IMAX B6 Clone with strange behavior on VB1 after calibration.

[Fernando Gewehr]

First I would like to congratulate you guys for this great project. Surely most of you must have lost many nights and worked hard to get here.

I have a clone of IMAX B6. http://www.dx.com/pt/p/2-5-lcd-ac-dc-dual-power-b6ac-80w-rc-balance-charger-discharger-123252#.U3ph3RC84xk

The PCB is attached bellow. Despite being "another" clone, the data pins are equivalent to the original IMAX and not the clone.

I have been reading the other messages, but could not find anything related to my problem. I apologize if this has been asked before.

I'm using version 0.32 IMAX B6 Clone.

Voltage Calibration (normal) was made with 130 ohm 1% resistors in series and adjustable font 25.2V. Measurements were taken with my fluke.

4.2 V adjust on Vb1, Vb2, ..., Vb6.

Icharge and Idischarge was made with a lipo and my fluke.

OK, everything set..., but no, i got misreadings on VB1 balance port when charging my lipo.

I made the calibration again, but now after the calibration i set my power source to 18V. Fluke shows a solid 3V on every resistor, but the charger shows ~3.5V on VB1 and 3V in the other balance ports.

You think is hardware or software related? Or maybe this charger isn't yet covered by your firmware?

thanks and best regards.

Fernando Gewehr

[Paweł Si]

interesting,

could You do some more measurements?

 - go to "options"->"calibrate"->"expert DANGER!"

 - measure the voltage on cell 1 and 2 at 25.2V

 - write down what the charger says on: Vb0pin, Vb1pin, Vb2pin at 25.2V

 - measure the voltage from GND ("data" connector) to the first 3 balance leads leads (Vb0pin, Vb1pin, Vb2pin) at 25.2V

and repeat the procedure at 18V

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[Paweł Si]

another question: did You connect also the chargers main leads to the power supply? You should

[Fernando Gewehr]

About the first question, in the read-me:
"Calibration - Expert (IMAX B6)"
It's written "if the resistance is very low (less than 1k Ohm) STOP THIS PROCEDURE!". Well i have measured and this is my case, i got 0 ohm.

About the second question, i have conected the main leads of the power source.

[Paweł Si]

2014-05-20 2:42 GMT+02:00 Fernando Gewehr <fernan...@gmail.com>:

About the first question, in the read-me:
"Calibration - Expert (IMAX B6)"
It's written "if the resistance is very low (less than 1k Ohm) STOP THIS PROCEDURE!". Well i have measured and this is my case, i got 0 ohm.

Yes, that's right, but

do NOT connect any battery between GND and Vb0pin, 

use you calibration circuit: "130 ohm 1% resistors in series and adjustable font 25.2V"

and only measure the voltage between GND and Vb0pin, ...,

Your charger should be fine.

[Fernando Gewehr]

Sorry for the delay, I could not find time these days.

Here are the measures.

Em segunda-feira, 19 de maio de 2014 18h05min13s UTC-3, cheali-charger escreveu:

interesting,

could You do some more measurements?

 - go to "options"->"calibrate"->"expert DANGER!"

 - measure the voltage on cell 1 and 2 at 25.2V

Cell 1 == 4,184V
Cell 2 == 4,193V

 - write down what the charger says on: Vb0pin, Vb1pin, Vb2pin at 25.2V

Vb0 == 0,212
Vb1 == 4,387
Vb2 == 8,587

 - measure the voltage from GND ("data" connector) to the first 3 balance leads leads (Vb0pin, Vb1pin, Vb2pin) at 25.2V

Here i got a doubt, Vb0pin is the black wire of batery balance port (rightmost pin)? or the next one?
Assuming that Vb0 is the rightmost pin:
Vb0 = 0V
Vb1 = 4,182V
Vb2 = 8,384V
Next pin... 12,571V

and repeat the procedure at 18V

18V:

Cell 1 == 2,985V
Cell 2 == 2,995V

Vb0 == 0,205V
Vb1 == 3,147V
Vb2 == 6,140V

Vb0 = 0V
Vb1 = 2,982V
Vb2 = 5,988V
Next pin... 8,985V

[Paweł Si]

that's strange,

voltage on cell 1,2 is calculated:

Vb1 = Vb1pin - Vb0pin

Vb2 = Vb2pin - Vb1pin

you should see, at 25.2V:

Vb1 = 4.387V - 0.212V = 4.175V

Vb2 = 8.587V - 4.387V = 4.200V

at 18V:

Vb1 = 3.147V - 0.205V = 2.942V ??? (not 3.5V)

Vb2 = 6.140V - 3.147V = 2.993V

I also notice that  your PCB on the upper right corner has an additional chip,

is it a op-amp? (*)

The charger is probably an improved version.

This is what you should do:

1. check if pin 13 from 74HC4051 is somewhere connected (I'm assuming it's not) 

2. check (*)

3. check if pin 14,15 from 74HC4051 go to (*)

If that's the case I will generate a new cheali-charger version for You.

Best Regards,

Paweł

[Paweł Si]

Hi Fernando,

I have added a new version of cheali-charger (I'm assuming 1.,2.,3. is true):

https://github.com/stawel/cheali-charger/tree/master/hex/not_tested/not_ready

I didn't tested it, so please be careful.

You should calibrate the voltage and check if other voltages are displayed correctly.

Go down with the power supply voltage form 25.2V to 10V (or even less).

If it works please send me your eeprom after a full calibration.

Best regards,

Paweł

[Fernando Gewehr]

Hello Paweł,
I will open my charger and map the pins you mention. And i will test the new software.
About the measures. I also found it odd when testing again with 18V. But i remember now that i have reset the eeprom values and i did a new calibration just after my first message. Thing that i didn't in the first place.
Tonight i will post the results.

Best Regards,

Fernando

[Fernando Gewehr]

Hello Paweł,

The software testing show exellent results, from 25,2V to 12V i read near perfect values now...

You are right about the pin 13 of the 4051, it doesn't connect to anything.

And you are right about the CI, is an LM2904.

The pins are connected as the schema.

I save the eeprom file using extreme burner software, please, verify if this works for you.

PS. Idischarge 300 mA value are to high, took a while to put into 300mA, i think holding the inc/dec button is not working as expected on Idischarge.

Best Regards,

Fernando

[Fernando Gewehr]

Hello Paweł,

I've been out of the hobby for awhile. but now coming back ....
I got some batteries for a new project, they have 2200mAh and 3000mAh, both 3S. When I charge the battery of 2200mAh the charger only provides ~1144mA, despite the limit being in 2200mAh. Is that correct? Same happens to the 3000mAh battery. attached are some pictures for you to better understanding.

These batteries are used, but they are still functional. I have read about internal resistance (IR), it's said that above 30mohm battery are dead. my battery show a hight IR on charger, but i think they are still good.
What values of IR are common to see on the other chargers?

[Paweł Si]

2014-08-08 2:08 GMT+02:00 Fernando Gewehr <fernan...@gmail.com>:

Hello Paweł,

I've been out of the hobby for awhile. but now coming back ....
I got some batteries for a new project, they have 2200mAh and 3000mAh, both 3S. When I charge the battery of 2200mAh the charger only provides ~1144mA, despite the limit being in 2200mAh. Is that correct? Same happens to the 3000mAh battery. attached are some pictures for you to better understanding.

hm...  no, they should charge at 2.2A, 

can you try to calibrate the charger again and check if it helped?

(please report me on that)

These batteries are used, but they are still functional. I have read about internal resistance (IR), it's said that above 30mohm battery are dead.

 

no that's not true, the IR depends on the capacity of the battery (200mAh should in theory have a 10x larger IR compare to 2000mAh)

and the quality of the battery (less IR, better manufacturer) and other factors (for example the temperature).
but it is true that the IR increases over time and it is a good indicator that the battery is in a bad shape.

(but you would need to know the batteries IR  when it was new)

 

my battery show a hight IR on charger, but i think they are still good.

 

Another thing is that the value shown by the charger is not very accurate and shouldn't be taken to seriously.

but the simplest rule is that a battery is dead if it doesn't work anymore :)

(I know, that's obvious, but true) 
   

What values of IR are common to see on the other chargers?

Unfortunately, I do not know.

[Fernando Gewehr]

Em sexta-feira, 8 de agosto de 2014 20h21min40s UTC-3, cheali-charger escreveu:

2014-08-08 2:08 GMT+02:00 Fernando Gewehr <fernan...@gmail.com>:

Hello Paweł,

I've been out of the hobby for awhile. but now coming back ....
I got some batteries for a new project, they have 2200mAh and 3000mAh, both 3S. When I charge the battery of 2200mAh the charger only provides ~1144mA, despite the limit being in 2200mAh. Is that correct? Same happens to the 3000mAh battery. attached are some pictures for you to better understanding.

hm...  no, they should charge at 2.2A, 

can you try to calibrate the charger again and check if it helped?

(please report me on that)

I just flashed my charger with 0.33 and done a full calibration. And the charger still can`t reach more than ~1145 mA. Despite this the charger is working very well.

[Paweł Si]

2014-08-09 2:05 GMT+02:00 Fernando Gewehr <fernan...@gmail.com>:

Em sexta-feira, 8 de agosto de 2014 20h21min40s UTC-3, cheali-charger escreveu:

2014-08-08 2:08 GMT+02:00 Fernando Gewehr <fernan...@gmail.com>:

Hello Paweł,

I've been out of the hobby for awhile. but now coming back ....
I got some batteries for a new project, they have 2200mAh and 3000mAh, both 3S. When I charge the battery of 2200mAh the charger only provides ~1144mA, despite the limit being in 2200mAh. Is that correct? Same happens to the 3000mAh battery. attached are some pictures for you to better understanding.

hm...  no, they should charge at 2.2A, 

can you try to calibrate the charger again and check if it helped?

(please report me on that)

I just flashed my charger with 0.33 and done a full calibration. And the charger still can`t reach more than ~1145 mA. Despite this the charger is working very well.

Ok, I found the bug, please download the fixed version from:

https://github.com/stawel/cheali-charger/tree/master/hex/not_tested

unfortunately I recently lost all my partitions and I have a new system now, with a new avr-gcc (version  4.8.2)
I newer tested cheali-charger with the new compiler so be careful.

Best Regards,

Paweł

 

[Fernando Gewehr]

Em sexta-feira, 8 de agosto de 2014 21h32min43s UTC-3, cheali-charger escreveu:

2014-08-09 2:05 GMT+02:00 Fernando Gewehr <fernan...@gmail.com>:

Em sexta-feira, 8 de agosto de 2014 20h21min40s UTC-3, cheali-charger escreveu:

2014-08-08 2:08 GMT+02:00 Fernando Gewehr <fernan...@gmail.com>:

Hello Paweł,

I've been out of the hobby for awhile. but now coming back ....
I got some batteries for a new project, they have 2200mAh and 3000mAh, both 3S. When I charge the battery of 2200mAh the charger only provides ~1144mA, despite the limit being in 2200mAh. Is that correct? Same happens to the 3000mAh battery. attached are some pictures for you to better understanding.

hm...  no, they should charge at 2.2A, 

can you try to calibrate the charger again and check if it helped?

(please report me on that)

I just flashed my charger with 0.33 and done a full calibration. And the charger still can`t reach more than ~1145 mA. Despite this the charger is working very well.

Ok, I found the bug, please download the fixed version from:

https://github.com/stawel/cheali-charger/tree/master/hex/not_tested

What can i say... You are the man...

Working great now.

Thank you very much Paweł.