Personally i’d use hot glue. Easy to remove, makes a pretty durable spacer and its cheap and easy to use
1 Like
Welp… I’m starting to understand why this deck and enclosure combo didn’t work out for Ramm.
I welded the groups this afternoon and tried fitting them back into the enclosure. Still super tight. I pushed a little too hard and ended up ripping the fish paper and the blue battery wrap. I haven’t even had a chance to clear wrap the groups yet and I’m already damaging things.
I hate to admit it, but I think an 18s6p — or maybe even 18s5p — is going to be the better direction for this build. The other option would be taking a grinder to the enclosure, but I can almost guarantee I’d ruin it. I’m just not that skilled with that kind of work.
Has anyone successfully recovered cells after the tabs were already welded? I can’t imagine trying to cut a cell out would be a good idea with all the sharp nickel edges left behind. Can you safely grind down the leftover nickel, or am I basically stuck buying more cells?
1 Like
I’d clearance the enclosure with a wet sponge wrapped in 220 grit sand paper and expend some elbow wrist and finger grease.
Dont pull apart those Pgroups.
2 Likes
It would make sense to sand the enclosure down by hand, but it’s already pretty thin — basically the same thickness as that outer lip all the way around.
I am afraid if I sand it down, I’ll end up removing the fiberglass interior layer on the walls and would need to insulate it again with something anyway.
That is pretty thin.
Disassembling and cleaning cells of old welds and rebuilding is far more work than just building a new pack.
If sanding interior to fit makes it too thin, reinforcing the adjacent exterior is a possibility.
1 Like
If that’s the case, I may just have to pick up some new cells.
Maybe I can find someone to take these P-groups at a big discount and recover some of the loss.
A staggered 18s6p would fit really well…
1 Like
Eve 40PL is a great cell.
7p of 40PL is 28Ah nominal
6P of TenPower 50XG, or Ampace JP50 or Reliance RS50 or EVE 50PL is 30AH nominal
2 Likes
It’s so close that you need to start getting creative. Almost all mu builds are min maxing enclosures like this and it makes them take more time in prep and careful install but can be totally viable and durable. You just need to get a little out of the box thinking going.
You have all the groups fish papered individually, what could you save in width if you Insulated them as a system instead?
Can you make a module that takes up one cell of the enclosure so that you have one layer of fish paper only between voltage differentials? Like fully wrap the center p group, then glue to the adjacent two groups, then apply a single layer of paper just between the cells and the enclosure - will save you two thicknesses of the paper - which is also about what shrink would take up.
Look for the little mm you can save here and there without sacrificing performance or safety, it’s there. Maybe get thinner harder fish paper or figure out how to use tessa tape to insulate. Imho if you have the cells wrapped in shrink and have one total layer of fish paper between them and the enclosure you should be good - if you can have a 1/16th or 1/32 of hard foam to keep spacing it is better. Use some silicone to glue them in or (
) hot glue to stop them from moving around and it should be fine even if it’s tight.
You can also just try to get it good and ride test it - do a short test and open it up to inspect it carefully - pay special attention to any contact points and corners to make sure there is NO movement or damage or pinching. Then do a real long ride and check again. Be very thorough and use a flashlight - look for scratches or shavings or dents in wire or insulation. Take pics so you don’t have to remember if something was there before or not. Then ride hard for a week and repeat. Keep with the half-life increases. And just make it a part of your normal check when you open the enclosure. When you find something correct it.
For glue: in my opinion and experience there are three good options and one bad one
- hot glue, the black hot melt kind. Really quick and easy but not the longest lasting adhesive. Is great for taking up some volume but has difficulty adhering to many cells or smooth plastics as well as not sticking well to cf or gf enclosures.
- Good ol silicone calk. Slow to cure and usually needs 4hrs just to feel like it’s starting to stick. (Neural cure rtv stuff btw - the bathroom stuff is no good because it’s curing byproduct are corrosive). Sticks like all hell to everything, nothing but it will stick to it ever again. No good way to remove it except just scrape and cut it as best you can. I like to connect my cells and cell groups with it because im crazy. I like to think its better because hot glued cells break apart but lots of good packs out there didn’t so maybe just a skill issue on my part. Idc i like silicone
- B7000 - new kid on the block. Slow to cure but sticks like silicone to everything. Doesn’t fill gaps so cant act as a space but once fully cured it is a very secure hold. Good for cells or connecting groups together. Totally removable. Once it’s adhesive is broken you can gently peal it off cleanly without damaging hard materials.
- The bad one: butyl. Shit is just sticky and messy, can be removed but is a huge pain. Cleaning it off sucks, too sticky and forever soft. Amazing for waterproofing or attaching gaskets but no matter what you will use too much and be cleaning it up all the time. When it has to be butyl it just does and nothing else will do - but I hate it.
2 Likes
Dude I really appreciate you taking the time to write all that out. There’s some seriously clever thinking in there.
But I just can’t bring myself to touch this enclosure or cut back on insulation.
If this was something I could easily replace, I’d be way more open to experimenting. But I’ll probably never see another one of these enclosures again. I can buy more cells anytime — I can’t buy another enclosure.
Even if I did get a few extra mm out of the setup, I’d hate knowing the walls are still close against the cells. I don’t want to constantly wonder if something’s rubbing or slowly wearing through over time. That would bug me every time I ride it.
And honestly, I doubt I’d ever notice the difference between 6p and 7p in real riding anyway.
I love the min-max mindset, but for this one I’d rather keep a little breathing room and not stress about it.
1 Like
I made a cute little 10s1p of EVE 40PL. 0.2mm copper, dual 14 awg series connections ,XT90s on 10 AWG
I very much wish that they were 50XG, JP50, or 50PL, or RS50.
Look forward to eliminating future regret.
Step upto 5.0 AH tabless.
5.5 or 6.0ah Tabless Power Cells are a ways off still.
Definitely something to consider! 
Bet that would have made a world of difference on a battery so small.
1 Like
Hell ya dude, that’s the way. Make it how you want it within your comfort zone. That’s what diy is all about
As far as cells, if you reduce the p group count will it be keeping the same stack? Like if you just clipped the extra cell of of each group would you be able to have them in the arrangement and density you want? Don’t let me hold you back if you want to start fresh, just tossing out ideas to save money.
If you remove these three cells from this arrangement it would give you plenty of space left to right. You would just need to snip the nickel clean and re wrap the fish paper. Then maybe shift the center group to the right or left hand position for more room to route the series connections
3 Likes
My regret with the 10s1p of 40PL’s was mainly that i bought them 6 months before I assembled them, and at the time I finally built it, the 5.0ah tabless cells would have added only ~ 20-30 dollars to the total cell cost, and been the same amount of work.
40pl is a great cell, and an impressive performing pack, but 20$ or 30$ more for TenPower 50XG’s would have even less sag, and perhaps deliver 20% more watt hours down to 3.2 volts per cell, AND run cooler, which can mean’ degrades slower ‘
The experience has me regretting not using the best possible cells at battery build time.
So if you can recover some money from those cells, and step up to Ampace JP50 or TenPower 50XG, it will be quite a while before a even more impressive cell is available, and no ragrets later.
Speaking of potential future regret avoidance, we have reports of the K Weld sucessfully welding copper stainless sandwich 
from @braunschweiger
1 Like
What do you think about coating the enclosure with something strong but flexible and liquid in many many coats to thicken it up? Would allow him to sand the inside with a bit less concern.
1 Like
I was a Molicel P42A guy before trying the EVE cells, and the difference between those two was honestly astonishing. The EVE cells run so much cooler, which I’m assuming is mostly due to the tabless design. Just knowing how well that cell performs has kept me coming back to it.
For my use case, anything over a 4p is probably overkill to begin with. I figured since this is an MTB build and won’t be as efficient, a 7p would have done everything I’d ever need with 50% left over. I’m sure a 6p won’t be a big deal either.
I’m overall a pretty mellow rider — I don’t push things super hard — I am just a heavy guy.
That said, I’ll definitely have to consider stepping up to different cells. I may still end up with the EVE’s, mainly due to availability, the small cost difference, and the fact that I know them so well at this point. I think the familiarity and confidence in the cell has some real value when building a battery I won’t fully utilize anyway.
1 Like
Thanks man, totally agree — this is exactly what makes DIY so fun.
I really want to do something like in that pic and give the pack plenty of buffer room so I can really wrap the groups well, isolate the pack, and not feel cramped routing everything.
I heavily considered just cutting a cell off each group, but I kept hitting resistance with every approach I came up with. I do have big shears that would cut the nickel, but they leave pretty serrated, sharp edges. I had to grind the edges down when I cut nickel before, and I really don’t love the idea of grinding around live cells. It just doesn’t sit right with me.
Maybe I’m being overly cautious, but not having that lingering in the back of my mind is worth a lot to me.
I was able to fund the rest of this project with a work bonus, so I am in good shape to lose a little. I threw the 7p groups up for sale — I think they’re already spoken for. If I’m out around $150 from the reshuffle, I can live with that for the peace of mind.
Really appreciate all the tips and ideas though — seriously, thank you.
7 Likes
Got the new groups ready and taped the inside. I’m hoping I can keep the tape down by hitting it with heat whenever it starts to lift. But will look into epoxy/other options if needed.
This was really such a pain in the ass. At least I have something to work on while waiting for motors and BMS from China.
8 Likes
Worth noting that fishpaper is quite absorbent, i think wrapping it over the flange like that could introduce problems with water/damp ingress
6 Likes
Man, I honestly never would have thought of that. Makes perfect sense though.
That lip has been a pain in the ass anyway, I’ll scrape the tape off of at the edges, for sure.
Really appreciate you pointing that out!
1 Like
Fitment of the groups is looking very good. I think you made the right choice 
2 Likes