Time for an update guys, here we go. Hope some people find it interesting because this took a ton of work! I am enjoying riding it so far and it has given me a lot more kick.
The upgrade: BMS + charge port, additional 3P of batteries, better mid enclosure, bluetooth module.
First thing is first - here’s some more information about the batteries I received. @KaramQ was kind enough to pass off 3 batteries from old landwheels & the first generation of the revel kit batteries that used the same cells as the l3-x. Upon receiving them during the summer, I didnt’ have much time to a whole lot with them except disassemble them into their pouch form.
This procedure was annoying as ever, but at least this time I knew what I was doing since I had done it before. Open the battery case, hack out the cables and lipo pouches, desolder the circuit board, rinse and repeat. Here’s some pictures of the disassembly:
These early version Revel U batteries had the same exact layout, BMS, and pouches as the old L-3X ones; this makes sense because the battery enclosures and interface were exactly the same as well. Given that I had 3 batteries and had already purchased the BMS, I was set on going with 8s. After opening them all up and removing the dead cells, I looked back in my inventory from the first time I had disassembled the original batteries, remembering that I had set aside the last few leftover good ones from before. To my dismay, I was only a couple short of being able to do 8s7p, or 10s6p, so I had to go with 8s6p, which isn’t bad considering I started with 8s3p from the original pack I had already made.
I don’t really recommend what I have done here as it is kind of dangerous, but here are the cuts I did to get the batteries out. These pouches are pretty well secured into their enclosures with silicon? adhesive on most of the sides. To get around this, you can cut the plastic out and bend the case to remove the cells. In addition to the silicon, the entire inside bottom of the enclosure is covered in double sided tape.
Step 1, cut out the latch area, pretty easy since the cells aren’t real close to it.
You can see that I have started to do the second and third cuts, branching out to the sides, along the vertical walls. These are very dangerous cuts because sometimes the batteries go right into the corner near the screw posts. I actually nicked a little bit of once of the cells when I was cutting and freaked out but fortunately it didn’t pierce all the way through.
After the branch cuts, you can slide down the sides, along the wall, to separate a lot of the silicon from the base and the cells. It is a pretty simple cut but you still need to be careful - this might be a good time to mention that I made all of these cuts with a dremel and the plastic cutoff wheel.
Here’s a top view of what it looks like with the front and the sides removed. After this step, you can peel the baseplate away and bend it down, sort of forcing the battery off of the double sided take and ripping away the remaining silicon.
Here’s a view of the second battery, with all of the cuts made at once. This is the one I nicked a bit I believe, since I was trying to make it go a bit faster.
Again I don’t super recommend doing this if you aren’t experienced with your dremel because sometimes the cutoff wheel catches in the plastic and goes deeper than you intend.
After separating the case from the cells, you can then remove the BMS carefully, slowly peeling away the adhesive so as to not cause weird pulls on the cells. Following that, the cells can be separated with the floss technique that I mentioned before.
For this part it is quite easy to cut your fingers on the floss, even though I was using screwdrivers to hold it, I found a few cuts on my fingers after separating all 30 cells.
Here’s all the good cells laid out and the extras, labeled with their voltages and eventually their polarities. You can see that they were mostly even, but with some variation within a reasonable amount. Their dead cells were seriously dead, like 1.5v or lower.
At this point I put the project on hold until I got to school and had some more time. (AKA until I found something to procrastinate on and do this instead.)
