Test/Review of Charger Opus BT-C700

8 posts / 0 new
Last post
HKJ
HKJ's picture
Offline
Last seen: 8 hours 11 min ago
Joined: 05/24/2011 - 12:23
Posts: 7433
Location: Copenhagen, Denmark
Test/Review of Charger Opus BT-C700
Charger Opus BT-C700

DSC_9599

DSC_9601 DSC_9600

This is a compact 4 channel analyzing charger from Opus.

DSC_0267 DSC_0268
DSC_0269

I got the charger in a cardboard box.

DSC_9598

The box contains the charger, a power supply and a manual.

DSC_9605

The charger has a barrel connector for 12V power input.

DSC_9602

As all analyzing charger it has a display and a couple of buttons.

DSC_9738

When powered on the charger briefly shows the version number of the software.

DSC_9739

Selftest during powerup shows all the text on the display.

DSC_9740

When working the display looks like this, the DISPLAY button can be used to select what to show (v/h/mA/mAh).
The MODE button is used to select mode for one or for all slots, it is also possible to change mode later on.
The CURRENT button will step between the possible currents.

DSC_9603 DSC_9604
DSC_9607

The charger uses a AA/AAA two level slot. Notice the metal strips touching the side of the battery, this is probably connected to a temperature sensor.

supportedBatteryTypes

supportedBatterySizes DSC_9609 DSC_9608



Measurements
  • When not powered it will discharge the battery with 0.4mA
  • Charge will restart charging after power loss, or battery insertion.


Charge

The charge mode can select between 200, 300, 400, 500, 700 and 1000, default is 400mA. The 1000mA is only available in slot #1 and #4 and only when slot #2 and #3 is empty.

Opus%20BT-C700%20charge%20700mA%20(eneloop)%20%231

The charger reduces current when the battery is nearly finished, this keeps the heat down, but makes it more difficult to terminate correctly. This charger is smart enough to terminate correctly even at the lower current.
Display shows 2027mAh in 3:20

Opus%20BT-C700%20charge%20700mA%20(eneloop)%20%232
Opus%20BT-C700%20charge%20700mA%20(eneloop)%20%233
Opus%20BT-C700%20charge%20700mA%20(eneloop)%20%234

The same with the 3 other slots, all have nice terminations.
Display shows 2049mAh, 2020mA, 2030mA in 3:28, 3:18, 3:23

Opus%20BT-C700%20charge%20200mA%20(eneloop)%20%231

Even at 200mA current the charger do a nice termination.
Display shows 1849mAh in 9:27

Opus%20BT-C700%20charge%20400mA%20(eneloop)%20%231

With 400mA the current is high enough to see the increased temperature when the cell is full.
Display shows 2052mAh in 5:53

Opus%20BT-C700%20charge%201000mA%20(eneloop)%20%231

The charger is rated to do 1A, but it is at the limit.
Display shows 2078mAh in 2:29

Opus%20BT-C700%20charge%201000mA%20full%20(eneloop)%20%231

The charger needs some time to reconize a full cell, but it is smart enough to do it at low current.
Display shows 190mAh in 0:22

Opus%20BT-C700%20charge%201000mA%20(eneloopXX)%20%231

This XX is also fully charged.
Display shows 2076mAh in 2:52

Opus%20BT-C700%20charge%201000mA%20(eneloopPro)%20%231

Same with the Pro.
Display shows 2623mAh in 3:07

Opus%20BT-C700%20charge%201000mA%20(powerex)%20%231

For some reason the 1A charge current is slightly lower here, but the cell is perfectly charged.
Display shows 2553mAh in 3:15

Opus%20BT-C700%20charge%20500mA%20(eneloopAAA)%20%231

The AAA is no surprise, also perfectly charged.
Display shows 790mAh in 2:00

Opus%20BT-C700%20charge%20700mA%20(4xeneloop)

With four cells the maximum charge current is 700mA and it is handled fine (Remember my temperature sensor is not mounted on the same cell as the V/A sensors).
Display shows 1944mAh, 2091mAh, 2032mAh, 2091mAh in 3:06, 3:21, 3:15, 3:20

Opus%20BT-C700%20charge%20700mA%2012V%20(4xeneloop)

The charger uses below 1A from 12V.

Temp2106

M1: 43,6°C, M2: 47,4°C, M3: 48,3°C, M4: 44,4°C, M5: 51,5°C, M6: 32,6°C, HS1: 58,9°C

With the compact size the temperature is a bit high at full charge current.

Temp2105

M1: 42,1°C, M2: 46,1°C, M3: 46,2°C, M4: 42,5°C, M5: 50,6°C, HS1: 69,2°C

Startup

The charger is a bit slow to start, because it is waiting some seconds for user input.

Charge200mA

Charge current is regulated with pwm.

Charge1A

Here I have selected maximum charge current, but due to my sense equipment (0.1ohm resistor in series with battery) the charge cannot reach full current.

TrickleCharge

Trickle charge is done with a current spikes each 30 second.

TrickleChargePulse

The spike is 0.0003 second long.



Discharge

The discharge mode can select between 100, 200, 300, 400 and 500mA, default is 300mA

Opus%20BT-C700%20discharge%20500mA%20(eneloop)%20%231

The discharge is to somewhere between 0.8 and 0.9 volt.
Display shows 1855mAh in 3:44

Opus%20BT-C700%20discharge%20100mA%20(eneloop)%20%231

A 100mA discharge takes a lot of time.
Display shows 1931mAh in 19:23

Opus%20BT-C700%20discharge%20500mA%20(4xeneloop)

Discharging four cells at once will heat the charger.
Display shows 1895mAH, 1980mAh, 1977mAh, 1980mAh in 3:39, 3:59, 3:50. 3:59

Temp2115

M1: 38,7°C, M2: 41,5°C, M3: 42,1°C, M4: 39,2°C, M5: 50,5°C, M6: 34,1°C, HS1: 54,2°C
Discharge do also generate some heat, but not as much as charging.

Discharge100mA

Discharge is also done with pwm, above curve is lowest current.

Discharge500mA

Highest discharge current.



Discharge Refresh

This function will cycle the cell a couple of times, it finish with a charged cell.

Opus%20BT-C700%20dischargeRefresh%20500mA%20(eneloop)%20%231

Display shows 1904mAh in 2:30



Charge Test

This function will charge the battery, discharge the battery and then charge it again. The display will show the discharge capacity and time.

Opus%20BT-C700%20chargeTest%201000mA%20(eneloop)%20%231

Looks like two nice charge curves with the discharge between.
Display shows 1948mAh in 2:28



Quick test

This function measures the internal resistance of the battery, this is an indication of how well the battery performs (Lower value is better).

ri1
ri2

First line shows the reading when I just put the battery in the charger.
The second line shows the reading when connected to my test equipment, but without extra resistance.
+10, +40 and +100 means I have added that much resistance (Tolerance is only a few mOhm), the result is supposed to show these values.
All tests are done with the same battery.

The charger gets wrong result frequently when I am using my test rig. I suspect that my test rig is affecting the charger.

ri1x
ri2x

Replacing the wrong result with the value from an adjacent column makes the result look very good.

QuickTest

The charger load the battery a bit before doing the actual measurement.



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



Conclusion

This is a compact analyzing charger and this means it will run a bit on the warm side when using full current. The charge algorithm is a bit special with the lower charge current when the battery is nearly full, but it works well and do keep the final temperature lower.

All functions works as expected, the user interface is easy to use and it was not early or late on a single termination, this makes it a good NiMH charger.



Notes

The charger was supplied by gearbest for a review.
I have tested two copies of this charger, the first one was faulty and would not terminate when using lower charge currents!

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

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Edited by: sb56637 on 06/25/2015 - 14:21
ChibiM
ChibiM's picture
Online
Last seen: 13 min 27 sec ago
Joined: 05/09/2011 - 10:25
Posts: 6714
Location: Holland

Thanks me HKJ.

How soon did you realize the first copy wouldn't terminate?

Could be possible more copies of this charger have that problem. And most non-geeks have no idea about this, and will trust the charger to do its work properly.

HKJ
HKJ's picture
Offline
Last seen: 8 hours 11 min ago
Joined: 05/24/2011 - 12:23
Posts: 7433
Location: Copenhagen, Denmark

ChibiM wrote:
How soon did you realize the first copy wouldn't terminate?

When doing the first charge. I did run a few more test to confirm the problem.

ChibiM wrote:
Could be possible more copies of this charger have that problem. And most non-geeks have no idea about this, and will trust the charger to do its work properly.

There might be more with the problem, but as long as the display do not report that it is finished it is fairly easy to spot.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

ChibiM
ChibiM's picture
Online
Last seen: 13 min 27 sec ago
Joined: 05/09/2011 - 10:25
Posts: 6714
Location: Holland

Ok. Think it's good for a little warning in case people buy one for inexperienced users. 

Thanks again for the test!!!!

xephon
xephon's picture
Offline
Last seen: 1 month 1 week ago
Joined: 04/30/2013 - 07:19
Posts: 80
Location: /ˈsɪŋəpɔr/

Is the C700 the latest OPUS charger for purely NiMH charging? I see also a C2000, C2400 BM100 and BM200 model all from Opus doing about the same thing. :~

I’m looking for a BC700 replacement and don’t need Li-ion features.

hammerJoe
Offline
Last seen: 1 year 5 months ago
Joined: 02/12/2015 - 19:56
Posts: 150
Location: Canada

Yes the 700 is the latest charger from Opus.
it only does Nimh.

Babou
Offline
Last seen: 1 year 1 month ago
Joined: 07/26/2020 - 13:09
Posts: 18
Location: Belgium

I ordered it and received it in 15 days to replace my old Sony, after testing it
I have only one thing to say, it is the best of the best Ni-mh chargers Star

I have only one desire to buy a lot of them Cool Thumbs Up

High Voltage, warning, warning, warning !

xephon
xephon's picture
Offline
Last seen: 1 month 1 week ago
Joined: 04/30/2013 - 07:19
Posts: 80
Location: /ˈsɪŋəpɔr/

Babou wrote:
I ordered it and received it in 15 days to replace my old Sony, after testing it
I have only one thing to say, it is the best of the best Ni-mh chargers Star

I have only one desire to buy a lot of them Cool Thumbs Up


Mine’s 5 years and still going strong. Thumbs Up Looks like there hasn’t been newer models from Opus since.