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Discussion Starter #101
That's great news, thanks for sharing. So it looks like these packs can be reset when they have gotten off in the weeds.

It is a bit strange how far out the cell balance was from each other., but it is quite difficult to match cells by discharge.
 

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The PIC 16f1786 need an ICD3 or PICkit3 to be programmed / read.
At office, we only have the ICD2.
I wanted to try to read the PIC or its EEprom


PicKit3 connected to the PIC connector :
The program is protected, but i succeeded to read the eeprom
First read on a 2.6 Ah battery:

0 FF FF FF FF FF FF FF FF
8 FF FF FF FF 0C 0 FF FF
10 FF FF FF FF FF FF FF FF
18 FF FF FF FF F3 FF FF FF
20 36 1 A3 0 7 FF 1A 0F
28 FF FF FF FF FF FF FF FF
30 C9 FE 5C F8 FF FF E5 F0
38 FF FF FF FF FF FF FF FF
40 FF FF FF FF FF FF FF FF
48 FF FF FF FF 0C 0 FF FF
50 FF FF FF FF FF FF FF FF
58 FF FF FF FF F3 FF FF FF
60 FF FF FF FF FF FF FF FF
68 FF FF FF FF FF FF FF FF
70 FF FF FF FF FF FF FF FF
78 FF FF FF FF FF FF FF FF
80 FF FF FF FF FF FF FF FF
88 FF FF FF FF FF FF FF FF
90 FF FF FF FF FF FF FF FF
98 FF FF FF FF FF FF FF FF
A0 FF FF FF FF FF FF FF FF
A8 FF FF FF FF FF FF FF FF
B0 FF FF FF FF FF FF FF FF
B8 FF FF FF FF FF FF FF FF
C0 FF FF FF FF FF FF FF FF
C8 FF FF FF FF FF FF FF FF
D0 FF FF FF FF FF FF FF FF
D8 FF FF FF FF FF FF FF FF
E0 6E 5 41 0D 7B 4 F0 0A
E8 0 1 20 FF FF FF FF FF
F0 FF FF FF FF FF FF FF FF
F8 FF FF FF FF FF FF FF FF

Hex 1A = 26 in decimal, maybe the battery capacity !
 

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Discussion Starter #103
i suppose there is no way to read out the firmware when it is locked--what a pain. Seems like somebody would have figured out a way to read the code while it is running in single-step mode with an emulator tool?

i looked at the eeprom data in another format, but nothing jumps out.

Code:
2.6 A-Hr PIC eeprom																		

00  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  0C  00  FF  FF
10  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  F3  FF  FF  FF
20  36  01  A3  00  07  FF  1A  0F   FF  FF  FF  FF  FF  FF  FF  FF
30  C9  FE  5C  F8  FF  FF  E5  F0   FF  FF  FF  FF  FF  FF  FF  FF

40  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  0C  00  FF  FF
50  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  F3  FF  FF  FF
60  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
70  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF

80  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
90  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
A0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
B0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF

C0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
D0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
E0  6E  05  41  0D  7B  04  F0  0A   00  01  20  FF  FF  FF  FF  FF
F0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
 

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The image is better but not bright enough.
Mine was taken with my Samsung S9
A faulty battery for $ 10:

Nothing is happening.
All cells below 0.1 V. Pull up to 3.6V with a power supply, but always nothing.
No light when push on the capacity button, and flashing on the charger.

The U1 marking is 3710LN 090.4G 1850B
The U3 marking is Q822J or O822J Z34 06 18511A
 

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Discussion Starter #105 (Edited)
U3 looks like an NXP microcontroller, if it's in the 8051 family there is possibilities. [LPC82x has IAP and ISP programming with on-chip code up in the high memory; that's how we found the code to read the LPC used in the TCCH/Elcon chargers]

i noticed there is a reset junction.

Are the cells holding at 3.6V after p/s charging?

i suppose the FETs are OFF?

Big electrolytic C6 looks damaged.

Is the GND strap on there with a good solder joint near CL1- ? It looks sketchy to me. Also the solder at the strap near CL6 looks cut?

if i had it i would remove all the big solder globs at the CLs and Power and trace out the power and ground connections.

That looks identical to Kith's 3.0 A-Hr pack, same part number and revision, Q. Looks fairly new, March 2019 date code.
 

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....
i noticed there is a reset junction.
I tried it, no effect

Are the cells holding at 3.6V after p/s charging?
Yes, no variation after 1 day.

i suppose the FETs are OFF?
Yes, Off

Big electrolytic C6 looks damaged.

Is the GND strap on there with a good solder joint near CL1- ? It looks sketchy to me. Also the solder at the strap near CL6 looks cut?

if i had it i would remove all the big solder globs at the CLs and Power and trace out the power and ground connections.
It can be a photo effect, I did not notice any problem of component or welding

What capacity is that pack? Looks fairly new, March 2019 date code.
It's the same posted by Kith
On the mine, the date code on the label was cleared
 

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i suppose there is no way to read out the firmware when it is locked--what a pain. Seems like somebody would have figured out a way to read the code while it is running in single-step mode with an emulator tool?

i looked at the eeprom data in another format, but nothing jumps out.

Code:
2.6 A-Hr PIC eeprom																		

00  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  0C  00  FF  FF
10  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  F3  FF  FF  FF
20  36  01  A3  00  07  FF  1A  0F   FF  FF  FF  FF  FF  FF  FF  FF
30  C9  FE  5C  F8  FF  FF  E5  F0   FF  FF  FF  FF  FF  FF  FF  FF

40  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  0C  00  FF  FF
50  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  F3  FF  FF  FF
60  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
70  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF

80  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
90  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
A0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
B0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF

C0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
D0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
E0  6E  05  41  0D  7B  04  F0  0A   00  01  20  FF  FF  FF  FF  FF
F0  FF  FF  FF  FF  FF  FF  FF  FF   FF  FF  FF  FF  FF  FF  FF  FF
2.6 Ah


5.0 Ah
 

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Discussion Starter #108
i had noticed on the 2.6 that the values in column x0C, when added together

0C + F3 = FF,

and the same for the 5.0,

10 + EF = FF.

Wonder if it is counting down how many times it has been charged? More puzzles.
 

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I have several functional batteries but which lack capacity.
The battery works well on the mower but after 10/15 min , it stops and restarts every minute.
This symptom is confirmed on the 2.6 ah dated 2011/2012.
When you replace the cells, the problem goes away.
I tested each cells of the defective battery, i didn't noted any failure, just a loose of 20% of the capacity ( 1100 mA vs 1300 mA )

At the begining , the problem was only on the 2.6 Ah.
Now, I have a 2016 5Ah with this problem.
PCB desoldered, 18 V battery pack separated to be tested on my power supply and electronic load.
I manualy charge the 18V pack at 21 V 2Ah ( 4.2V by cell ).
And i discharge at 5Ah with a cut-off at 14V ( 2.8V by cell ).
Periodicaly, i checked the individual cell voltage. The cells had a good balancing.


Both batteries pack have the same capacity and i don't see any problem
I don't know why when you replace the cells, the problem disappears.
 

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i had noticed on the 2.6 that the values in column x0C, when added together

0C + F3 = FF,

and the same for the 5.0,

10 + EF = FF.

Wonder if it is counting down how many times it has been charged? More puzzles.
A 2nd 2.6 Ah battery eeprom PIC
 

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Discussion Starter #111 (Edited)
I have several functional batteries but which lack capacity.
The battery works well on the mower but after 10/15 min , it stops and restarts every minute.
This symptom is confirmed on the 2.6 ah dated 2011/2012.
When you replace the cells, the problem goes away.
I tested each cells of the defective battery, i didn't noted any failure, just a loose of 20% of the capacity ( 1100 mA vs 1300 mA )

At the begining , the problem was only on the 2.6 Ah.
Now, I have a 2016 5Ah with this problem.
PCB desoldered, 18 V battery pack separated to be tested on my power supply and electronic load.
I manualy charge the 18V pack at 21 V 2Ah ( 4.2V by cell ).
And i discharge at 5Ah with a cut-off at 14V ( 2.8V by cell ).
Periodicaly, i checked the individual cell voltage. The cells had a good balancing.
...
Both batteries pack have the same capacity and i don't see any problem
I don't know why when you replace the cells, the problem disappears.
That is quite a puzzle; i would have thought it was the mower shutting off using the T2 possibly due to over-temperature, or the pack shutting off for over-temperature. But when the problem disappears just due to cell change, it somewhat excludes the over-temp fault.

Possible theory: Maybe there is a low-voltage cutoff level, and the weaker cells let the pack drop too low under high load. When the load was removed the cell voltage bounced back up above the threshold, but then tripped again when under high load.

The 5AHr pack appears to still have good capacity when tested at 1C, but i suspect that the mower has a higher current draw and will bring cells down faster to hit the mower's LV shutoff point, maybe..?

i have a couple of "bad" packs that will charge to 4 bars, then run the mower or chainsaw for a period and cut off. The scale shows 1 bar; then i let it set for a bit and shows 3 bars, and starts back up to run for another period. Similar to your experience? i call them "bad" packs because they were discarded for recycling due to not working; i opened and charged the low cell(s) individually, and then they work and charge as normal except those low cells are likely weak and causing the LV cutoff.

Another idea: these cells have vents and internal protection devices with a thermal cutoff. A spec sheet that i found indicated no explosion and no fire requirement. Maybe that device is turning ON and disables the pack for a brief time, then resets itself?
 

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The 18V packs has been tested with a 8A discharge current.
The curves are the sames. No problem detected.
I will try to solder a 2,6 Ah BMS on this 5Ah battery.
Test to follow....
 

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Oric,
Keep us updated on that AliExpress battery.
Do you have a link the the one you purchased?
Can you tell what the cell manufacturer and model are used?
 

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Oric,
Keep us updated on that AliExpress battery.
Do you have a link the the one you purchased?
Can you tell what the cell manufacturer and model are used?
The cells marking is THISS 18650HR20R
Probably a 2000 mA, with 2 in parallel, the nominal capacity is 4000mA and not 6000mA as notified on the label.
Two discharge tests on my electronic load gave 3500 mA
The weigth of this battery is 1.2 Kg vs 1.5 Kg for an original 5Ah.
The battery accept to charge on the original charger.
But the capacity indicator is false. The 3 first led rise very quickly. In 1 minute, the 3rd led is flashing.




Unable to post a link on the forum.
But write "Powtree Ryobi 40V LED 6000mAhOP4026A" on google.
 

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Discussion Starter #116
thanks for sharing your test data, that is very interesting that it works with the OEM chargger.

There is a "chain links" icon in the menu bar, hopefully that is a way to post a link?
 

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Discussion Starter #118 (Edited)
That seems like a great price, i hope it works well and has a long life. i might have to buy one just to trace it out, especially with no shipping cost.

Did you identify the microcontroller chip? Is it a PIC 16F1933, i couldn't make out the markings clearly.

i see that is a Rev 5 board and does not have the reference designators for the components such as shown on Rev 6.
 

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All

Here are few updates.

1. Even though the charger would work on a battery with voltages posted ( see #100), it errored out towards the end. I believe this is how batteries get into this defective stage. For some reason the BCM could not charge all cell banks to the same voltage. I had to discharge some cells and get them to the same(almost) voltage. After that I was able to charge the battery all the way without any errors.

2. After a full charge, when I press the capacity check button, only 3 lights light up. I am not sure what is the reason for this. If I try to charge it again, it would not charge the battery. I can use the battery on my tools without any issues.
 

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Discussion Starter #120
Maybe the 4th LED is burned out or that circuit has an issue. Next time you have it open can check it with a DMM.

The cell balancing capability is very limited with the OZ8940 chip, like .008 Amps of discharge current depending upon the value of the RF1 resistors. It may be that the code just gives up if the voltage difference exceeds some stored limit, another reason for all the "dead" packs out there for sale on ebay.

Good work to get them matched close enough for it to recover. It takes a good DMM that can read down to the mV level generally for messing with cell voltages. 0.1 V is a huge difference in cell world.
 
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