Dui, ni shuo de dui wrote: ↑
May 09, 2018 3:11 am
-It would imply that I'd have to somehow machine busbars out of aluminum or copper. Not a big problem but I'd need something like 95 of them so it would be quite a bit of work
Once you work out the design, you could have them waterjet-cut by places like Bigbluesaw here on the forum, or any number of others.
As for the number of bars, is it really a 95s battery? (or 93s, with another bar at each end). Thats a lot of voltage.
If its instead the battery you describe in the OP, a 24s 4p, you only need 24 (26) busbars, because each bar would be 4 cells wide, kinda diagonal to go between the + of the lowest cell to the - of the highest.
-I'm not a big fan of screwed terminals in a vehicle that will experience a lot of vibrations, thermal variation and stuff like that, Sure I could use some thread locker but I would always be a bit worried that the connectors would loosen up at some point
-3D printed plastic parts are rather solid, but the clamping force needed is rather huge, so I'd worry a bit that the inserts would slip in the plastic bracket while tightening...
If the inserts have knurls or are otherwise not round, they wont slip, if theyre molded in. If you can find pics of the EIG hardware (theres some here on ES, and elsewhere) you can see how they did it.
Though the screws have standard split-lock-washers I didnt put threadlocker on the screws in my 14s1p EIG pack, and it stayed tight for the years I used it on our bumpy potholey roads, on my hardtail bike and trikes. It still sees occasional use but I tend to use one of my 14s2p packs instead, which also dont use threadlocker (I think I left the splitwashers off on the pack thats built into SB Cruiser, dont remember for sure). Ive only had them for a year or two, but again, no loosening so far.
I dont have to crank them down further than a 2mm allen key will tighten the ~3mm-wide fine-pitch screws without stripping the key or head or flexing the key.
-It will add quite a bit of weight and would probably less compact, my battery box is only 26cm wide, which is one of the main problems I have.
It will add some weight--how much depends on the thickness and metal you choose for busbars, which will depend on the current you need them to handle. But I dont think its that much weight. Maybe a pound or so if you use really thick copper. I recommend using the same metal as the tabs or tab extensions, to eliminate the possibility of electrolytic corrosion.
It shouldnt add significant height to the pack, perhaps a few mm depending on the thickness you already have for the mounting plastics and the thickness you choose for the busbars, and wont add any width unless you change the plastics width. The thickness simply has to support the pair of nut-serts per tab, or actual nuts if you go that route.
If you add welded copper, brass (or other) extensions to the tabs (to prevent electrolytic corrosion between differing tab metals, if the plus and minus tabs are different) then that may add some height, depending on how closely theyre attached to the cell on the tab.
-I believe it would add a bit more resistance than soldering (but I'm not entirely sure about that particular point)
Since solder itself has resistance that is probably a lot higher than direct contact between tabs, the only potential issue I can think of is if moisture can get between the tabs in the clamp, and cause electrolytic corrosion between dissimilar metals. As long as you use tab extensions of a single metal, that wont be an issue, or if the tabs are already the same metal.
If the tabs come wrinkled instead of completely flat like new ones, you may want to use a press to flatten them first to be sure they mate completely across their surfaces.