DB6i battery replacement?

[truglo]

I have been having issues with my Dahua DB6i doorbell cam rebooting whenever the chime button is pressed. I have it installed correctly with a chime kit, and it has worked for a while. Since the rebooting with chime issues have started, I replaced the 16VAC-30VA transformer with a 24VAC-40VA transformer, but the problem continues. So I decided to pull apart the camera and noticed the lipo battery inside is bulging and likely bad. I believe this is the cause of the issue, and the battery needs to be replaced. Has anyone done this successfully before?

The battery model on the label reads "1s1p 652023P", and it's a 1 cell 200mah lipo, with a 3-wire management circuit (red/black/white wires). The pack measures 19x23x~6mm (the 6mm dimension is what I figure it was before bulging). I can't seem to find a 3-wire pack to replace it online.

Being an avid and somewhat advanced drone enthusiast over the years, I am comfy with replacing the pack with whatever fits, and soldering wires in small spaces etc. I am tempted to just get another small lipo that fits, but I can't seem to find one with a 3-wire BMS circuit. Also AFAIK the white wire could be used for many things, though usually it's a thermistor (but those can come in different flavors as well). I'm aware that many devices will still work fine even if the extra BMS wire is missing, but I don't want to risk damaging my precious dahua doorbell (being in the US replacement may not be trivial). Despite having decent soldering skills and tools, I'm not so sure I could swap the BMS from the stock pack onto a new lipo without damaging the new lipo though. So I figured I should chime in here before hacking at it. Any help/advice is appreciated.

TIA, Kev

[edit: I figure finding the right pack is going to be harder than just hacking a bit. I looked at the lipo and can see that removing the stock BMS and installing it on a new lipo won't be that difficult once I remove the polyamide tape that holds it on there. I have new polyamide tape to rewrap the BMS after doing this. A new 1s170mah arrives tomorrow, and a 1s200 arrives later this week, which I'll store charge and keep as a backup. Wish me luck, lol!]

 

[Jim_OS]

FYI: Since the Dahua DB61i should be identical in construction to the Amcrest AD410, you can find various information online about how users have replaced the battery in their AD410 Doorbell. Unfortunately, it's a known problem that the battery becomes defective and swollen after a few years. This will probably happen to my identical Imou DB61i soon as well.


The photo of the swollen battery comes from there: Amcrest AD410 Doorbell

Just one discussion on the topic:

https://amcrest.com/forum/amcrest-smart-home-f32/ad410-chime-kit-replacement-t16622-s20.html

 

[truglo]

Amazon didn't have anything for the AD410 that I could find. However my repair attempt went well using the $9 pack I ordered with Amazon prime. Here is what the DB6i looks like inside with the swollen pack. It's seems identical to the AD410 at first glance.



Both BMS boards had "weld pads" soldered on to them, and the lipo tabs were welded to those. So I cut the tabs near the weld pads, and used my soldering iron to remove the weld pads on the DB6i BMS. This allows more secure soldering of the 28awg silicone wire I soldered between the cut tabs on the new lipo, and the DB6i BMS. I may have justed heat the weld pads off the new BMS and soldered them to the old, but the tab spacing was narrower, that would introduce more risk of heating the pack, and the silicone wire will make it easier to do again next time. The final soldering job is shown in the next photo. You can also see the smaller BMS that came with the new lipo, and the removed weld pads.




Once that was done, I finished it off with a wrap of polyamide tape, done similar to the stock pack. I had some leftover Arctic brand 1mm thick thermal pad on hand. So before reassembly I cleaned off the old white thermal pads and replaced them to ensure optimal cooling (it gets really hot in central Cali).



After reinstallation, I tested it and it works perfectly once again. When that 200mah pack arrives, I plan on store charging it (3.85V to allow some self discharge). It will get stored in the mini fridge I use to store glue bottles. Hopefully I won't need that spare for at least a couple of years.

[edit: Note that 2 of the molded in plastic cylinders that hold the cover screws had broken off (top right on the last photo), likely due to the excess heat in my area combined with the force of the lipo swelling. The stock screws no longer bit into any plastic in those 2 holes. So I used some longer 1.2x10mm self tapping screws to replace them. These screws are long enough to dig into the plastic that remains in the casing. Hope these little details help the next guy fix their DB6i. ]