BT-C2400 Battery Charger Analyzer Tester for AA AAA NiMH NiCd Rechargeable Batteries

** Received September 28, 2015 from Amazon Fulfillment with 2.2 firmware. ** This charger is awesome. It operates more similarly to LaCrosse chargers than the Maha C9000. I have two rechargeable battery intensive hobbies... one is small scale RC Car racing, and the other is photography. I'm constantly charging batteries for one of the two things and as of receiving this one I now own three smart chargers: This one, the Maha C9000, and the Maha C801D. The C801D is a very basic smart charger in comparison and I primarily use it when I need to charge several batteries at once rather than when I want to try to condition and restore a cell so this will mainly be a review in comparison to the C9000. The tl;dr version is, both the Maha C9000 and this Opus BT-C2400 have their strong points and for people that have a need to charge a lot of batteries, I can recommend both for different situations. Get this one if you'll ever be using older batteries as it has a better chance of restoring them. Get the Maha C9000 if you don't use old batteries and have the need to charge cells quicker. ----- The main point I really like about that BT-C2400 charger is that it wont give up on your old batteries that have seen better days. The Maha C9000 does a check when you insert a battery and if it detects too much resistance, it displays "HIGH" and refuses to charge a cell. The BT-C2400 however will attempt to charge the cell to try to restore it (it states in the manual that it will probably charge at a reduced rate to what you select if it detects really high resistance). I was able to restore some power to some old cells that had sat around since 2010. Though the resistance is too high for them to be used for RC racing, they can be used for slower drain items like remotes / controllers / tablet pens. The main point for the Maha C9000 is the ability to charge on all 4 slots at up to 2000 mAh where you're limited to half of that with the Opus (70% of it if you're only charging two batteries on the outer slots). If you need to charge something faster and still want the monitoring functions of a smart charger, the C9000 is the better option. I also like the break in mode of the C9000 for a fresh pack of batteries. You can use the refresh function similarly with the Opus, but even though you have to push more buttons on the Maha I like the break in interface more for it. If you're going to be working with older cells and want to try to restore them to get some use out of them, I'd go for this one over the C9000. The cost is lower and it will service older batteries without a problem where the Maha C9000 might refuse them. If you'll be working with newer batteries mostly and value the higher charge rate, the Maha C9000 is still a tried and tested smart charger and works really well. The Opus BT-3400 is another option, but it does the same thing as this one except it supports other types of batteries. It's really only worth the extra money if you think you'll be using lithium rechargeables. My hobbies only involve NiMH so it wasn't worth the extra $20 to step up. The final alternative is the LaCrosse chargers. I used to own their BC-700 but it just died on me at random so I don't have the best impression of longevity for LaCrosse chargers. Currently, the BC-700 is overpriced for what it does. The Opus BT-C2400 does everything the BC-700 does and more... in fact it's more comparable to the higher end BC-1000 in charging speed while still winning on features and price. To it's credit though, the BC-1000 does come with a case, two sets of batteries, and adapters so that offsets the price difference. At this point, I don't think I could seriously recommend any of the LaCrosse BC-700 at all. The BT-C2400 is simply better and costs less to boot. The BC-1000 should only be an option if you need the adapters to C or D, or if you really really need the smaller footprint of the LaCrosse charger (you don't). So I can really only recommend the Opus or the Maha right now. If you have the money, both have their positive points and I'd get one of each. For everyone else though, unless the faster charging speed is really necessary for you, this is probably the most well rounded smart charger on the market. It's also refreshing to see that they are always updating hardware and firmware so I think they are likely to stand behind their product longer.

Please note that this review was written by me, an actual person. If it seems a bit "too clean", it is because it has been run through Chat GPT simply for improving the style and grammar. After researching smart battery chargers, I initially leaned toward the much hyped Powerex (Maha) MH-C9000Pro. However, after comparing features and price, I ultimately chose the Opus BT-C2400, and I’m glad I did. It performs well and costs less than the Maha. What I Like * Comprehensive Functions: It offers all the essential features of a smart charger/analyzer—Charge, Discharge, Test Internal Resistance, and Discharge/Refresh. * Detailed Display: Shows voltage, capacity (mAh), charging current (mA), and cycle duration. * Thoughtful Design: The battery slots are well-spaced, which helps prevent overheating. * Built-in Safety: Includes a temperature sensor to avoid overheating during operation. * Simultaneous Slot Monitoring: You can view data for all four slots at once. In contrast, the Maha MH-C9000Pro cycles through each slot and stat, which would drive me crazy. * Great Value: Offers excellent functionality at a lower price point. What Could Be Better * Display Behavior: Once a battery is fully charged, the screen only shows "Full" in most modes. I wish it would alternate between "Full" and the selected stat (e.g., mAh, voltage, duration), as it does briefly in Charge/Test mode. You can press "Display" to view other stats, but they flash too quickly to capture or read easily. * LCD Quality: The screen is functional but a bit dated. It has limited viewing angles and reminds me of old digital watches where you had to tilt your wrist just right to read the display. * Inconsistent Resistance Readings: The internal resistance feature is a nice addition, but the readings vary widely and should be taken as rough estimates. Still, it’s a feature the Maha lacks entirely. * Lack of Charge/Discharge Rate Guidance: The manual doesn’t specify recommended charge or discharge rates for AA/AAA batteries during refresh cycles. I had to consult the Maha manual for guidance. Charge/Discharge Rates According to my research, it is recommended that charge mA rates should be no less than 30% of the battery's rated mAh capacity. For example, a 900mAh AAA battery should be charged at no less than 270mA (900 x 0.3 = 270). The reason is that, although low charging rate is generally good for the battery, it may prevent the charger from cutting off when charging is done, therefore potentially overcharging, overheating, and damaging the battery. Final Thoughts The Opus BT-C2400 is a solid smart charger with a robust feature set. It delivers excellent value and functionality. If you're looking for a capable charger without breaking the bank, this one is worth considering.

I use rechargeable batteries often with photography, and when I do a shoot (paid or not) I need to count on my power being rock solid. Batteries have a finite lifespan, and their performance degrades over time.NiCads develop memory, and using an "unmatched" or poor performing battery with a group of good batteries not only damages your good batteries, it reduces your overall performance to that of the weakest battery in the group. I own several of these units, and not only do they let me group my batteries by performance and capacity, they charge my batteries in the best way to keep them lasting a long time. I could write a book on proper charging techniques, but I'll let you do that research elsewhere. The quick hint - use a lower charge current if you want your batteries to last a long time, and don't run a full discharge/test on your batteries all the time because your are effectively consuming recharge cycles from your battery when you do so. Regardless of your charger choice - be sure to use a "smart" charger if you plan to keep your batteries around for a while. Here's my review" Pros: 1. 4 independent charge bays. This means that each battery is charged independently according to its characteristics. Charging 2 batteries together can overcharge a good battery while an older battery struggles to get the correct voltage and current to charge it. 2. Adjustable current levels. If you need a battery quickly, you can bump the current, if you have time to charge slower, you can increase your battery life with a reduced charge current. 3. Ability to measure true mAh of each battery. This is great when you want to match your batteries. I match mine by physical age and measured mAh. I have batteries that still perform well and should have been retired years ago. 4. NiMH or NiCd? - no problem. This charger does them all. Older NiCd's can in many cases be "refreshed" by repeated charge/discharge cycles. I've done it with this charger. 5. Cost - I bought my first unit at $50, as I write this $30 is the going rate. Cons: 1. The manual is pretty poor, but still gets the point across. 2. Calculated mAh rates are not consistent between units. I have 2 units, and whenever I buy a new set of batteries I run a full charge/discharge test to insure that none of my batteries are back, and to match groups of batteries together. Between each unit, I consistently see a reported difference of aprox 15-30 mAh. between units. Is this is big deal? - NO, just remember that your measurements aren't exact, but they are WAY better than using a "non" smart charger. 3. making selections and reading total current is sometimes quick. When you plug in a battery, or several batteries, you can select what option to perform and also at what current. At some point in time, this option gets locked in to prevent you from changing the "smart charge" cycle. Most of the time, I'm quick enough choosing what I want, occasionally I need to reset a battery to allow me to change a setting. In a nutshell, I absolutely recommend these units for your charging needs. Thanks for reading. I hope this helps

My children all have leap pads and I've been recharging their batteries a simple charger that can charge two sets of batteries in parallel. However, after about a year of this I've amassed over 2 dozen AA batteries that are in constant rotation and I could tell that something was going wrong when the batteries weren't lasting very long or not working at all after being charged. Using a voltmeter didn't help since all of the batteries tested as good after being charged. After a little research I decided to ditch my old charger and get one that charges each battery individually and provides some diagnostics for determining when a battery is no longer useful. This charger has good reviews for quality and all of the same features as many of the competitors. After it arrived I started using it to test all of my batteries using the charge test mode. I like this mode it will charge and deplete the battery measuring the total power (mAh) of the battery. The mAh of the battery is printed on the side so i could separate batteries that still held their full charge from the ones that didn't. With the batteries that didn't hold their full charge I tried running the refresh mode on them. I can't say this did anything to improve how much power they could hold and using the quick test mode to determine their internal resistance showed that most had high resistance with maybe a couple that still had lower resistance and might still be useful. Overall I'm very happy with the basic charge and charge test modes. I'm fairly certain the refresh mode is worthless and the quick test mode although useful doesn't provide any guidelines as to what sort of resistance values are normal, marginal, or bad so I had to research this online. The interface is simple and intuitive to use. For the common case of charging the battery or doing the quick test it is adequate. However when running the charge test and refresh modes the ability to clearly display which cycle of each mode its in is a big short coming. In just the charge test mode I can let it slide since you can tell whether its in the first charge, discharge, or second charge cycle by scrolling through the information and at the end of the most important information (the measured mAh) is available. However in the refresh mode where there are multiple charge/discharge cycles it isn't possible to tell which cycle its on and only the information for the latest cycle is displayed so once its done refreshing the battery the only way to know whether there was an improvement is to constantly monitor the charge and write down the measurements for each cycle as it goes through them, I just don't have time for this. One last thought, for the quick test mode I had also hoped that in addition to internal resistance it would provide a voltage reading for the battery under load as well as an estimate for the amount of mAh left in the battery. A general subjective good/bad indicator would also be great so that I don't have to play tech support when teaching the wife how to use it.

I have a bigger charger that does both NiMH and LIon batteries, but with certain NiMH batteries, the internal resistance, when they're older, is enough to trick the charger into thinking its a LIon battery. That results in the charger trying to charge the battery up over 3 volts, overheating the battery as a result. I think this has ruined a couple of my batteries, so I needed a charger that was more single purpose and this charger works perfectly for that. I have an older malfunctioning La Crosse BC-1000 charger that worked really similar to this Opus charger, so am pretty familiar with the charging and refresh modes, but this Opus charger also has a discharge and quick test mode. The instructions don't say exactly why you'd use the discharge function, but that it will take a battery down to .9v (for some reason.) I put one battery I'm trying to resuscitate on the discharge cycle and it took the battery down to .98v, but this morning the battery was back to 1.19, so I'm not sure exactly what the purpose of the discharge cycle is. The battery has already been through 2 refresh cycles on this charger, but it has failed to fix the battery (which discharges really quickly), so I thought maybe this discharge mode would help, but no luck so far. But for batteries that are in better condition, the refresh cycle works as described, displaying the mAH reading at the end, helping you rate your batteries, which is how I found the bad battery above. For those who are curious there is a quick test mode that will display the internal resistance of batteries. I tried it, it gave a number, but I couldn't make much out of it. I suppose if I wanted to research it, I could find out what the internal resistance ought to be, but I'm not sure what I'd do with that info. Overall, I'm really pleased with this Opus charger because it is so similar to my La Crosse charger, is NiMH only and performs well. The only negative I've encountered is that when the battery charging function is done and you see the voltage, then you hit the display button to cycle through the other measurements, it cycles back to voltage within a couple of seconds. So if you have 4 batteries in there, you don't have time to read and absorb the info before it reverts. It doesn't do this in all the modes however, like the discharge mode for instance, so I'm still learning about this. Maybe there's a way around it. If you want a non-LIon charger so your older NiMH batteries won't get over-charged, I would highly recommend this reasonably priced charger.

Although I know how to treat rechargeable batteries, for years, we kept having trouble with them keeping the ability to charge. I don't know for sure if the problem was the chargers or my husband, but either way, we just couldn't make them work. After a few years of wasting money on alkalines and not being kind to the environment, I decided to try again. I researched the heck out of rechargeable batteries and chargers. I confirmed that I'd previously taken care of them correctly, then learned what makes some batteries and chargers better than others. I narrowed it down, then read a ton of reviews. This is the charger I chose. It's been a year since then, and I've been so happy with it! It has all the functions I wanted, it charges the types that I wanted, and it treats each battery separately. It's very clear about when a battery is fully charged. It's super easy to use. I attempted to refresh any NiMH batteries I still had lying around, and while most of them were too far gone, it did help me squeeze a little more life out of a few. If you've had difficulty with rechargeable batteries in the past, it might be worth reading up on their care a bit, but you don't need to look any further for a fantastic charger! The only reasons I can think of to go with something else are if you need to charge different types of batteries, or if it's important to you to be able to charge more than 4 batteries at once. A good smart charger can save you a lot of money, but as a bonus, this charger is very affordable. There may be other chargers out there that are as good as this one, but I'd be shocked if any are better in any objective sense. If you decide this particular one isn't for you, I highly recommend putting in the effort to make sure that the one you get is high quality, because so many appear to be good, but will require more effort from you and still shorten the life of your batteries in the long term.

Congratulations! You can finally stop looking for an AA/AAA Battery Charger. This Opus BT-C2400 charger redefines the term ‘Smart’ charger. Others make claims and either fall short, or fall way short. I’m a techy geek at heart and so when my recent smart charger died, I was off on a journey. I really liked the last charger and was thinking to just simply by another. I then went to the internet and found that they no longer make it, and, the failure I had seen with that design had a common problem (overheating). I then invested about 2 weeks of ‘free nights’ reading, and reading… about all the features of modern chargers. Let me share some very important results of that time and batteries. First, let’s talk about what we are charging. ‘The’ batteries to buy are Eneloop brand which are a premium brand of the low self-discharge type. These batteries hold their charge much longer than traditional NiMH batteries. I use them in remote controls, calculators, and all those other devices that need to hold a charge for more than a few months. One thing though, these great batteries do not like heat. If you treat Eneloop batteries correctly, they can see as many as 2100 charges. So if you get the right charger and batteries, this is a great low cost investment and also a very kind thing for the earth (stop buying those alkaline batteries that go into the trash). I have two young children that commonly forget to turn things off, so being able to put the batteries back on the charger is very welcome. Sadly, if you research enough about most of the chargers out there, they have what is called ‘trickle charge’. After the batteries are charged most of the way, then they are pulsed with a light amount of current to keep them topped off with power. That sounds good, right? Well… sort of. Most of these chargers charge far too high of a current (around 100mA or more). If you leave the batteries in the charger by accident for a few days, you can already be damaging your Eneloops. OK, so best to have no trickle charge or low trickle charge (less than 20mA). The Opus BT-C2400 charges most batteries I have around 7-14mA. This is very very low… a great compromise between topping them off and keeping them full all while not overheating and killing your batteries. While I would suggest you do remove them after charging, there should be no harm if left in the charger for a bunch of days. Next, it is essential to have a good display to see what is going on with your batteries. Many chargers have pretty icons just showing a battery slowing filling up or overly simple green/red light. This tells you almost nothing. Ideally, you’ll know the voltage, the current, the capacity of the batteries and to see all that information for each charging slot. This is again another area where chargers fall short. Here the Opus BT-C2400 does a fine job.. (see pictures of this various screens in action) with information at your fingertips. Many chargers do an OK job with fresh batteries and yet most also do not do well with older batteries. As the batteries get older, their internal resistance increases and their capacity decreases. Many charges will just blink or say ‘null’ and not even attempt to charge older batteries. The blinking can get pretty darn frustrating when you are left wondering ‘now what’. No matter what you do, most of the chargers just won’t even try charging. There are tricks you’ll read about tricking the charger to charge the battery with using a paper clip to jumper the output of a good battery with an older battery. Just Google “null” and paperclip and you’ll see what I mean. But who wants to spend this money and do sketchy things with paperclips… doesn’t sound too safe or good to me. Can’t chargers just be smarter? Well this is probably the most important feature of the Opus BT-C2400. I’m an engineer and we talk about algorithms, these fancy mathematical formulas that make all the math inside these chargers work. Important to know, if you buy the BT-C2000 model, you might get the less optimized firmware. If you buy the BT-C2400, you’ll get the latest firmware/algorithms. The Opus BT-C2400 is monitoring the specific properties of these batteries and adjusts the current to accommodate each batteries health. See video that shows this charger set at 1000mA and yet it sees two older batteries (marked #1 and #2) charging at lower current instead of the dreaded "Null". This allows charging of less than optimal batteries of which all my other chargers won't charge. Also, it keeps battery heat much lower. Simply put, it charges batteries other chargers won’t. This was the primary decision maker for me! If a charger is full of great functions and display but can’t charge batteries... then the rest wouldn’t matter. Speaking of features – I insisted to have Modes to not only charge the batteries, but, also give you an idea of the overall condition of them (diagnostic modes). We don’t want to fill our earth with all these batteries that were thought to be bad due to poor battery chargers. The C2400 can measure the capacity (Charge Test) and internal resistance (Charge Quick Test) and these values can tell you when it’s time to finally recycle the batteries. Even better, there is a specific mode called Discharge Refresh. The charger will cycle a few times charging and discharging in an effort to bring life back to aging batteries. I highly suggest you occasionally use this feature even for ‘good’ fresh batteries, to extend their life. It is always best to deplete a battery before charging and such modes as this will do that and more. My old charger was compact, I thought that was so nice. When narrowing down the search to the last few chargers, I thought I was going to miss how nice and compact since most were significantly larger. Many of the modern chargers charge a huge variety of batteries both NiMH, LiPo, Lithium Ion, NiCd, etc. To accomplish this, there are these spring loaded trays for the batteries. I already have an excellent one like that. It hooks to a computer, can output results in Excel, etc. It has far too many features that I’ll ever use and most of all, getting batteries in it is not fun. It ends up being this balancing act holding batteries just right and letting these sliders pinch the batteries holding them up in the air. Often the battery’s weight is such that the battery can fall out. I expect that most of you will be charging AA/AAA NiMH batteries and if so, this is the Opus BT-C2400 is perfect. If you absolutely needed to have a charger for mixed types such as NiMH, NiCd, Lithium Ion and sizes beyond AA/AAA, then there is the big brother charger the Opus BT-C3100. However, since I use AA/AAA NiMH, I was happy to skip the C3100 and go straight to the C2400. That charger has no sliders and instead dedicated slots that you can effortlessly load AA/AAA batteries into. Also, I learned that I now LOVE the larger charger. I had become accustomed to having to sneak batteries out of the old charger and not pop out the others that were still charging. The old compact charger that I thought I loved, well… I don’t miss it. The larger Opus BT-C2400 allows me to remove a battery in the middle with little effort. It’s a dream. This charger handles all the batteries up to 1000mA. However, a nice added bonus, if you use the outer only two slots, you can actually charge up to 1400mA. It pays to read the instructions! So if you are in a hurry and only need to charge 2 batteries, you can sneak a little extra power into the batteries to speed up charging. This brings up something that I could not research online but had to test myself. Battery temperature with higher current settings. On my last charger, the batteries got hot… sometimes even scary hot. This Opus charger, on any setting so far, the batteries don’t get even close to hot. Batteries being a little warm is very normal for all chargers. With the Opus, the batteries are nearly room temperature most of the time. As said before, this means the batteries will live much longer (many years). I was not given a unit to review, was not paid, nothing. I just fell in love with this charger so much and was so happy that I felt compelled to share this experience. I hope this review will save some folks the many hours of research and nearly 100 chargers I looked at. BTW, I also bought a second charger because I loved it so much. I suggest any of you who are looking for an AA/AAA NiMH charger look no further. Buy some Eneloops and this charger and save the planet of the alkalines eating up our landfills.

By far the best battery charger out there for the price. This thing charges AA & AAA quick and efficiently without overcharging. It shuts off charging when the battery is full. The refresh feature is extremely valuable and effective. For instance, sometimes rechargeable batteries (even Eneleoop) won't charge to their full capacity straight out of the box. You can run the refresh mode on this charger and get the full capacity at no hassle.