Has anyone built a battery with prismatic cells? Seems like they have potential to be a more energy dense use of space vs the LiFePO4 round cells?
Benefits: they are LiFePO4 chemistry, which is usually safer, suffers far less voltage sag, and can charge and discharge at higher rates. Also, potentially really easy to build a battery, especially in MTB jump pack style.
They also live for fucking forever. Like 6000 cycles.
Something like this with enough in series for decent voltage:
Ive often pondered this. I think theres a YouTuber who used those 200a samsung pouches on a board i remember vaguely it seeming a bit sketch and underwhelming. And if the vgue memory is still serving, im pretty sure someone here successfully and much less sketchily used those batts in ammo cans or the like. Maybe fosterqc or another kinda ek8N og. I intend to use some 40ah samsumg liion to build a 8s1p to use with 265kv 7490 modors. The fucking things are obnoxiously large n heavy but i reckon 8 in a topbox on somin like a flux should be okay. Plus i wonder what could even handle 265kv at 10 or 12s. Charging should take days, i cant wait.
Prismatic/pouch lifepo4 cells bloat unlike cylindrical packaging. Sure you can save space at first but such benefit would be negated once they start to swell.
Sure they have very long life cycles as advertised but that’s kindda misleading. They will last long only with low C application. They gas up fast with repeated high charge/discharge rates. At certain high C application with similar capacity configuration, P42 moli packs can outlast and overall outperform most common prismatic lifepo4 packs.
Many LiPos in the FPV race quad world have compression plates to stop swelling and increase performance slightly, maybe the same technique could be used here? The clamping force might be kinda large at esk8 scales though.
These used to be in my eskate and repurposed after they became too tight for the enclosure. These have vents. I imagine vent-less pouch lifepo4 would be worse.
Advertised 30Ah, 100A continuous discharge, +2000cycles @ 80% DOD… but only lasted around 40cycles before this happened even tho I only drew 80A max.
I use LiFePO4 a lot in the boards I use daily, mostly because they’re safer and last a really, really, really long time.
But they don’t have less sag, they have more. It just feels like they have less sag, because the sag is rather constant throughout the whole charge cycle, so the board never really feels “sluggish” compared to when you took it off the charger — until a couple minutes before it’s completely dead.
And feeling like less sag, might as well be less sag.
You get everything with LiFePO4 — except high range. They’re perfect for commuter boards {used for transportation}.
I run some packs in Apache cases built with pouch/prismatic cells … but Li-Ion chemistry, not Lifepo4.
Currently in service are…
– Two instances of: 10s1p SPIM08HP (8Ah, weighs like 4 kg [10 lbs] in the apache case) like @Fosterqc has used… these seem to push 100A fine.
– One: 10s1p Stoba that @Fosterqc linked above (19Ah, weighs like 8 kg [20 lbs] in the apache case)… but I dont run this pack alone cuz its only good for 40A discharge. I pair it with one of the SPIM08HP packs to share the load.
Since you mentioned Lifepo4 A123 prismatics, I have noticed different form factors. Check these out…
The patent for the LiFePo4 runs out after newyears, alot of chinese factories are ready to spew out cells for cheap when it does. So might want to hold of for dirt cheap prices in spring
Some skinny boys (<.5cm thick). Only 6Ah.
I googled the marking that appears to be the A123 Systems model number (AHP6AU1-A) and found no substantial info.
They look similar in form factor to the 20Ah versions in the OP. Could make sense for a top mounted battery. Tricky to fit under deck.
