No flex there whatsoever, the whole thing can be fairly brickish
A shame to butcher @glyphiks lovely 12s8p but nobody wants a single stack 12s8p so forced to split it. With some guidance, and some sloppy work it’s almost done.
A local racer will be using the pack on the right for a 4wd racer and the pack on the left will go in the Frankendick build (for anyone following that thread). Happy days.
3 Likes
Not strong enough
Damn. Of course amazon would lie about product specs. This was on max power
1 Like
If you put a second nut on one end then yes
3 Likes
Might be the battery you use, you need to pull about 1.5 shit tons of amps. I would suspect the battery IR just wont push what you need and the welder is no t able to finish the job. Try mor battery mor better before mor welder
I got a123 lifepo cell pack (4s8p) cheap but large. (Came from batteryhookup emc server pack)
So pretty cheap and safe.
For lipo, a 15ah 3s pack has also been geat for me.
1 Like
I burned up a sunko spotwelder when the kweld existed .
So Don’t feel bad if you get another one. You pay the diy tax sometime, somewhere.
1 Like
Ok so I may have used slightly too much insulation.
Neutral core siliconed the cells, fishpaper, fibreglass, polyimide tape, then pvc shrink wrap and finally Teflon tape for the deck and enclosure.
4 Likes
What do ppl tend to do for the balance wires at the bms end? It seems redundant to spend the time taping them on top of the battery if they are all floating at the other end ?
My personal thoughts on it are that overlapping on the battery makes it easy to short two wires with just pressure. The insulation on most of the conductors used is kinda garbage and warm (not hot) and a little vibration can compromise them easily. Free air and with nothing hard pressed against them outside the pack is a lot lower risk.
This is also where i cross and uncross my cables when doing 2-3row type builds - criss crossing at a 90 degree bend as they sweep into the headers. I have been wrapping them in tesa tape (the fuzzy kind not the smooth kind) to give them some structure and abrasion resistance here but i have not seen any use and vibration damage to this section of the conductors except where someone had accidentally damaged them during maintenance.
breaks and damage to the wires on the pack i see: (but this is just my experience fixing and tearing down stuff) right at the connections to the cell - i think it’s usually that the wire isn’t supported far enough down its length or has no strain relief on it at all and breaks due to vibration. where the wire was stripped (probably a small nick in the copper from the wire stripper making a weak point) or just a bit further into the insulation where the solder has wicked up the conductor at the interface between the soldered and clean conductor.
I started using this black hot glue or silicone on the connection and down the wire a cm or so. Time will tell if it is effective
6 Likes
What’s the low voltage threshold beyond which a cell is no longer safe to use?
I’m seeing numbers from 2v to 1v. Different lithium ion chemistries could be different as well.
(Assuming the cell would be charged back up with a very low current)
P42a and liIon type i abandon them to scrap when they hit less than 2.5v. Even if they could be restored i personally will never support reviving them below that. It’s not worth the risk imho. Other chemistries i would check the data sheet and use the minimum discharge voltage as the bottom but im not an expert
1 Like
What if you assess them?
How you decide on 2.5v? In my looking all I could find was 2.0v to 1.0v limits. But I can’t find any real data to support anything.
You can assess them based on resistance, holding a charge, …but is that the full revelation
Why do I have a feeling you knew the answer but wanted to disagree with the common knowledge for fun, again?