Tenergy Smart Battery Charger for NIMH/NICD AA/AAA/C/D/9V Batteries, LCD Universal Rechargeable Battery Charger with Automatic Charge/Discharge Function & 5V USB Port for Digital Devices

Very nice. Looks a little nicer in person than in the pictures so that's cool. Super happy with the discharge function. I saved like three or four errored out batteries the first day I used this. Tenergy generally doesn't disappoint on the quality side and this one follows suit. The only weird thing is the LCD screen viewing angle. If you try to look at it at a 90° angle it fades significantly which is really weird. Looking at it from a 30ish to 45ish degree angle (more in front of the unit) provides perfectly clear views of the screen, not a huge deal but weird.

A bit fidgety for smaller double and triple A batteries. Fair price for the quirks. Charging speed is good, but drains quickly when left on the charger after finished. Small size works well.

Great!!! Charges my 10 to 15 year old nickel metal hydride AA & AAA batteries where my other two Chargers won't. When I put them in my other branded Chargers it will tell me there's an error but if I stick him in this unit they will charge. And you can do a cycle discharge with this unit where my other two units from Energizer and EBL will not. I like this charger a lot. It's got its issues with the display hard to read at certain angles but that's a minor thing when it actually does the job pretty good of actually charging older or batteries that are on their last leg. My only complaint would be that it's kind of hard to put the batteries in and out because of the spring mechanism but that's a minor thing.

Reviewing Tenergy T9688 (4 slot D-C-AA-AAA and does AAAA as well) Purchased 08 Feb 2023 All slots hold officially supported battery sizes tightly. (I have also used it for my tiny quad-A batteries and they work also.) I probably should give it 5 stars but sometimes I think people tend not to believe a review if 5 stars are awarded by a user. Charge time is moderate which is just what Tenergy advertises and it's just what I desire because the batteries last longer when gently charged. The discharge/recharge cycle works fine, too. I have no complaints. It's rock solid just like my other Tenergy charger. I also have a Tenergy TN162 8-slot AA charger since Juy 2021. It works fine all this time. No problems. The 4 slot T9688 has a 500 milliamp USB port. It's not worth much because practicalliy nothing functions on that little bit of power these days. The USB port only works when the charger is not charging batteries. I have a low draw USB lamp that uses 100 milliamperes. I plugged it into the USB port just for fun. The light plugged into the USB port comes on. If you then charge batteries, the light goes off...until the battery charging process finishes then the USB port is automatically re-energized and my lamp comes on again. So, the USB port could be used to light a lamp to let you know it's done charging. Or, maybe Arduino or Raspberry Pi users would want to use that port to trigger something fun when the battery charge process is done--like send an emaill or activate a buzzer? I don't know what else to say. The Tenergy chargers just do what they are supposed to do and they feel substantially weighted like high-quality materials probably comprise the devices. I plan to get another 4-slot Tenergy so I'll have 2 of the 4-slot models because my aged Vanson BC1HU 4-slot chargers are getting very old and smelling of phenolic overheat...so the young strong Tenergy chargers are ready to step in and take over and keep me powered up. Thank you, Tenergy.

Though I can't attest to the durability of this universal NiCad/NiMH battery charger, I can say that it works as expected and seems to be well built. Some reviewers have complained about difficulty reading the illuminated blue readout window, but I haven't found the limited viewing angle to be a problem. Otherwise, the spring-loaded contact arms are sturdy, and it's easy to load and unload batteries. The machine automatically detects the chemical composition of each battery and charges accordingly. Because I use NiMH batteries, I haven't tried the "Discharge" feature, which I assume is useful for NiCad cells that get lazy and don't hold a full charge if you don't discharge them every few months, or as needs warrant. My only gripe at present -- and it's a minor one -- is the lack of rubber or plastic feet on the machine, preventing it from scratching a wood countertop. I fixed the problem by attaching four self-adhesive pads available at the Home Depot, but I think Tenergy should include these. Otherwise, I give this charger two thumbs up and expect it to deliver many years of faithful service...

This charger works, but I’m not fully satisfied with the performance. I used it with the same brand rechargeable batteries, and they tend to get quite warm during charging. Also, the charging speed is pretty slow—it takes much longer than I expected. The display and functions are decent, but the heating and slow charging are a bit concerning. Overall, it’s usable, but I was expecting better performance

This battery charger has all the features I've always wanted at a midrange price. You can put a different size battery in each bay.AAA battery size in one bay and a AA in the next bay a C battery in the next bay and a size D in the other bay and you will be fine. You will have to wait for the D size battery to discharge before the charge function starts which takes a few hours but you get how independent each bay is... you can also put a different brand of AA battery or AAA battery or what ever size battery you want in the charger.. now I charge all my AAA then charge all my AA then charge all my C batteries ect...ect...I'm just organized like that but you get how mismatched you could be if you had on empty bay and wanted to fill it with some other size.. the 9 volt is the only one that takes up more space than the rest.. the charger also let's you know if a battery is bad or has come to the end of its charging life.. over all this is a good charger for 35 bucks... I recommend this midrange charger.. you can always pay more for more battery capacity or more features or a heavier duty charger build..this charger is made of plastic but with proper handling this charger should last for years before needing to be replaced.... but for my needs this will fit the bill..I give it a 5 star rating

Product performed great, had functions that I did not expect. (ie the discharge function) Used the charger to update old battiers that use to take over eight(8) hours with the old charger, the new charger charged the battiers in less than three(3) hours

Please beware that this comes with a US style plug so not suitable for uk. The photo does show it but it is not obvious.