I know boosted uses round cells for their packs. I just recently found out the LiFepo4 can also be made in a polymer pouch form. Has anyone messed with these / knows anything about them?
I heard they sag a lot when discharged at high current. Then again, it was one guy’s post, and no supporting data.
I wouldn’t think so, boosted uses them with reasonable success and gets an okay range considering the power density of the cells.
Although the prismatic format may affect this, but I wouldn’t think it’s likely.
I’ll probably have better luck asking in the EV and ebike forums, they lean much heavier on LiFepo4 because of the cost of their packs and the cell longevity.
I’m not sure but I’ve heard that evolve board use pouch li-ion and they suck balls.
If they exist, they should perform very well and last a long time and be more resilient to damage, but probably be a lot heavier than li-ion
These cells are huge on endless sphere. Ive been reading about them for a while. They’re difficult to terminate effectively because they are aluminum tabs
That’s just because they used sucky cells.
There’s also a difference between pouch lithium ion and pouch lithium polymer. I bet they used pouch lithium polymer.
Also, all those “lipo” pouch cells people get from hobbyking and other sites are not lipos, they are lithium ion in a flat pouch format, they still have liquid electrolyte unlike a true lipo.
Point is, real lipos suck. But flat lion is really good, especially because of the shape.
Yeah, they’re finnicky. I’ve gotten lipo’s before that have an aluminum tab, I had to bolt on a nickel strip.
I’ve also gotten some that have copper tabs staked onto the aluminum tabs by being crimped. The other tab is typically copper as well. Cells that come like this are usually high quality in my experience.
So when I buy a bms from say build kit boards, I should select the liion instead of Lipo?
You should find out exactly what the chemistry is of the cell, and get a BMS that closely matches the voltage parameters that chemistry is safe for.
There’s even countless lion cell chemistries and they all have their caveats
The most common for our high capacity and current are NMC and NCA chemistries, and even mixtures of the two.
If you get the lifepo4 prismatic cells go with a123 . It will cost twice as much as the no name ones but has guaranteed nanotechnology chemistry. Have only read great things of durability and cycle life from these. Same chemical compisition as their 26650 cells that boosted uses but much higher capacities.
I’ve got an earthx battery from an OSET electric trials bike that had a faulty bms, when I opened it up the cells inside are prismatic lifepo. It worked well on the trials bike as part of a 36v system (3 earthx in series) very little sag. The duff battery has been demoted to the power pack for my diy 3000lm bike lighting and is very happy there…
boosted uses A123 cells, they are LifePo chemistry, but very low capacity high discharge ones. that’s why they are so safe, but i assume boosted boards range isn’t that great therefore.
I’m looking into A123 as well. I think with the same size battery enclosure as the boosted you could get more capacity with prismatic cells.
I found some lifepo cells on ebay that reoccur. big and a great deal.
but where would we find real lipos as it seems youre right and what we get from hobbyking have a liquid electrolyte instead of a …polymer. but polymer is a hugely vague term.
Well, the truth is we don’t actually want a real polymer battery.
They kinda suck
But they are a lot safer.
But I think it’s important that we make the distinction between lipo and lion. We’re all using the same chemistry (usually) and we should really only care about the cell specifications, not what kinda package they come in. It’s all the same, just different shapes and safety measures.