You said your charge port was reading zero volts when the pack was at 19V so there was no voltage increase that we know of. We don’t have any info regarding the pack voltage before you measured the pack directly.
You can’t somehow trip the CIDs for every cell, have the cells sit at zero volts for some period of time, and then have the permanently-tripped CIDs reset themselves and have the pack jump up by 19V.
There are too many unknowns, too many things that are going wrong, too many things that don’t make sense.
What were the p-group voltages (before charging started)?
It’s actually going up right now. It’s at 20.53v, and climbing. I’m 90% sure I measured at the battery as well, as I pulled the tape off of the terminations. If the ESC had anything close to 19v, it would have powered on. I’m quite confident that nothing was broken, and they were just over depleted. It will be interesting to see what the voltage is tomorrow morning. Yes, super happy the ESC is good, thanks.
I didn’t measure the p-groups individually yesterday, and I still haven’t measured them.
A very interesting concept but I still feel it can’t put much long term pressure on the wire and battery contact since the end caps will be pushed away from the cell from the threaded plug’s pressure on the battery contacts.
You can never tighten the threaded plugs more than this amount unless the end caps are epoxied to the cell (and hold during vibration, heat, etc.).
Perhaps having some sort of snap-in or snap-on link between the top and bottom end caps could work?
you seem to be asking for a better design, This is questionably better than the Nese modules, maybe for cost? NESE is smaller and more impact resistant I think NESE, the no solder 18650 battery system.
I’ve seen that system…another interesting method!
Each has its advantages and disadvantages, which is expected of course.
I’m not looking for any particular approach, other than I am anxious to see someone create a great method that multiple communities can use to speed up the building and repair of packs while not affecting safety and reliability.
The kind of complicated and unlimited amount of requirements that require you to go back to the extreme basics of any kind of metalworking, by using welding!
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.
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.
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.
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?
