If you plan to draw current from that pack to the max, maybe not, but otherwise I think it’s fiiiiiine.
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Ok maybe i weld a piece of nikel over it just to be on the save side
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Quick question! What’s your go to place for pure nickel? This was what I’ve found while searching the forum: 0.2mm * 30mm Pure Nickel Plate Strap Strip Sheets 99.96% pure nickel for Battery electrode electrode Spot Welding Machine|Tool Parts| - AliExpress
Is there any place that offers pure nickel faster?
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After burning a whole in my soldering iron with a small short, the battery wiring is done! Not the neatest joints but they’re all strong.
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Not to bag on the idea, but 1Kg is pretty minimal when we’re talking about robust, high current, reliable connections, especially in high-shock, high-vibration environments that can easily see peaks of over 100G.
For comparison, one single M4 screw tightened to spec, exerts over 250 kilograms of clamping force.
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For some applications I think that method can definitely work. Please don’t think I am universally saying it’s a bad idea.
But with the end cap being able to back off whenever the threaded plug is screwed on past a certain point (the static friction strength of the end cap on the cell) I have my doubts that method can handle high current levels and/or shock and vibration over the long term.
I’m glad you posted the vid links though! I am fascinated about clever ideas like this and always enjoy seeing them.
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Hello brains trust,
I got a dead P group that I’ll be looking to replace. When I get my new cells am I right to wire them back up or should I bring each P group up to the same volts IE chard each cell so that they are the same?
Would the BMS do the heavy lifting and sort it out.
Get them to the same voltage. Do you have a lipo charger ?
Yep I have a LIPO charger and a 18650 cell charger too. I was thinking to connect and charge up each P group in the 18650 cell charger. Can I do this for the entire P group or do I need to rebuild?
Can do entire P group. I imagine you only need to charge the new P group to the voltage of the others. The older P groups should all be the same voltage no? On the lipo charger, just change the storage voltage setting to whatever the older P groups are at and charge the new P group to that storage voltage.
Perfect, yep all the other P groups are the same volts. Thanks for advice!
Also if anyone else can comment I would still like to know if the BMS would correct each P group automatically, is this not what the BMS is designed for?
It will but the balancing current on BMS’s is usually like 20ma. It could take days depending on how far out the voltages are. Quicker to just do it before hand the first time.
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No. It should be fine. Mine I cut corners off with scissors and go just to the end of metal on positive sides. Then I kapton tape corners as well afterwards. All metal actually. I’ve had longer ones bend and puncture batteries before. Even had shorter ones where positive metal stuck out still a 1/16". It worked fine. Just wrapped it with Kapton after battery assembly. Then again after wire soldering. Doesn’t look too bad. I’d just throw a piece of kapton over it. Maybe wrap it in fish paper. (vulcanized paper) as well. I do about 8-10 spot welds. Which is overkill I’m told but I’m not risking a board fire mid ride ya know.
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Does anyone possibly happen to know what the diameter of the positive terminal on a P42 is?
Edit:
Negative will also be really useful 
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positive is ~9.5mm
negative ~17.0mm
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Geez that was 10 times faster than all the time i just spent on Google 
Thanks a whole lot!
How much are the measurements off?
Edit: just realized it would be less than 1 millimeter… Forget my question 
Thanks a lot!
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Keep in mind that while the positive measure should not change, the negative measurement will change slightly. That circle is defined only by the heat shrink wrap on the cell, and that’s going to vary from cell to cell.
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Thanks for heads up!