I wonder if all the foam you use is worth it as opposed to just a tightly fitting box and glue.
I’d take off the big shrink wrap holding the lipo cells, put fish paper between the plugs/wires and cells, then put it in a tightly fitting box I’d fill with like 80a duro rubber. ( silicone would transfer heat better or could add to the resin with talc or something to transfer heat.) pour on top. Let it overflow. The lid sticks on.
I’m not saying potted in a box is better but could be and save a lot of space.
Between the bms and battery the foam could be replaced with something thin and hard. the crash force is very unlikely in the z-axis.
The outer shell of foam you don’t show but I imagine would similarly fill the rest of the box shape.
If you take the plastic shrink off a lipo and pot them in a box of resin (not 2-part silicone that doesn’t stick) … the cells themselves are then being held “all over” and less likely to crumple in a crash … I believe.
I think in the majority of cases, no it isn’t worth it. I’m using it because I think there’s a lot more room for error using foam in comparison to this method:
If I were to make a mistake (which is quite likely) using this method, repairing that mistake would be much more difficult. With foam I can just remove the tape and correct my mistake.
This i hadn’t taken into account though, good point!
A large part of why I’m using as much foam as I am is to accommodate an unnecessarily large pelican case I already have. The battery is only about 450wh of lipos and doesn’t take up much space.
A substantial amount of the foam is more intended to keep the battery from moving around which I’m realizing now would be wiser to secure to the enclosure rather than the battery.
I think that the pvc I was using Morphus stability, but I have the foam padding in between the two sides and well I didn’t actually I was going to run full paper on all of them, but then I looked at. I was watching the robot video to protect that way, but the cells are staggered also so they won’t move like the pack of solid now, but I didn’t like I didn’t have to run that way to begin with. I had a different image in my head. I was confused about how to run because I couldn’t do parallel with the length of the enclosure which threw me off and I threw my whole mixed up the group so I inspected the first BMS under microscope and yeah, it was just every other one was every other chip was a little brown. Could’ve been worse you know , I see I did a visual. I don’t see how you know I mixed it up. I think it was just cause I’m I started off with the wire was instead of where there wasn’t one with the actual beginning of the Cell was I have planned soon. I’m not happy with this. I do however feel that it’s 10 times safer than my first build and it will hold up , appreciate you guys input guidance want to do next
I was really proud of my original balance leads. Ran them out of sight all the same length didn’t cross up and good solder points. My first pack I cut the ones with extra to reach the further ones I believe I actually had to glue a couple bc I could not get a good solder point. I just have to mount my charge port and figure out how to mount these rockstars to the bn gear drive and I’ll finally be rolling yerpp
Yeah, I think you have protection between the two sides. looks like foam and some kinda FR4 or the like.
The thing I was commenting on is between the pairs of cells welded together, ie between each pgroup. that last pgroup looks fully wrapped in fishpaper which protects it’s sides from the next pgroup. putting fishpaper between pgroups is a good idea. pvc wrapper and hot glue will be much less abrasion resistance. and the cans of cells one pgroup can short against than the cans of the pgroup next to it.
you mentioned in the video… realizing where the pack total negative, and pack total positive actually were.
I always buy a cell or two extra for drops and tests. Every manufacturer and even by batch the exact settings needed seem to shift around a bit so I sacrifice one to skaten in the hopes of building a “no repairs ever, outlasts me” pack. Otherwise keep an eye out for something dead with cells in it you can repurpose like a laptop or tool battery that’s dead. Also ask around because people are lazy and wont recycle them and will have them lying around.
If you’re near Seattle i have a generous pile waiting to be scrap that i use for test fitting and weld tests i can get to ya. If you’re willing to pay shipping i could mail you a couple - but the easiest way is always to just keep an eye out and they’ll pop up.
Unrelated to battery building but you need 5mm~ longer M4 wheel screws than the ones that come with the wheels. Those metal pegs screw onto the exposed/extra thread sticking out the inside of the wheel (since they are longer than stock). They interface with the black plastic wheel adapter plate that’s mounted on the gear drive.
I got it man thanks that’s exactly what I was needing. I’m so close to being ready to ride this board. I’m trying to figure what the discharge and charge mps max should be in Vesc tool
The motor max discharge amp setting is limited by heat in the motor. The battery max amp discharge setting is limited by whatever the cell data sheet says.
Motor regen amps u again are limited only by the motor temp. Battery max regen people go beyond what the data sheet says is the max charge rate because brakes are more important than cell longevity and it’s only generally a very short time period the brakes are used hard.
Motor discharge and charge settings are in effect when at slow speed and battery charge n discharge settings at high speeds
Hell yeah thanks man I’m working on it now. I’m looking at this trying to activate my Bluetooth on my maker XD 100 S and Vesc tool is saying I have an update my firmware to use that setting but whenever I look at it, there’s no firmware to to update to. That’s what Google say also but o could be missing something. I have the Vesc wand, I’m trying to figure out how to pair it. the flipsky was a nightmare I finally figured out how to do it. I wonder if there’s a trick for this one as well
Its from a recent LLT BMS, I wanted to run my own cables (which I have) but cant find spare connectors for the life of me. Any guidance or kick in the right direction would be appreciated!
JST-PH might work as a stop gap measure + a bit of adhesive/binder (glue) to keep things secure but I was more looking for a direct replacement with the latch/buckle.
This was closer but appears to be a 2x15 connector - Ill take this as the kick in the right direction as I was focused on Digikey and Mouser as possible options to find the connector (also focused mostly on some JST model/sku that I just could not for the life of me find).
Looking up the A2005H I did find my way over to LCSC which I didnt check for options. Granted I still need to measure the pitch before I order, these two look pretty damn close.
X2011HM-15A-N0 (Very similar buckle, seems like it would work without issue)
ZX-HY2.0-15PJK (Appears to be the exact same buckle complete with the two fangs/nipples on either side of the buckle and the indexing wings on toward the edges of the connector).
Thanks for taking a look both of you, much appreciated!
It is not available on digikey or mouser, last I checked. When I was working for Hoyt, I had to source them directly from china, with a pretty high MOQ. Good luck and godspeed.
