CTEK - 40-206 MXS 5.0 Fully Automatic 4.3 amp Battery Charger and Maintainer 12V

Jay Leno talked about this unit on his show and praised it highly, he's a real car guy plus I highly doubt Jay's endorsement could be bought. I plugged mine onto what had been a healthy 12V car battery that tested at only 11.6 volts when resting. Overnight, the charger went through all 8 steps of charge/test and had a green light. Now the battery tests at 12.6v Maybe any other charger would have restored it that well but this thing puts the battery through a lot of steps to improve and insure it's 'health'. Highly recommend. High quality, fast charge, great power, easy to attach, LONG cord, easy to use basically plug'n'play. The instruction manual however, not so great. I viewed some youtubes to make sure I understood the various functions, there are plenty of them, turns out this is a very popular charger for real car guys.

This battery charger/maintainer works excellently with almost no effort to recharge a weak battery or maintain a battery in cars that aren't driven regularly. This is especially important in colder weather as the charge can drop enough to be unable to start the vehicle. This almost happened to my 2011 BMW 535i Xdrive 95Ah battery after not moving it for 2 weeks mid winter. I got several low charge warnings but thought they would go away once I drove a bit, but trips were far and few between. The charger power cord is hard wired, and the output leads have a fast clip connector at the far end to plug in either the alligator clip ends or 1/4" eyelets for a more permanent connection to make frequent charging easier. Both the power cord and the output leads are 6' long for a total of 12' plus another 18 inches for either the alligator clip or eyelet connectors, so there's plenty of length to position the charger where you want. The clips are spark free and have polarity protection so you don't have to worry about those when making your connection. Plugging the device in starts it in standard vehicle battery mode. Other modes include motorcycle for smaller vehicles, AGM for those batteries, and a reconditioning mode to restore full capacity to batteries that have lost some charge capability. From almost dead, it took about 28 hours to go through all 7 phases of charge. Patience is the way to go here, don't check often, especially if you have to open a door or hood to do so. I found it best to leave it under the hood with it slightly ajar and check every 4 hours or so. Resist the urge to unplug it because you think it's not progressing. It is. Even in cold weather it will get your battery back in great condition with little more than the press of one button. Highly recommended.

Love the CTEK chargers and have not had one problem with them or any car they have been on. Will charge any battery has a low rate of charge so will not damage electronics in cars and a fraction of cost of OEM chargers. Weight is irrelevant but it comes with a carry bag.

Been using this in my 2021 BMW 228 while it is stored for winter. It is user friendly and easy to use. I can unhook it and start up no problem and it is maintaining the battery well. No complaints and much more affordable than the BMW branded battery packs which I hear are made by the same company

3rd Update: My CTEK has now gone to Step 8. I can hear a faint, ticking type of sound coming from it, like I heard in some earlier steps. So,...it works exactly like it's supposed to.🥹 I love it!🥹 2d Update: My CTEK is still keeping my battery charged, at Step 7. I keep the hood open just a bit, and occasionally lift it to check on everything, as I am using the clamps to connect my CTEK. I also check my CTEK daily. I have it sitting on a table near my outlet and my vehicle. I did purchase the additional extension cord from CTEK, but haven't needed it. The only cord that seemed a little short to me was the cord that the clamps are connected to, but it turned out to be plenty long to reach my negative ground point bolt, and to connect to the Comfort Connect cord that goes to my CTEK. CTEK has a video out showing how you can make the clamps cord a little longer, but I think its best to wait and see if you need to do that, because once you pull it apart, you can't really undo what you've done. It was a little awkward for me connecting everything by myself the first time, and I didn't want to drop anything - especially inside my engine compartment - so, I put everything, but the clamps cord in a tote bag and sat it in a secure spot under the hood while I very carefully connected the clamps. I think the first time I did this, I even kept my arm inside the totebag handles. Laugh all you want, but better than fishing it all out of my engine compartment.🥹 Update from Earlier Review Today: It is early afternoon, and my Ctek has now reached Step 7, and is showing a green light at that step!😊 No more dead batteries for me!😊 Original Review: I think this is a fantastic device, and I am so happy I found out about it!😊 I had no idea there was something out there like this. It is now charging my vehicle at Step 4, and I am confident it will continue thru all the steps. When I first hooked it up, my vehicle battery was down to 3.6. I found this out when I jumped it with a jump box, something which I knew nothing about either. I started out looking for jumper cables.😊 So, this device would not go past Step 1. The solid red error light came on, and the green light stayed on. I unplugged it, and reconnected the cables to my battery, and plugged it back into the wall outlet. (I thought maybe one of the cables had moved when I gently lowered my vehicle's hood, and left it open just a little bit. But, that was not the case.) The red light did not come back on, but the green light did, and it did not go back to Step 1. Since the green light came back on, I figured my Ctek was good, and that my battery was just too low for it to charge. So, I jumped my vehicle, (and it immediately came to life, as it is a newer one) and drove it for awhile. I then reconnected my Ctek - after resetting my BMS (Battery Management System), and locking all my vehicle doors, per my vehicle manual - and it immediately went to Step 2, with the green light on. Sometime overnight, it went all the way to Step 4, and I am so very happy!😊 Thank you so much, Ctek!😊

Purchased this in 2018, and has worked well except for a flakey mode button the last couple years, that required very hard repeated pushes to activate. Saw YouTubes on how to clean/replace switch, but they required cracking into unit, compromising water resistance. I fixed mine by cutting through and around the mode button plastic label, lifting out the 1/2inch circle, then popping off the black button underneath. I then squirted some plastic-safe contact cleaner on the surface mount microswitch and repeatedly pushed to work it in. The switch then returned to normal functioning and selected modes easily. Applied clear vinyl tape over reinstalled black button and hole, extending over black label and trimming with razor to edge of label. You could try to save the mode button cutout and install under tape, but I just used a white Dyno label for the now working black mode button. Except for this one switch flaw, it has worked great to charge and rejuvenate car, mower and booster batteries.

Great battery charger and maintainer! It immediately identified a weakness with my battery and fixed it. Love this thing! Wish I had bought it sooner. I'm hoping it will extend the life of my battery. Highly Recommend this....

I've used a CTEK to maintain the battery in the Vette since 2017. Wanted another, same model, but apparently that has been replaced with this unit. Well, it works great. Just bought a new AGM battery and even though it came out of the box at 12.83 VDC, I used this new CTEK to see if it might "energize" it. It did, After several hours, the new CTEK went through its routine and actually brought the new battery to 13.15 VDC. It's been 3 days since I removed the CTEK and as of today, the new AGM battery is at 13.10 VDC. Good quality, works great. If you have a questionable battery, try one of these. You might revive what you think is a battery that needs to be replaced. Sure, it takes time but that's how the process works. 5 stars all day long and cheaper than a new battery!