IAmATeaf
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- Joined
- Jul 19, 2015
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- Viofo A119 v3
I have an old multimeter which can be powered using an external PSU and via 6 C cell batteries. The external PSU I use is 6v but the meter can accept anything from 5v up to 15v. Internally the 6 C cells are in series so 9v in total. When the external PSU is plugged in it effectively disconnects the negative of the internal battery pack via the PSU jack when the PSU is plugged in.
Now what I wanted to do is replace the internal battery pack with some 18650 batteries that I have spare, the plan was to use 4 batteries, 2 in series then the pair paralleled together. So I’ve ordered a 2S BMS board and the required better holders.
The BMS has connections for B+ and B- and BM which will go to monitor the individual cells. This is where I’m getting a little confused, the BMS only has P+ and P- which from what I’ve read serves as the charging supply and the output. The minimum charging voltage is 8.4v so if I understand it right the BMS must detect voltage over 8.4v and flick it into charging mode?
My plan was to replace the existing 6v PSU with a 9v PSU which could then be used to both externally power the meter and to also charge the batteries.
This is where I’m getting confused, with the existing power jack on the meter when the external PSU is plugged in it disconnects the negative of the internal battery so how would/could I wire it so that I can use the external PSU to power the meter and to charge the new batteries.
Could safely rewire to not disconnect the internal battery negative so that way both the meter and BMS are connected when the PSU is plugged in or must I disconnect the load when charging?
Any help would be appreciated.
Now what I wanted to do is replace the internal battery pack with some 18650 batteries that I have spare, the plan was to use 4 batteries, 2 in series then the pair paralleled together. So I’ve ordered a 2S BMS board and the required better holders.
The BMS has connections for B+ and B- and BM which will go to monitor the individual cells. This is where I’m getting a little confused, the BMS only has P+ and P- which from what I’ve read serves as the charging supply and the output. The minimum charging voltage is 8.4v so if I understand it right the BMS must detect voltage over 8.4v and flick it into charging mode?
My plan was to replace the existing 6v PSU with a 9v PSU which could then be used to both externally power the meter and to also charge the batteries.
This is where I’m getting confused, with the existing power jack on the meter when the external PSU is plugged in it disconnects the negative of the internal battery so how would/could I wire it so that I can use the external PSU to power the meter and to charge the new batteries.
Could safely rewire to not disconnect the internal battery negative so that way both the meter and BMS are connected when the PSU is plugged in or must I disconnect the load when charging?
Any help would be appreciated.