I want to keep a bit of a lid on this so we’ll call it the e-bicycle build. I bought a pretty big shitter out of excitement. Been dropped and crashed, frame had some ridiculous hole/fix and left outside judging by the rust all over the place and each plastic is damaged. It was cheap enough without the battery but considering the rest of the condition I should have paid like $700 at most(this is still a joke by gas bike standards obviously). But this saved any fabrication, more time hunting and driving like 200km to pick up. But in hindsight I’d take the trip instead of the shitter lol.
I took it to a welder for the frame fix and have been working on it since. I haven’t finished rewiring the lights yet and no test drive. The weather changed completely just as I got it setup it’s like cold and raining now.
It’s a 24S1P LifePO4 EVE 105AH battery with a LLT for charging only.
Controller is a Fairdriver 400A 96V in case this build didn’t work out I would switch to another frame with room for more cells and powa.
Nearly all the space under the tank is empty. I still want to mount the charger under there, I got a variable voltage/amperage one from Ali so not sure how I’d be able to rotate the amperage knob though when using random sockets.
I’m hoping for some really positive results with this build, 100km range at like 80kmh or less would be amazing. The no fire risk with the battery is very relieving.
My bad it’s 32kmh. Canada. I guess 40 would still be ok within margin of error. I really only plan to take it on max 60kmh roads and absolutely no bike paths. I did get a Yamaha Seca II for a proper legal build it just has a functioning enough motor and I feel bad ruining it.
I’ve seen multiple of those around my neighborhood and around my place of work, all ride on the street and the cops don’t bother them as long they use turn signals and respect speed limits aka not be dumbasses, so hopefully it’s the same for you over in Ontario
I think you could find the potentiometer that goes for the amp remove it and solder some extensions to put it where ever you want.
where did you get those ? I’d suggest for you to have something to like hold them tight so that they don’t bulge up badly, I’ve seen a few of those bulge up ending up bending the busbars.
Yeah I think it should be fine here. I took it for a test drive and it’s much more tame actually than the Batbike build. Probably because of the better ratio the belt drive gets vs a hub also only rated 500w.
Regarding breaking out the pot that’s a good idea I thinking that too… It’s a $250 charger that would be modified though. That front face might come off easily.
The batteries are from 18650 store, grade A cells. I’ve read the compression is kind of arguable how beneficial that is? Like some is good to hold the internal components from vibrating and causing the bulging, but not really to force cells not to bulge.
They really should discharge through the top center cap, the casing is a pretty thick aluminum for each one so it’s kind of pointless imo. It’s just to secure the battery in place. 2 sets of 6 then 2 sets of 2 are heatshrunk together with 3 pieces of heatshrink each section, so there is some compression, then with them all stacked. It sucks if it gets ruined though. There are some youtube videos of people buying random cells from aliexpress and they expand on the first charge.
The first charge I was checking for any signs of the whole stack expanding. It didn’t seem to do anything. I used a lower current especially towards the end so it didn’t blow out a cell overcharging that the bms can’t balance fast enough. I think/hope the LLT would stop charging if 1 was over, even if others are pretty low. Which reminds me what’s up with LLT bms having only 70ma balancing current?.
Also the LLT battery app shows all the capacities as low despite the right BMS.
I couldn’t find anything on the datasheet about needing to compress the cells, but it would appear that in their testing that they have them compressed
This video talks about how compression really only helps in the first few cycles on brand new cells. Apparently by squeezing some bubbles which are a manufacturing error out of the platters to the top. This way you can get 3000+ cycles instead of 2500 ish. There’s no way I could easily rig something to apply 300kg of force to the whole pack. It would have to be conditioned out of the bike, a bit too late now. It’s the difference of my battery lasting 250 000KM or 300 000KM on a bike lol. It’s a decent difference but who ever rides a single bike that much?
didn’t really mean to compress them but just hold them somewhat tight but not crazy tight like you should with lipos lol even just to help with vibration and rubbing, feels like it’s just better to have precautions than yolo it and endup have some bulge and wear/tear
If I keep it under 40KMH it’s still good guys!
That front face might come off easily.
It’s the difference of my battery lasting 250 000KM or 300 000KM on a bike lol. It’s a decent difference but who ever rides a single bike that much?