CTX-3030 Metal Detector Battery Fault - BQ20Z70

[Barry Klein]

I and another guy have been looking at rebuilding bad battery packs for this metal detector. There is a video on youtube on replacing the cells and good to go. I did that on my old pack and it worked great. The problem is that perhaps there is a new circuit or something as rebuilds are not working as often. It seems the BQ part does not turn on one of the FETS. There is a weak connection to the pack output - the cells read about 7.4V but the pack 6.7V. We can force the FET on and the pack has correct output and the detector works with it. The BQ part is supposed to be programmed with factory optimized firmware. I suspect a new BQ part will not work because it won't be programmed. Anyone have any experience with this sort of thing? Should we just ditch the battery management board and get another from China? The pack uses 18650 cells in a 2P2S arrangement.

 

[davenn]

It seems the BQ part does not turn on

what is that ??

photos/circuit will helps us all help you
really difficult to visualise without seeing what it is all about

 

[Martaine2005]

BQ20z75

Why didn't you post that info first?
BQs are not a normal way to describe something.
You could have and should have said what the item is and the part number.
www.ti.com/product/BQ20Z75-V180

 

[bertus]

Hello,

There seem to be several versions of the BQ device:
http://www.datasheetdir.com/BQ20Z75-V180+Battery-Fuel-Gauges

Did you get the correct version?

Bertus

 

[Barry Klein]

Why didn't you post that info first?
BQs are not a normal way to describe something.
You could have and should have said what the item is and the part number.
www.ti.com/product/BQ20Z75-V180

Did you read the post title??

 

[Barry Klein]

Berry’s, the other guy tried a replacement part but no change.
There is an exhaustive process to come up with a charge/fuel gauge profile that the factory (Minelab) must do. Hundreds of pages of documentation.

 

[Martaine2005]

Did you read the post title??

Admittedly I did not, as my phone does not show the full title.
Most people prefer to get the specifics from the post content.

I too replaced the BMS in my XP Deus.