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216 of 220 people found the following review helpful
[Full Disclosure]:
Several months ago, a distributor sent me (unsolicited) two pre-production units of BT-C2000 Battery Charger Tester Analyzer for my feedback. I was reluctant to write this review since it may give people the impression that I'm now accepting free samples for 'honest' reviews. However, since I already spent time playing with this charger, I might as well share my findings for the benefit of others. Just keep in mind that the following observations are based on pre-production models.
[End Disclosure]

I have purchased several advanced battery charger/tester/analyzer in the past 7-8 years, including the La Crosse BC-900,BC-700,BC-500 ,BC1000,Maha MH-C9000,AccuPower IQ-328 and BM200. Unfortunately, they all have either design limitations or features that I miss. The BM200, in particular, looked most promising as it combines the best features between BC1000 and MH-C9000. But it failed to become my ultimate 'go-to' charger due to poor thermal management.

The BT-C2000 Battery Charger Tester Analyzer can be viewed as the 'version 2.0' of BM200. With new firmware and circuit board design, it claims to have solved the thermal problem, and added some useful refinements to the user interface. Here are my findings on this charger:

From the outside, the BT-C2000 looks exactly the same as the BM200. That means it is sized right in-between BC1000 and MH-C9000. The way to distinguish BT-C2000 from BM200 is to check the firmware version. During power up, the leftmost window shows a "2.0" briefly.

[Power Supply]
The BT-C2000 charger unit is powered by a 12V supply from AC wall unit, similar to that for BM200 and MH-C9000. They all share the same 2.1/5.5mm barrel plug, so I can freely interchange the adapters. The BC1000, on the other hand, requires a 3V supply to operate, so it cannot operate directly from 12V car battery through a cigarette lighter adapter. All AC adapters are designed for 100-240V AC input.

The LCD display is identical to that of the BM200. It has four independent columns, showing the status of all four cells at once. This is much better than the MH-C9000's single-column display, which can only display one parameter of one cell at any one time. The display has a backlight which automatically times out after 10 seconds of inactivity. This is an improvement over both BC1000 (no backlight) and MH-C9000 (backlight stays on).

The default charging current has been increased from 200mA (in BM200 and BC1000) to 400mA. This is a most welcomed change, since the new default current works well for both AA and AAA cells. In contrast, the BC1000's default current of 200mA is too low for AA, while the MH-C9000's default of 1000mA is too high for AAA.

Naturally, you can press the CURRENT button to change all charging currents in 200mA steps (400 -> 600 -> 800 -> 1000 -> 200) before charging starts. When charging only two cells in slot#1 and 4, the charging current can be increased to 1200 or 1400mA. You can also select any one cell using the SLOT button, and adjust its current independently. Unlike the BC1000, you are free to choose current higher than that used by previous cells.

The BT-C2000 shares similar features found in BC1000 and MH-C9000. The operation is controlled by pressing the MODE button:
- REFRESH (called CYCLE in MH-C9000)
- TEST (called ANALYZE in MH-C9000)

In addition, the BT-C2000 added a "QUICK TEST" function, which measures the internal resistance of each cell. This is useful to screen for old cells that have developed high internal resistance. All my good-quality AA NiMH cells (Sanyo eneloop) have resistance around 50 mOhm or less. Some of my old Energizer cells have resistances around hundreds of mOhm. Those can still be used in light-drain appliances such as wireless mice. (The MH-C9000 does an impedance check whenever a cell is inserted, and refuses to charge it if the resistance is too high.)

The BC1000 has a known bug: if the terminal voltage of a depleted cell drops below 0.5V, the charger cannot detect it and the display says `null'. The BT-C2000 has mostly resolved this problem. In my testing, it is able to detect a depleted cell with just 0.1V across. However, in case the cell is over-discharged to 0V or polarity reversal (negative voltage), the display will still say `null'.

The over-heating problem found in BM200 seems to be mostly resolved in BT-C2000. The charger does not suffer from 'thermal hiccup' even when charging 4 cells at 1000mA. However, cells still get rather warm to the touch near the end of charging phase. The MH-C9000, on the other hand, keeps the cells lukewarm when charging at the same current. This is mostly due to its larger case and ventilation space between cells.

So far, I like everything I saw on the BT-C2000 - except for the following problems:
1. The DISCHARGE function is quite useless. It discharges a cell down to 0.9V, and then recharges it back to full automatically. The `mAh' number you see in the end is for the final Charging phase, not for the initial discharge. I rather have the charger stops after the Discharge phase, and preserve the 'mAh' number. This is how the MH-C9000 implements its DISCHARGE function.
[Update: a reader confirmed that DISCHARGE function in the production model works correctly now]

2. During DISCHARGE/REFRESH operation, the 'mAh' reading from previous Discharge phase is not preserved. Instead, it shows the accumulated charge during the present Charge phase, which is useless information. This makes it impossible for me to measure the remaining charge in a cell, which is vital for my long-term battery self-discharge rate measurement. (The BC1000 preserves the 'mAh' reading from the previous Discharge phase, so I have a few hours to record the data)

3. I tried to charge two C cells through the C/D-to-AA adapters in slots #1 and 4. Although I can select the highest current of '1400mA', the actual current I observed varies all over the place between 900mA and 1200mA. Apparently, the extra resistance introduced by the adapter makes it difficult for the charger to regulate at higher current.

I must stress again that my observations are based on pre-production models. It is possible that the final model may have addressed those issues.

With the exception of the issues mentioned above, I consider the BT-C2000 to be the best advanced charger/analyzer I have found. Once those issues are resolved (hopefully through firmware update), it could become my ultimate 'go-to' charger for battery testing as well as daily charging. Maybe by then, I can finally get rid of the other half a dozen advanced chargers that I own. In the meantime, I will hang on to my BC1000 and MH-C9000.

[Update on May 14, 2014]
There seems to be a lot of confusions about the DISCHARGE function. For the final production model, DISCHARGE is supposed to stop right after cell voltage has dropped to 0.9V. But apparently, some people received older models which recharge automatically after Discharge is done (same as my pre-production model). Both models display firmware version 2.0 during power up.

I strongly suggest people should look for the latest BT-C2000 Battery Charger Tester Analyzer with firmware v2.1. It made several improvements that I like. See my review on it for details.
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41 of 41 people found the following review helpful
on February 3, 2014
I bought the Opus BT-C2000 few days ago. NLee the engineer’s review above is very complete (as always from NLee :) ), and accurate from what I have seen so far so I’ll just add my observations.

First impression, this Opus BT-C2000 is a very complete charger/analyzer and is easy to use. I got interested by this charger because it advertised the capability to charge/analyze cells up to 20,000mAh and has C/D cells adapters included in the box. I use high capacity C/D cells, so this looked like the right charger to get the job done. I’ve seen review of C/D cells adapters for other charger which do not fit/clip well in chargers, but the Opus ones are tight are work well. It does handle the C/D cell like any other cells, except for resistance checks (the adapters add resistance leading to wrong readings…)

The charger has thermal sensors for both the batteries and the unit itself. Info from the user manual, (I don’t have the tools to verify…), if it detects a temperature of 60deg on a cell, it will pause the on-going operation to let the cell cool down. If it detects a temperature of 70deg in the unit, it will also pause the operation to allow cooling down. This is very nice to prevent damaging the cells or the unit.

From an analysis I’ve read, the charge is gentle and seems to give a very nice and delicate finish, adjusting the charge rate toward the end. This good technical analysis can be read on candlepowerforums dot com. I would recommend googling it if interested in more technical details (simple google search “Opus BT-C2000 review”).

Once the charge is completed, it goes to a 10 to 15mA rate (seems to be depending of the type of cell being charged), just to maintain its level (I would still not leave the cells there for long periods...).

The charge function is set to 400mAh as default, but can be increased to 1000mAh if the 4 slots are used, or 1400mAh if slots 1 and 4 are used for C/D cells with the adapters. This is good for high capacity C/D cells, but still a little long to get a full charge. Being a high capacity D cell user, I would like a bit more, like 2000mAh. But 1400mAh still gets the job done. One observation, when charging my high capacity D cells, it seems to be hovering between 1100-1250mAh, not 1400mAh constant. But still does a good job at handling the charge smoothly. Another observation, I charged Imedion C cells at 800mAh and at this rate, the current was very stable on 800 until going into “finishing mode”.

The charge-test function will analyze the capacity of a battery by charging, discharging and re-charging the cell. The mAh values after the discharge function are kept on the display, allowing keeping note even after the cycle is completed.

The quick check function measure the internal resistance of a cell in milliohms. One good point, it can measure alkaline batteries as well. I actually had a bunch of alkalines on the shelf and I check them all for voltage & internal resistance, I found out many were too low V or too high ohms to be used.

Overall, a very good, useful and complete unit. My only few complains would be: I wish the slots were C and D cell sized instead of using an adapter, it would allow charging and testing 4 D cell (or 4 C cells) at the same time instead of only 2, and I wish the charge rate would go to 2000mAh to address high capacity cells a bit faster. There might also be some work to be done on the algorithms for high current charge as it does not seem stable. But these are minor “nice to have” and it’s not enough to lower my rating. The overall unit is very good… I give a fair 5 stars to the product.
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28 of 28 people found the following review helpful
VINE VOICEon February 1, 2014
After my La Cross BC-700 gave up the ghost after many hard years of use that included dropping it far more times than I can count I went in search of a replacement. Used almost exclusively on AA eneloops for photography speedlite use with the rare occasional AAA usage. On a typical week I recharge a set of 16 AA's two/three times a week so it gets considerably more use than the typical household.

The controls are easy to use, and if you've used a "smart charger" before you'll quickly figure out after reading the instructions how to operate the unit. It gives a bit more time after battery insertion to set mode and charge rate than the La Cross which is nice. Even under high charge rates of 1000 the batteries get warm but not hot. I've recharged hundreds of batteries and "refreshed" many in it as well and the unit has not faltered, become hot, or failed on a single battery. I really like it, it's easy to use, the display is easy to see and it's become a workhorse.

Now about that observation. I purchased new eneloops and immediately "refreshed" them as I typically do and noticed that the #1 and #4 slots showed the exact same charge level of 2044 after the process was complete. Didn't really make note of it but as I began using the unit I began to notice a pattern that the #1 and #4 slots almost always showed the same charge regardless of which eneloop battery was put in it when in refresh mode. Now I imagine it's possible that Nikons speedlites quality control is so good it always drains batteries exactly the same and that Sanyo's QC is also so well controlled that each battery also holds the exact same amount but it's difficult for me to believe that I can always randomly get those batteries in the #1 and #4 slot. ( someone way smarter than me could figure out the probability of that happening) It's not always the same total number, but #1 and #4 are the same as each other 95% of the time or within a single number, say 2023 and 2024 the other 5%. Slots #2 and #3 work normally with normal results say, 2114 in one and 2065 in another. It doesn't seem to effect the performance of the batteries in the speedlites and I don't have the equipment to see if they are indeed affected in anyway, but something odd is going on in there!
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16 of 16 people found the following review helpful
on January 2, 2014
I have the BC-700, BC-900, and Vanson. This is a nice full feature charger. The discharge function does not recharge after drain is a nice feature. I wish they have put a little more effort and make a 4 slot C/D adapter instead of each independent slot adapter which limit it to only 2 channels. Only 1 negative complaint: I get bad reading from my C/D batteries with Quicktest function using the provided C/D adapters. It is probably due to poor contacts or faulty firmware. I cannot identify the problem. About one in 8 or 9 tries, I get proper reading. I have about 8-D Acculoop (NiMH), 6-C Tenery Centura (NiMH), 4-D (Ni-CAD). All reading was +500 mohms to +900 mOhms. Once in while, i get proper reading of 80mOhms or 40 mOhms. It does not affect the charging though. Proper reading of voltage when charging. Quick test on AA/AAA read properly though: 52mOhms to 80mOhms.
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11 of 11 people found the following review helpful
on February 27, 2014
The Opus has 5 modes to select from
Charge - test
Quick - test

"Charge:" -- this most most frequently used. It charges at the mA you select (200mA, 400mA etc to 1400mA) until the battery is full.

"Discharge:" -- this is really useful. I put a non rechargeable battery in. It starts to discharge and shows me the voltage across the battery. Batteries are meant to supply power at 1.5Volts. When the power drops below 1 volt then your battery has very little power left. That battery might have enough power for a wall clock but otherwise isn't worth keeping. So I'm going through my box of old batteries (awaiting recycling), to find ones which still have power. If 4 batteries were in a electric toy, say that 3 were empty but one was full. The toy stopped working and so i put all 4 in the box for recycling. I'm finding that about 33% still have good power.

"Discharge - refresh" -- in order to recover an old rechargeable battery.
Sometimes a battery might be rated for 2500mAh ie the total amount of power that it can hold. However lets say that you've been charging it with a quick charger (which can supply 1000mA to the battery and fully charge it in 2.5 hours). The problem with quick charging after a few times is that it shortens the life of the battery and it also reduces the total amount of power that it can store. (e.g. from 2500mAh to 1000mAh so it is now able to store less than half).
This mode will discharge and fully re-charge the battery 3 times at a low current which will help restore the battery back closer to its original capacity (e.g. 2500mAh)
That sounds great, doesn't it. However if you have a D cell battery with a stated capacity of 3000mAh and you choose the lowest charge setting (200mA to charge, it will default to discharge of 400mA). It takes 15hours to charge, 7.5 hours to discharge. This mode does this 3 times for a total of 2 days 20 hours. You could use a higher current of course, but the whole point of this mode is to recover the old battery by using the lowest charge possible. The OPUS can only hold 2 C,D batteries at a time. So the amount of time needed is huge.

Otherwise. Ive had fun with this. I've put in brand new duracell ultra batteries and discharge them to zero just to see what total power (mAh) they contain at a 200mA power drain. I've also tested several brands of recyclable batteries.
My conclusion is that if your using a low drain product (e.g clock, radio, rarely used flashlamp) then use cheap non-branded disposables. If your using a high drain product (e.g. anything with moving parts, camera flashlight etc) then use Sanyo Eneloop 3rd generation.
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7 of 7 people found the following review helpful
on February 27, 2014
As others have mentioned, this is a great little charger. I have tons of rechargeable batteries, and they seem to reach a point where they don't hold a charge anymore.

With this little charger, I was able to run the refresh cycle on many of the batteries and bring them back to life. Others, since I could tell how much charge they hold, I could tell when they were ready to retire.

Finally, I tore apart one of the battery packs for my drill. It would no longer accept a charge. Once I got the batteries free, I used the adapter, along with 3 pennies, to test out each battery individually. To my surprise, they were all still good. They just needed to be refreshed. I put the pack back together and the battery pack now holds a charge just like it is supposed to. That alone made this purchase worthwhile!
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6 of 6 people found the following review helpful
on January 29, 2014
This Opus charger comes with a 4 page manual - in a tiny typeface. A reformatted version of the manual (in larger type) is available at manualslib dot com - search for BT-C2000. Let me try real links...

You can download the manual there in pdf form. (The downloaded pdf will display better than the online viewer version and its is a quick download - only 118KB. FYI, I used finereader.abbyyonline dot com [...] to OCR the manual. It did a phenomenal job.)

Quick summary of Working Modes:
CHARGE ....................... Charge. Once FULL, a small maintenance charge is applied.
DISCHARGE .................. Discharge. When completed "0 mA" is displayed. Press DISPLAY to view discharged mAH capacity.
DISCHARGE - REFRESH ... Cycle: (Discharge, Charge) repeated 3 times. Refreshes older batteries to maximum capacity. Takes many hours.
CHARGE - TEST .............. Cycle: (Charge, Discharge, Charge).
.................................... After completion, the tested discharge capacity is displayed in mAh alternating with "FULL".
QUICK TEST .................. Measures battery internal resistance in milliohms +/- 10%. (Unreliable for C and D cells).

The firmware revision of the battery charger is displayed when you power it up. Mine is 2.0. The box said it was "with 2nd generation firmware and hardware design".

I received this charger just a few days ago (1/23/14) and have only used it a few times. Seems terrific so far. Minor point - I would prefer a Start button so I could take my time reading the display instead of having it auto start after a few seconds. But I guess that makes it easy to do the default mode charge - just pop in batteries and it will do its thing. It would be nice to be able to recall last few results.
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5 of 5 people found the following review helpful
on March 1, 2014
Read a thorough review for this unit and purchased as a result. Very happy w/ it so far. I've been testing, analyzing and refreshing batts for a month, noting the different states of my batts. It's nice to actually know what batteries suck in my collection and what batteries do NOT suck. I was surprised to know that all my Energizer rechargeable batteries meet/exceed their rating... and these are fairly old batteries. I remember buying them, looking for "Made in Japan". I remember in the 80's when "Made in Japan" was not a good thing. :) I have some Duracell batts that are aggressively rated 2650 and they all barely get 2500. Anyway, you will not be disappointed w/ this unit.
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5 of 5 people found the following review helpful
on December 16, 2013
Only a few cycles on my eneloop batteries but easy to program and charges well. I look forward to someone smart like Nlee the Engineer reviewing this charger. Good job.
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4 of 4 people found the following review helpful
on October 12, 2014
I chose this one over the more popular La Crosse based on NLee's reviews. There was a steep learning curve as this is my first advance battery charger. I've owned many "dumb" charger but made the leap to get the Opus after realizing I may be frying my batteries if I keep on using those other chargers. I've read most of NLee's reviews and advices and recommend you do the same. He clearly explains all the nuisances of using the Opus and recommended getting the Version 2.1. Don't buy it through Amazon; they'll send you the ver. 2.0. If you use the C/D adapter it'll hog 2 of the 4 slots. Too bad they don't have a slot for recharging a 9V. That would've been sweet. Overall, highly recommended and I'll never go back to using those stupid chargers again.
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