Opus BT-C2000 Vs. BT-C700 by AACycler

DEar AACycler refer to your investigation:
http://aacycler.com/post/opus-bt-c2000-vs-opus-bt-c700/


This is a nice job that I appreciated, thank you!


Regarding the BT-C700 there are 2 versions, I have 3pcs of the first version and only one piece of the second version.
What I didn't understand is which version of the BT-C700 was used in its test.


There is a difference in charging poor or cheap batteries, where the second version delivers the maximum current for a longer time (the value of 1000mA) than the first version.


Some time ago I had checked the value of the Minus Delta V, which turned out to be 2mV, as in the image below, but things don't always go so well with cheap batteries:



In any case, the BT-C700 delivers a pulse current of about 1000mA (As confirmed by the HKJ test) even when charging at only 200mA effective the current is formed by short pulses of 1000mA.
The thermal effect on the internal resistance of the batteries (mainly heat) is definitely higher than 200mA of true constant current.

Some pulse chargers work so as to reduce the effective (harmful) heating effect compared to constant current.

Apparently also helps with accuracy when the cell voltage can be more accurately measured during the "pauses" with no current flowing.

john61ct said:

Some pulse chargers work so as to reduce the effective (harmful) heating effect compared to constant current.

Click to expand...

Pulse charging will heat more than constant current charging, when the average current is the same.

john61ct said:

Apparently also helps with accuracy when the cell voltage can be more accurately measured during the "pauses" with no current flowing.

Click to expand...

When measuring voltage with current off, there is much less noise (This saves money on filtering) and connection resistance can be ignored, the disadvantage is that the -dv/dt signal is smaller.

hc900 said:

Regarding the BT-C700 there are 2 versions, I have 3pcs of the first version and only one piece of the second version.
What I didn't understand is which version of the BT-C700 was used in its test.

Click to expand...

When I power on my OPUS BT-C700 charger it shortly shows 2.2. I guess that's the firmware version. HKJ tested the older OPUS BT-C700 v2.1.

hc900 said:

In any case, the BT-C700 delivers a pulse current of about 1000mA (As confirmed by the HKJ test) even when charging at only 200mA effective the current is formed by short pulses of 1000mA.

Click to expand...

Are we talking about the same charger? I don't see 1000mA pulses on HKJ's graphs. Instead I see constant current that gets interrupted once per minute when the charger takes voltage readings with current turned off.

Cheers,
AA Cycler

AA Cycler said:

When I power on my OPUS BT-C700 charger it shortly shows 2.2. I guess that's the firmware version. HKJ tested the older OPUS BT-C700 v2.1.



Are we talking about the same charger? I don't see 1000mA pulses on HKJ's graphs. Instead I see constant current that gets interrupted once per minute when the charger takes voltage readings with current turned off.

Cheers,
AA Cycler

Click to expand...

200mA effective current:




And about 1000mA:



About 70% charge ON and about 30% charge OFF. Less than 1000mA effective costant current.
Note: valid for BT-C700 V2.1

hc900, you are right. The graphs with the 1000mA pulses are right there in the very page I posted myself. My bad. I must have been blind to miss them.

Thanks for correcting me!

Cheers,
AA Cycler

AA Cycler said:

hc900, you are right. The graphs with the 1000mA pulses are right there in the very page I posted myself. My bad. I must have been blind to miss them.

Thanks for correcting me!

Cheers,
AA Cycler

Click to expand...

Here only HKJ is right, who has done a monstrous job, so much so that I myself forget the things I should remember.


Thanks to you AACycler who conducted an investigation complementary to HKJ: your works complement each other.


Of course the results are not what you expected, but at least we understood that things work decently even without using Eneloop or Fujitsu batteries.




For my part I should start to test the -Delta V on each channel of my chargers and at any current value ... I think I will end just before man reaches Mars or Saturn. :laughing:
I should do it just because I know that with my 4 BT-C700s sometimes they overcharge the cheap batteries.



OT:
But other chargers have had much bigger problems:


An investigation on Nitecore i2New with D type battery charged at 1000mA (is a lost feature the 1000mA recharge with the I2New): -Delta V treshold is about at 30mV




Cordially

Hello,
I have the BT-C700.My firmware is 2.1.
What is the difference between 2.1 and 2.2?

Thanks

marcosg said:

Hello,
I have the BT-C700.My firmware is 2.1.
What is the difference between 2.1 and 2.2?

Thanks

Click to expand...

new firmware 2.2

1) with the Display key you can keep the light always on or always off

2) fast charging at 1000mA has now improved with exhausted or cheap batteries. But the power supply hasn't changed, so I think the improvement comes from the firmware