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Inside the ARGUS Ni-Mh battery - X-Ray image

Posted: Sat Apr 23, 2016 9:04 pm
by Fraser
I have a collection of ARGUS 1 and 2 batteries including the ARGUS 2 Green ended Ni-Mh rechargeable batteries.

I would like to rebuild the worn out Ni-Mh batteries but wanted to see what 'lives' inside before attempting disassembly.

I was expecting similar to the Alkaline cells battery packs but I was wrong. The Ni-Mh cells are shrink wrapped so there are no individual internal cell holders. The Alkaline battery pack has a small resistor connected between the battery positive terminal and the battery state monitoring pin.

Looking at the X-Ray of the Ni-Mh battery, it is clear that there is a PCB running the length of the battery on one side. The PCB contains at least one IC and I believe it to be a 'gas gauge' circuit, commonly found in rechargeable battery equipment. Sadly I have no knowledge of the exact circuit used or the schematic of the PCB.

The X-Ray will be uploaded shortly as it is currently too large a file size for this forum. I will include an X-Ray of the Alkaline cell battery pack for reference (no cells fitted)

Fraser

Re: Inside the ARGUS Ni-Mh battery - X-Ray image

Posted: Sat Apr 23, 2016 9:20 pm
by Fraser
OK I have compressed the X-Ray images. Hopefully they have not lost too much detail

Fraser

Re: Inside the ARGUS Ni-Mh battery - X-Ray image

Posted: Sun Apr 24, 2016 1:24 pm
by forum_admin
It is a gas gauge circuit using a BQ2010. This was used again on Argus4 (see thread viewtopic.php?f=8&t=20 which includes the BQ2010 software).

The series resistor on the 'AA' pack to the 3rd pin forms a resistor divider with a resistor to ground in the camera so that the 'AA' pack discharging gives the same voltage as the gas gauge direct output presented on the 3rd pin. That way the camera does not need to 'know' which pack is there to give the right battery bar display. The charger also has a bar graph display driven from the 3rd pin.

The difficulty when fault finding is in working out what the BQ2010 is up to without access to the internal registers.

Note that, despite posts on some other forums :
The 3rd pin is not a pack thermistor for the charger. That is wired in the charger above the pack.
The 3rd pin is not the gas gauge 'DQ'
The 3rd pin does not set the charge rate or identify the pack
The 3rd pin does not identify the pack

Re: Inside the ARGUS Ni-Mh battery - X-Ray image

Posted: Fri Apr 29, 2016 4:20 pm
by Fraser
Excellent information.

Many thanks

Fraser