it worked, given that most chargers or jump starters will not work if the battery is entirely spent, and I mean close to zero charge.Pleasantly surprised. This unit saved me from buying a new battery which would have cost me at least $350 and more like $400 to have it installed. Now that I know I can reliably revive my battery, I won't hesitate to charge it up again.

I have owned this device for over a year, and when I needed it to charge a standby battery, it failed to do so. I followed the instructions in the manual and watched several YouTube videos to ensure I was using it correctly. However, it seems I may have a defective device. I trust the company will honor their three-year warranty, and I plan to contact them for assistance.I will update my review as soon as I have more information.Update: Topdon honored their product warranty and informed me that this model was discontinued, so they refunded my money—five stars for Topdon for honoring their warranty.

I wanted to like this charger, and was happy to get it and put it to use. I have several motorcycles and atvs and always need to charge batteries. However, this Topdon unit proved very frustrating. It has a habit of giving up while charging. You’ll put it on a battery and come back the next day to find it didn’t charge it. Also, the repair function never worked. I used it per the instructions on two batteries but it never did anything. I used one of my other chargers to repair them and they both came back to full charge.Bottom line, this thing is too finicky and ends up wasting your time when you need to get things done. Wish I had returned it but I missed return the window fiddling around with it.

Has been so worth it. Have used this many, many times.

The Topdon 4000T Battery Charger/Maintainer is everything that I wanted in this product, Works great. I did extensive research pri to making a purchase, the more research I did the more the Topdon 4000T proved to be the battery charger I wanted. After receiving it I read the operation manual and installed the unit with confidence on my new Jeep Cherokee with ease, very easy to use indeed.I appreciate a well built product with the latest tech support.Thank You,Scott A Fike, Sr.