The lowdown — A smart charger that's thought out and built well, recognizes an unusually wide range of batteries, charges them with precision, and even tests them if you want.
Rechargeable batteries are more fickle that a lot of us realize, requiring bespoke charging methods and careful cutoff to prevent overcharging and eventual destruction. Tenergy TN456 answers the call. One reason I like it so much is that it recognizes a wider range of batteries than similar devices. For instance, I use "Sub-C" NiMH cells, not common at all, in a wireless soldering iron. Only the TN456 recognizes and charges these correctly.
And it covers three battery chemistries instead of the usual two. NiCd and NiMH are par for the course, but the TN456 accepts Li-Ion as well, a chemistry with a completely different charging protocol.
It is well made and exudes a feeling of quality. The backlit LCD screen, highly legible, cycles through various data items as you press the Display button. This smart approach allows the numbers to have a much larger font. The four charging bays, each with their own display, take sizes from AAA all the way up to C, although in case of larger diameters only in a mix as the picture shows. This is a small trade-off against its compact size. It handles from 35 to 70mm in length.
(If your battery is shorter than 35mm, say 2/3 or 1/2 AAA, then stack a few dimes in between to create spring tension and contact.)
The TN456 also features a 5V USB 2.0 output, a rare yet handy extra.
It has two charging modes: "Charge" and "Test." Both modes will lead to a charged battery but Test will also tell you its capacity. To achieve this it tops off the battery first, then discharges it completely to obtain its capacity in mAh, and finally charges it once more. These extra steps take a lot longer than charging alone but are the only way to get an accurate number. If it is near rated capacity then your battery is in good shape.
Note that simple charging will also produce a mAh figure. But this one overstates capacity because charging consumes more energy than what gets stored.
You can select the charging current in mA for each bay. The back panel suggests optimal current versus battery capacity. That's a very nice touch since it answers the question asked most often. It also shows how the manufacturer cares about optimal use of its device. The TN456 reverts to its lowest charging current of 300mA if you choose not to adjust. Since all bays are independent, it is not necessary to insert batteries at the same time or even on the same charging mode.
If your particular battery is not listed then a reasonable rule of thumb is to charge at a current around 0.5C, where C is the stated capacity in mAh. So if the battery is rated at 1,000mAh then charge at 500mA. A bit lower, say, 0.3C will increase total charge but takes longer. A much lower current makes it more difficult for the charger to sense proper cutoff, inviting the risk of overcharging. Anything much higher can heat up the battery too much, shortening its life. As failsafe the TN456 monitors temperature in the battery bay and shuts itself down if things get too hot.
Finally, for enthusiasts, this charger indicates internal resistance in milli-ohms (mR), another uncommon feature. The lower the better. Anything below 100mR suggests a healthy battery. Knowing internal resistance and measured capacity helps you assemble matched battery sets. Since this resistance goes down with charging it is best to obtain it after starting an extra cycle. The batteries are already charged so the charger will stop quickly by itself. No worries there.
NiCd versus NiMH — NiMH cells are almost always the preferred choice because, being a modern development, they simply work better. For instance, their energy density is much higher than that of NiCd. This means they pack more mAh in the same space hence last longer before needing a recharge. And NiMH batteries suffer fewer so-called memory effects that irreversibly reduce capacity over time. They are also less polluting since they do not contain heavy metals.
The one area where NiCd cells still have an advantage over NiMH is in applications requiring very high discharge rates. This is almost never the case in consumer electronics. The device would have to mention it.
Li-Ion cells put out a different voltage of 3.7V per cell. Hence they are in no way compatible with NiCd or NiMH applications. While they have the highest energy density of the three chemistries, they also demand the most careful use. Running them to empty will cause damage. Overcharging can lead to conflagrations. That's why it is best by far to select Li-ions with built-in undervolt/overcharge/overheating protection.
Summing up — there are several offerings in the category of premium smart chargers. They tend to share features such as the test option I highlighted. What sets the TN456 apart is widest range of recognized batteries, three chemistries instead of two, protection against overheating, a USB port, build quality, compact size, more actionable data, and its superb backlit LCD.
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Product Description
**Only recharges a max of 2 C size batteries at once.
Individual Channel Control
- TN456’s four channel select buttons let you choose a specific battery and change its setting (mode / charging current) at will.
5V/1A USB Charging Port
- In addition to charging your batteries, TN456 also has a 5V USB port that charges your portable devices (such as your smartphone) simultaneously.
- Charge Mode: Charges your batteries at the desired current (300-1000mA).
- Test Mode: Tests the capacity of your batteries.
Backlit LCD with Display Options
- With just one button, easily toggle between display options to view charge/discharge capacity, battery voltage, charge /discharge current, internal resistance, or elapsed time. The backlit LCD display lets you read easily, even in the dark.
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Guide for using TN456 Intelligent Battery Charger
Tenergy Corporation
Reviews with images
Amazing if you need to do NiCd+NiMH+Li-ion of various sizes (incl C) or want to customize current
As the description and all the other reviews make clear, this can charge virtually any standard "small" consumer rechargeable battery, from A, to AAA, to AA, to sub-C, to C... whether NiCd or NiMH. It can even handle various Li-ion batteries. It also allows you easily customize the current of the charge independently to each battery slot -- from 300mA (default), to 500mA, to 1000mA -- and has clear guidance on the back (bottom) that suggests when to do so. On top of all that, it has a USB-A port that outputs 5V 1A, which is less than you'd want for any kind of modern device's USB charger, but still a nice touch. To power the charger itself, it has a wall-mount power-brick that is big, but still takes up less space (on the outlet) than a typical 4-AA wall-mount charger would.So all of that is great, but if you just want to drop your AA/AAA batteries into a charger and know when they're done, you DO NOT need this charger; get something cheaper like the "Tenergy TN480U 8-Bay LCD Display Fast Charger for NiMH/NiCD AA AAA" instead (which I also have). I love that thing because it can be powered by micro-USB or USB-C and always does 250mA for AAA batteries and 500mA for AA batteries. No thinking, no babysitting.Since you're still reading, you probably are interested in the discharge/test function. That's literally the only reason I bought this and it's also the most disappointing thing about it. Just like everything else, the test function can be triggered at any time for any battery slot independently of the others. Once you do it, it charges the battery to full, then discharges it completely, then charges it back up again -- all the while showing stats. When it's done, you're most likely interested in the total mAh value -- e.g., to see if those old batteries of yours still come anywhere close to their advertised capacity of 2300mAh.I tested a dozen AA and AAA batteries, both old and new. You can choose whether to use the default charge/discharge rates or to customize it. I stuck with defaults all the way. The process worked well and I was really happy. I used a sharpie to write numbers on all the batteries.Then it occurred to me: I have no idea if these numbers are correct. So I proceeded to re-test a bunch of them .... and that's where disappointment finally creeped in -- there was a difference of +/-100mAh for each battery. So in the end, my conclusion about the test feature is this: either the device is simply not that accurate enough to reproduce it's own results consistently, or battery capacity is really messy science. The discharge/test feature should help you suss out any very low-capacity batteries, but if you're just trying to optimize (e.g., to put your 3 2000mAh batteries into the same device and your other 3 1900mAh batteries in another device), it's not worth it.
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Reviewed in the United States on February 4, 2020
Reviewed in the United States on April 2, 2024
Reviewed in the United States on September 10, 2023
Reviewed in the United States on June 30, 2023
So all of that is great, but if you just want to drop your AA/AAA batteries into a charger and know when they're done, you DO NOT need this charger; get something cheaper like the "Tenergy TN480U 8-Bay LCD Display Fast Charger for NiMH/NiCD AA AAA" instead (which I also have). I love that thing because it can be powered by micro-USB or USB-C and always does 250mA for AAA batteries and 500mA for AA batteries. No thinking, no babysitting.
Since you're still reading, you probably are interested in the discharge/test function. That's literally the only reason I bought this and it's also the most disappointing thing about it. Just like everything else, the test function can be triggered at any time for any battery slot independently of the others. Once you do it, it charges the battery to full, then discharges it completely, then charges it back up again -- all the while showing stats. When it's done, you're most likely interested in the total mAh value -- e.g., to see if those old batteries of yours still come anywhere close to their advertised capacity of 2300mAh.
I tested a dozen AA and AAA batteries, both old and new. You can choose whether to use the default charge/discharge rates or to customize it. I stuck with defaults all the way. The process worked well and I was really happy. I used a sharpie to write numbers on all the batteries.
Then it occurred to me: I have no idea if these numbers are correct. So I proceeded to re-test a bunch of them .... and that's where disappointment finally creeped in -- there was a difference of +/-100mAh for each battery. So in the end, my conclusion about the test feature is this: either the device is simply not that accurate enough to reproduce it's own results consistently, or battery capacity is really messy science. The discharge/test feature should help you suss out any very low-capacity batteries, but if you're just trying to optimize (e.g., to put your 3 2000mAh batteries into the same device and your other 3 1900mAh batteries in another device), it's not worth it.
Amazing if you need to do NiCd+NiMH+Li-ion of various sizes (incl C) or want to customize current
Reviewed in the United States on June 30, 2023
As the description and all the other reviews make clear, this can charge virtually any standard "small" consumer rechargeable battery, from A, to AAA, to AA, to sub-C, to C... whether NiCd or NiMH. It can even handle various Li-ion batteries. It also allows you easily customize the current of the charge independently to each battery slot -- from 300mA (default), to 500mA, to 1000mA -- and has clear guidance on the back (bottom) that suggests when to do so. On top of all that, it has a USB-A port that outputs 5V 1A, which is less than you'd want for any kind of modern device's USB charger, but still a nice touch. To power the charger itself, it has a wall-mount power-brick that is big, but still takes up less space (on the outlet) than a typical 4-AA wall-mount charger would.Reviewed in the United States on June 30, 2023
So all of that is great, but if you just want to drop your AA/AAA batteries into a charger and know when they're done, you DO NOT need this charger; get something cheaper like the "Tenergy TN480U 8-Bay LCD Display Fast Charger for NiMH/NiCD AA AAA" instead (which I also have). I love that thing because it can be powered by micro-USB or USB-C and always does 250mA for AAA batteries and 500mA for AA batteries. No thinking, no babysitting.
Since you're still reading, you probably are interested in the discharge/test function. That's literally the only reason I bought this and it's also the most disappointing thing about it. Just like everything else, the test function can be triggered at any time for any battery slot independently of the others. Once you do it, it charges the battery to full, then discharges it completely, then charges it back up again -- all the while showing stats. When it's done, you're most likely interested in the total mAh value -- e.g., to see if those old batteries of yours still come anywhere close to their advertised capacity of 2300mAh.
I tested a dozen AA and AAA batteries, both old and new. You can choose whether to use the default charge/discharge rates or to customize it. I stuck with defaults all the way. The process worked well and I was really happy. I used a sharpie to write numbers on all the batteries.
Then it occurred to me: I have no idea if these numbers are correct. So I proceeded to re-test a bunch of them .... and that's where disappointment finally creeped in -- there was a difference of +/-100mAh for each battery. So in the end, my conclusion about the test feature is this: either the device is simply not that accurate enough to reproduce it's own results consistently, or battery capacity is really messy science. The discharge/test feature should help you suss out any very low-capacity batteries, but if you're just trying to optimize (e.g., to put your 3 2000mAh batteries into the same device and your other 3 1900mAh batteries in another device), it's not worth it.
Images in this review
Top reviews from other countries
NeuroEmergent
Feature-packed charger
Reviewed in Canada on April 18, 2017
NeuroEmergent
Reviewed in Canada on April 18, 2017
The TN456 intelligent charger is excellent. It features an easy to read LCD display, multiple charging currents, and 4 slot capacity. I charge my AA's, AAA's, and 18650's without issue. You can charge 1 by itself or up to 4 completely different types of batteries at once. It also has a USB slot to charge phones. As far as I know, this isn't standard on most other battery chargers (such as the Nitecore D4). Lastly, it has a test function, where you can determine the true mAH rating of your batteries.
•• A little backstory + Differences Between Tenergy and Nitecore ••
Recently, I began using medical marijuana to treat a couple of issues, ranging from herniated disc pain to lingering concussion symptoms. I know, I know. That's how most battery charger reviews go, right? The point is, I acquired a vaporizer that requires 18650 lithium-ion batteries. Until a few months ago, I didn't know these monstrosities even existed. Unfortunately, the single battery charger my unit came with has a high failure rate. It also charges one at a time, so I wanted an upgrade (as I'd bought several spare batteries). According to my initial research, everything pointed towards the Nitecore D4. At the time of my research, the Nitecore D4 was $60. It has since dropped to $40, making it a great value. Well, the Tenergy is brand new to the Amazon Canada Marketplace. Are the differences worth $60? That'll be a matter of opinion.
Here are the major differences between the Nitecore D4 and the Tenergy TN456 as I see them:
1) Display Parameters - The Nitecore has a basic display, but it shows charge in mAH, voltage, and time spent charging. Similarly, on the Tenergy, you can cycle through the same parameters; however, they're displayed boldly and individually. Regarding the backlight, each company adopted the opposite methodology. Tenergy's screen is unlit unless you press the mode swap, which sparks the backlight, clearly illuminating the display even in the dark. On the Nitecore, the backlight is on by DEFAULT. You have to manually change it into night mode to turn the back-lighting off. Ultimately, I think the Tenergy's display is slightly nicer, particularly because of the individual battery info... but it's very close. WINNER: Very slight edge to Tenergy based on personal preference.
2) Current Range - The Nitecore advertises charging at 750mAH. This is true IF you are charging 1-2 batteries. However, if you charge 3-4, the current drops to 350mAH as a standard. Many Amazon reviewers have corroborated this, so it's not an occasional phenomenon. The Tenergy, on the other hand, can charge at several levels between 300mAH and 1000mAH (whichever you require), and when you charge 3-4, it will NOT drop the charging current. WINNER: Tenergy
3) Test Mode - The Tenergy has the ability to test your battery capacity, fully charging it, draining it, and then charging it to measured, test capacity. The Nitecore D4 does not have this capability. WINNER: Tenergy
4) Production Location - I could not find out where Nitecore chargers were manufactured. Their main website is aloof as to their production location. All I know is that their flashlights company is based out of Singapore, so... I still don't know where their chargers are manufactured. Tenergy is based out of Silicon Valley, California. They built a production plant there in 2009. So if you're looking to keep things local, Tenergy is a good bet. WINNER: Tenergy
5) Price - The Nitecore D4 started at $60. In 2015, it acquired an update, and more recently, it dropped to $40. This makes it a very strong candidate for a budget, no frills charger. The Tenergy is brand new on the Amazon Marketplace. At $60, you're paying for the difference in charging and North American make. WINNER: Depends on what you're looking for
~ Other Stuff ~
Each individual battery display flashes "FULL" when it's finished charging. That's aboot it.
•• Conclusion ••
The Tenergy TN456 is a great charger. If you want a unit that can test battery capacity and has a guaranteed 1000mAH charge capability, go with the Tenergy. Keep in mind, the additional phone charge slot. I suspect the price will lower the longer it's on the marketplace, too. One last point is that the instructions are written in very clear English. This isn't a Chinese re-brand with unintelligible instructions. If you're simply looking for a cheaper, effective charger, cast your gaze to the Nitecore series. The i4 is even cheaper than the D4; it simply lacks the LCD display.
Edited note: This charger does not come standard with a car adapter.
Images in this review
Maya BeWell
Good for environment, good enough for me: The battery health tool: versatile unit of convenient size and ease of use.
Reviewed in Canada on May 22, 2018
Maya BeWell
Reviewed in Canada on May 22, 2018
Rechargeable batteries- contribute towards a smaller climate footprint, yet lose their capacity to hold charge overtime. This unit will ‘clean them up’ ( discharge) and then charge them- increasing their service life. Dual use :pic 4- Battery and phone charger ( 1A usb slot). 4 vs 5 star- as the manual was diff. to understand, (but lots of details, and I am a novice at this.). Charges 4 items, and 4 types of batteries. pic 1 Each battery has its specific display, to monitor its charging progress. display screen is huge- backlit to see at night / low light ( it turns on, and tuns off if no button is pressed)- see video.
MY USE: Need a lot of batteries got this for mouse/keypad, clock, flashlight batteries, ranging high drain (gaming keyboard) to low drain (flashlight). This unit customizes my charging needs (charging /discharging current: how fast the battery is charging), recharges newer or much used battery (battery slow because of inactivity), a discharge mode to erase battery memory, and shows battery energy released, after discharge and not just charged inputted via charge. Uses optimal charge time / as per battery specs. ( does not fast charge-to overheat them).
TIPS
- med sized unit, best for travelling, but multi charger ( charges phone+batteries)
- Needs 2 hands operation to accurately adjust the springs to align battery contacts in bay, see video for inserting batteries correctly. or pic 3
- springs are med tight, good and bad- will not lose tension- but best to fit in the battery with 2 hands. see video part 2
- bring batteries to room temp- before charging ( if stored in fridge) , some say to freeze in ziplock ( no personal experience with this)
Images in this review
Matthew
Great Charger!
Reviewed in Canada on August 1, 2019
Matthew
Reviewed in Canada on August 1, 2019
The only cons this thing has is that it uses a wall wart instead of an internal power supply and that it can only deliver max 1A (1000mA) charging per slot.
Attached is a couple pictures of the charger on Test/Charge mode. The info shown is the actual capacity of the batteries.
Images in this review
