bms and spot soldering - safe or not ?

[mavicmodx]

I want to ask if spot welding is safe for the bms of the mavit air 1 battery?

 

[GFields]

Spot welding? What is there to weld on a Mavic 1 battery?

 

[Yorkshire_Pud]

Allowing for translation issues probably spot welding might mean soldering.

That said @mavicmodx
I'd be wary messing with the BMS especially if you are replacing batteries. You may need to create temporary connections to new batteries in parallel to the old batteries BEFORE you disconnect the old batteries. AND THEN keep those temporary connections to the new batterie in place until you have the new batteries properly connected.
If you do not do that and the 'gas gauge?' sees 0 or too low a voltage then it may switch off, or switch off what ever it controls, and then the battery/BMS is effectively dead ....... unless you have the equipment and software? needed to reset things.

If you are talking about repairing a broken circuit track then you are going to need some very precise soldering skills. I think I have bridged a broken track somewhere by tacking a single strand of copper wire to one side of the break and then to the other side and then run the soldering iron and a vein of solder along the strand but if so that was on an older circuit board that was MUCH less densely packed than modern circuit boards.
If it's a surface mounted component that has broken a solder joint then I think you face 'fun' with a simple soldering iron and would probably need to used a magnifier of some sort to see what you are doing and check that you haven't bridged something that you should not.

 

[mavicmodx]

Allowing for translation issues probably spot wilding might mean soldering.

That said @mavicmodx
I'd be wary messing with the BMS especially if you are replacing batteries. You may need to create temporary connections to new batteries in parallel to the old batteries BEFORE you disconnect the old batteries. AND THEN keep those temporary connections to the new batterie in place until you have the new batteries properly connected.
If you do not do that and the 'gas gauge?' sees 0 or too low a voltage then it may switch off, or switch off what ever it controls, and then the battery/BMS is effectively dead ....... unless you have the equipment and software? needed to reset things.

If you are talking about repairing a broken circuit track then you are going to need some very precise soldering skills. I think I have bridged a broken track somewhere by tacking a single strand of copper wire to one side of the break and then to the other side and then run the soldering iron and a vein of solder along the strand but if so that was on an older circuit board that was MUCH less densely packed than modern circuit boards.
If it's a surface mounted component that has broken a solder joint then I think you face 'fun' with a simple soldering iron and would probably need to used a magnifier of some sort to see what you are doing and check that you haven't bridged something that you should not.

Yes, "spot soldering" sorry I want to replace the old cells, and I see that the old ones are not soldered with tin... looks more like factory spot soldering to me.I have the software + hardware to unlock the battery/bms.
not sure how to clamp the new cells though, tin doesn't seem very tight to me.
and with spot soldering I don't know if I won't damage the bms. I will use cheap china 12v spot soldering tool (20$).

 

[mavicmodx]

Spot welding? What is there to weld on a Mavic 1 battery?

spot soldering

 

[Yorkshire_Pud]

If your "tin" is real tin then from memory tin will 'take' solder, test it on the distant end of one of the tin strip. Somewhere I have seen something similar to what I think you describe.
If the tin strips are the large current conductors then what would happen if you cut them and left only small stubs of tin strips attached to the BMS board and then soldered the large current wires from the new battery cells to those stubs?
Or if the new batteries also have tin strips, after cutting the strips to appropriate lengths and solder what is left of the new strips to what is left of the old strips?
Or cut all the strips down to short stubs and then solder suitable wire between the stubs.
SPACE might be a consideraton so check whether or not there is enough space for wire before cutting the strips.
I would be wary of trying to break or unsolder spot 'joints', be they welds or solder joints, you might physically damage the track/s to which they attach.

 

[AMann]

I know on the Mavic 2 batteries, the BMS will shut off permanently as Yorkshire said if you disconnect power to it. As suggested above, be sure to supply the same voltage as the cells do in parallel before you disconnect the old ones.

 

[mavicmodx]

I know on the Mavic 2 batteries, the BMS will shut off permanently as Yorkshire said if you disconnect power to it. As suggested above, be sure to supply the same voltage as the cells do in parallel before you disconnect the old ones.

I can unlock it.

 

[mavicmodx]

which 18650 can be replacement cells in the battery ?