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Opus Tester Analyzer Battery Charger, 12V, Black
Package Type: Standard Packaging|Change
Price:$29.96+ Free shipping with Amazon Prime

[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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5150+ comments| 280 people found this helpful. Was this review helpful to you? Report abuse
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.
22 comments| 51 people found this helpful. Was this review helpful to you? Report abuse
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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on February 27, 2016
This tester does not have the most intuitive user interface; sometimes gets "confused" and requires a reboot to set mode and/or parameters. The minimal user manual documentation could be greatly improved. Does seem to test batteries well once test is set-up and initiated. Each cell can be independently set-up and tested or you can set up all for the same test. Has discharge, charge, quick test (measures internal impedance), discharge/test (measures cell capacity), and recondition (multiple charge/discharge cycles) modes. Control over discharge and charge currents (max varies depending on number of cells tested). Measures individual cell voltages. Can be used with just one cell (unlike other testers I've used, which require testing in pairs). Did find that if a cell is completely discharged, the tester won't recognize that it has been inserted and indicates "null" on the display (no cell present). You will have to use an external "dumb" charger to bring the cell voltage up enough for the Opus to recognize it. Kind of an irritating problem for a "smart" charger. Another silly problem; using the included cell adapters for larger batteries renders the quick test useless due to the high resistance of the adapter contacts.
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on November 24, 2016
I've had quite a few battery chargers over the years, almost all of them much more expensive than this one. This is the least finicky of them all. It also has several useful modes in addition to simple charging. The other reviews have covered this so I won't go any further.

One thing I just discovered that I consider worthy of note was I tried charging a battery that had apparently self-discharged so far the charger didn't recognize it. Despite the charger showing nothing in that slot I left it there overnight. To my surprise, the next morning it showed that it had charged that cell. Apparently the post-charge trickle current goes through all the time and that was enough to eventually bring that battery back to life. I've not had opportunity to try this on any other batteries so I have no idea if this is a "feature" or just dumb luck this one time.
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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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on December 20, 2014
This Opus charger is really nice!

I'm a "strobist-style" photographer and flashlight lover, so I have lots of AA and AAA batteries to regularly recharge. It will come as no surprise that I also have several smart chargers. My main workhorse for over 10 years has been a Maha 8-bay C800S. Alas, it recently died. My favorite (until Opus arrived) is the 4-bay LaCrosse BC-700. A good one (oldie-but-goodie) for travel has been the Maha MH-C204F as it comes with a car-charge cable as well as AC. I've got an older model IC-1029-S08 HiTech 10-bay that's very s-l-o-w so does not get used much. And a few others... some a little bit smart, some kinda dumb.

I was looking for a new 8-bay but reading about the Opus (especially NLee the engineer's review... excellent and comprehensive as always!) made me very curious about it, so I bought one. I'm glad I did!

The technical details have been covered well by others, but I'll mention a few special details that impressed me. Lighted display is very useful. The Opus is larger than the LaCrosse, but the extra space between and under the batteries really does keep them cooler. At 200mA charge rate they don't get over room temp. At 400mA there is barely any warmth. Batteries stay cooler than in any other charger I've used, and charging speed is excellent. The buttons and logic make it easy to move through various charging modes and rates and check on the specs of various cells.

I recommend the Opus highly! And even better: compared to the competitors, it's a great value.
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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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on March 8, 2015

This thing total rocks.

MLEE has done a pretty good review, and I have to agree this is a decent unit.

What I like about it is the ability to TEST batteries by charging and discharging them under load, then recharge them.

Now the reason this is SO cool, and SO helpful, is that many NiMH batteries do not get their full potential until they've been discharged and charged a few times.

In my case, I was charging Eneloop 2200s for long term storage. So I was able to run several charge / test cycles to get them ready for a few years in storage...

On another note, this unit was even able to recondition some non-LSD (low self discharge - were well past the 1960s folks! wink) Energizer AAA and AA batteries that the OEM chargers would no longer charge. Surprisingly, they are working great now...

Lastly, this charge will report to you the total number of mA of capacity the batteries end up with. This allows you to know if the batteries are actually doing well, or heading toward the end of their lives.
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on February 3, 2016
Does what it says. I have run most of my existing and new rechargeables through the unit (mostly Eneloops). Does 1-4 at a time; AAs, AAAs, Cs and Ds; and will charge individually and mixes of batteries. I see that it has increased mAh capacity of some of my older cells. Unit cycles them down to about .9 volts, then back up to about 1.45 when finished. (Alkaline one-times can drop down to about 1.2 volts VERY quickly (30-40% of capacity used), while LSDs stay above 1.3 volts for most of their life. Then the Opus will trickle-charge them at 10-20 mAh. I then write the final mAh reading on the battery to keep track of their capacities. (BTW, the Eneloops are the best cells I have tried so far). This Opus received good reviews everywhere I researched. Finally, I chose this Opus as opposed to the Maha & LaCrosse because the Opus charges Cs & Ds. Cheers!
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