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

The media could not be loaded. 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.

** 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.