Test/Review of Charger Opus BT-C1000

[size=+3]Charger Opus BT-C1000[/size]





Opus makes a couple of different chargers, this charger here is a 4 channel charger that can charge both LiIon and NiMH batteries and it is possible to select between two currents.



It got this charger in a plain white cardboard box, probably because the real box was not finished yet.



The box contains the charger, and a power supply, with this early version the manual is missing.



The charger has a 12V input that is used with the supplied power supply.



The user interface is a read and a green led for each slots and a long bar, the bar hides two buttons, one in each side.
The red led is on when charging.
The green led shows charge rate after a press on the bar (Fast flashing:1A, slow flashing:0.5A), when the charger is in the CV phase it flashes and when charging is done the light is steady.
Press once on the left or right side of the bar to show the current selected charge rate for the two left/right channels. Press again to change the charge rate.



The slots uses the usual construction and works well. They can handle batteries from 34mm to 74.9 mm long. This is longer than any xx650 batteries one the market, even the extra long ones (Very nice).









The charger can handle 74 mm long batteries, inclusive flat top cells.
The charger is not rated for C and 26xxx batteries but they do fit into it and the current is acceptable.
The current is too high for 10440 cells, except IMR types.



[size=+2]Measurements[/size]

• Red led is on when charging.
• Green led shows charge rate after button press.
• Green led shows CV phase on LiIon.
• First press on button will turn green led on to show charge rate, next press will change charge rate.
• The charger shows error (Flashing red led) with 0 volt batteries.
• With just a little voltage the charger will start charging with selected current.
• Charger will assume LiIon at about 1.8 volt
• The charger will use full current up to 4.2 volt
• When not connected to power it will drain about 0.4mA from a LiIon and 0.04mA from a NiMH battery.
• Charge will restart charging after power loss, or battery insertion.
• When charge is finished the charger will discharge LiIon with 4mA.
• Charger will restart if voltage drops to 4.16 volt.

[size=+1]LiIon charging[/size]




This looks like a nice CC/CV charge with a 50mA termination, this is fine.





The other channels has the same CC/CV curve.



The charge curve is also good at 0.5A, the termination current has been reduced to about 30mA.



This cell do not look very good and reveals that the charge is a simulated CC/CV curve (The problem is a fairly high internal resistance in the battery, this spoils the voltage regulation with a simulate CC/CV curve).
Also note that the final voltage is within allowable tolerances.



With a better cell the curve looks fine.



Surprising enough the charger handles this old cell perfectly.




These two are also handled perfect.



The charger can charge with 1A on all 4 channels, but it do get a bit warm.



It uses about 1700mA from the power supply.



M1: 37,6°C, M2: 40,4°C, M3: 39,3°C, M4: 37,6°C, M5: 42,3°C, M6: 38,9°C, M7: 37,2°C, HS1: 53,7°C

The batteries are not to warm, placing the batteries away from the front may help in that regards.



The charger will start very fast when powered on, it does not wait for current selection, but start at the lowest charge current.



The current can be changed at any time, usual with two presses on the button (One to show the selected current, next to change it). There is no ramp when changing current.



The charger has some small pauses when charging, this is measurement pauses for the simulated CC/CV charge.



[size=+1]NiMH charging[/size]



This is a -dv/dt charging, when finished it switches to a 10mA trickle charge.
The trickle charge is a steady current, not pulses.





The 3 other channels looks the same.



0.5A do also charge and terminate fine.





No surprise with the 3. high capacity cells, they all terminate fine on -dv/dt.



Same with the AAA cell.



For a -dv/dt charger it is very fast to detect a full battery.



No problem charging 4 cells at 1A.



About 0.8A is needed from the power supply.



M1: 31,3°C, M2: 32,6°C, M3: 32,7°C, M4: 32,0°C, M5: 33,8°C, M6: 32,4°C, HS1: 38,7°C

The NiMH cells are not very warm during charging, but they will warm up for a short time during termination (Above picture is not from termination).



The charger will also start very fast with NiMH batteries.



The current can be changed at any time, usual with two presses on the button (One to show the selected current, next to change it). There is no ramp when changing current.



The charger has some small pauses when charging, this is measurement pauses to detect the -dv/dt signal.



[size=+1]LiIon+NiMH charging[/size]



With one NiMH battery and 3 LiIon batteries, the charger has no problem with charging the NiMH.
As usual the thermo sensor is on another battery.



One LiIon and 3 NiMH works just as fine.


Testing the supplied power supply with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.



[size=+2]Conclusion[/size]

Generally the charger does a good job with both LiIon and NiMH batteries and it keeps fairly cool while charging especially NiMH. The user interface works, but I prefer something where I directly can see the charge current, not where I have to evaluate a flash rate.
Indicating when batteries reach the CV phase can be useful if you need the batteries fast and do not need them fully charged.
The BE18650-26 cell is a problem, except for that I will call it a good charger. The best solution is to not use 1A charge current on old cells or only charge protected batteries.

That means the final result is an acceptable rating.



[size=+2]Notes[/size]

The charger was supplied by Opus for review.

Here is an explanation on how I did the above charge curves: How do I test a charger

Thank you for your hard work and this review! This looks like a pretty cool charger.

I wonder why they took away the LCD screen?

RI Chevy said:

I wonder why they took away the LCD screen?

Click to expand...

Probably a way to make a slightly cheaper charger. LCD+LCD driver cost considerable more than a few leds.

RI Chevy said:

I wonder why they took away the LCD screen?

Click to expand...

Yeah, I prefer the one with the screen. But I'm a battery/charger geek like many here. But I guess that's mainly intended for those who want user selectable options. This model might be targeting typical consumers while retaining the sophisticated programming of the original. It would also be somewhat more portable.

Thanks to HKJ for another great review.

Hi HKJ,

What does it mean that you used 2500 and 5000 volts to test the power supply? Are you actually using voltages that high?

magellan said:

What does it mean that you used 2500 and 5000 volts to test the power supply? Are you actually using voltages that high?

Click to expand...

Yes, I am. One wire connected to the two mains plugs, the other connected to the low volt side. This is a safety test that all not earthed mains supplied equipment must be able to withstand. The test voltage depends on what mains voltage the equipment is rated for, with 230VAC the voltage is 3000VAC or 4243VDC. My tester only has a 2500 volt and 5000 volt setting.

It is a good idea to keep the hands away from the equipment when doing this test!

Thanks, very interesting. I didn't know that was a standard test. Is there a specific part of the supply or component that is more vulnerable that this test is aimed at?

I suppose this is to protect users from possible faults or shorts?

magellan said:

Thanks, very interesting. I didn't know that was a standard test. Is there a specific part of the supply or component that is more vulnerable that this test is aimed at?

Click to expand...

Especially when testing usb power supplies I have seen many different problems, the mains ones are:

Not using a proper safety capacitor between mains and low volt side. Some supplies uses a 1000 volt ceramic capacitor that shorts permanently when hit by over voltage (Very bad).

To short distance between mains and low volt side, the worst ones down to 0.5mm where the legal requirement is over 6mm. Some of them I can see when I do a tear down, but using 5000 volt will reveal problems without opening the device.
Here is a photo from a usb charge I tested today (It is a spark in the read circle) and I did only reach 2500 volt:



These safety requirements are because 230VAC (or 120VAC) are not always the nominal voltage, but can have peaks much higher (Each time the fridge stops you may get a peak). Anything with an inductor or transformer can make very high spikes on the mains.

Thanks much for the info. I sorta figured the capacitors and transformers would be especially vulnerable.

I take it this little ceramic capacitor isn't part of the power supply's main filter caps which are usually pretty good size?

magellan said:

I take it this little ceramic capacitor isn't part of the power supply's main filter caps?

Click to expand...

It is part of the noise suppression, but when using a capacitor between mains and low volt side there are some special safety requirements. The capacitors used are called "Y capacitors" (Try google), they are usual blue with a lot of approval marks on them.

Thanks for taking the time to answer my questions. Will Google that.