Ianmac52
Ianmac52
Hi
Started building battery packs with harvested 18650's. I think I know where I am going wrong but would like some like minded person(s) to comment.
The basic problem is that when I spot weld the packs I have ended up with a number of pinholes in the negative end of some cells.
This is the first time I have harvested cells so I figure mistake 1 was to use a dremel with a fine grinding wheel to remove previous spot weld tags. I can see that they would work on having a minimal amount of metal thickness for the casing so I have probably shaved a bit off thus making them prone to holing.
The second thing is the welder, it is a d.I.y. one (groan) using a 12 volt battery etc. My original intention was to fit a timer to limit the number of milliseconds of power to each weld, but I managed to brick the timer going through all the permutations of connections as there is no manual available. So the weld time is governed by the user and on occasions was probably a couple of milliseconds too long. I have another timer on order but it is weeks away and I had to scratch that itch so to speak.
I am guessing that the pin holed cells would be deemed potentially dangerous so these are being removed.
Would the consensus be that I am right or is there something I have not considered.
Started building battery packs with harvested 18650's. I think I know where I am going wrong but would like some like minded person(s) to comment.
The basic problem is that when I spot weld the packs I have ended up with a number of pinholes in the negative end of some cells.
This is the first time I have harvested cells so I figure mistake 1 was to use a dremel with a fine grinding wheel to remove previous spot weld tags. I can see that they would work on having a minimal amount of metal thickness for the casing so I have probably shaved a bit off thus making them prone to holing.
The second thing is the welder, it is a d.I.y. one (groan) using a 12 volt battery etc. My original intention was to fit a timer to limit the number of milliseconds of power to each weld, but I managed to brick the timer going through all the permutations of connections as there is no manual available. So the weld time is governed by the user and on occasions was probably a couple of milliseconds too long. I have another timer on order but it is weeks away and I had to scratch that itch so to speak.
I am guessing that the pin holed cells would be deemed potentially dangerous so these are being removed.
Would the consensus be that I am right or is there something I have not considered.