Evan's Battery Bonanza

The first line of the thread is dedicated to @jack.luis. Without him, I wouldn’t have been able to do any of this, and without his guidance, I wouldn’t be where I am now. I’m gonna miss you, man. Have fun in Portland, Hoyt is lucky to have you.

Next is dedicated to everyone else that’s helped me along this battery journey. I wouldn’t have been able to do it without you guys either.
(@mariocontino @glyphiks @JoeyZ5 @MrDrunkenMobster @TheRef @Skyart @Battery_Mooch @A13XR3, Sorry if I missed you, only so much I can remember)

Alright, let’s actually get into the meat and potatoes of this.

My ultimate goal has not been decided yet. I’m hoping that I’ll be able to build batteries while in college to fund my own projects and be more independent from my parents. I’m going to start by posting a public portfolio (this) to document my skills and progress. I also believe that I must be very transparent about my skills with any future clients.

Unfortunately, I’m not very good at taking pictures sometimes. Any obvious flaws will be addressed in the caption of those photos as they were likely fixed.

Battery #1 - 12s4p p42a Evo (April 2021)

Everyone has to start somewhere, right?

It started off pretty good, right? I was using some 4p precut nickel and the DBS 4p PCBs. That’s when it all fell apart.
For some reason, we couldn’t weld the nickel tabs down onto the PCB. Nobody could figure out why, so we had to dump a ton of solder on them. I ended up burning through ALL of Jackson’s solder (I obviously bought him more)

Still not too bad, right? It gets even worse.

Now, to be clear, it’s fine for a first pack. The solder joints were solid and held fine, and all of the packs were insulated well. It was just really damn ugly. Here’s a closeup.

So, I don’t have pictures of the balance leads, but we ended up just making fish paper tunnels for them and running them to wherever they needed to go. It worked out in the end, so I can’t complain. I loved that board to death but had to sell it to make space for #3.

Battery #2 - 12s4p p42a Failure (June 2021)

I think it’s really important to talk about failed packs. Battery building isn’t perfect, and this one was full of mistakes. My first mistake was building a pack for “fun”. This pack was really damn long, and looking back on it, there’s no enclosure where that layout makes any sense. I had too much fun with battery #1 and I wanted to keep going.

It started off really well.

Fresh new KWeld was working perfectly, welds were strong, and it looked fairly clean.

This continued on into the rest of the P-Group construction where it was a massive improvement over the first pack.

This is where things went south. No matter what I did, I could not get my solder to stick to the nickel.

It turned out to be a combination of two things.
First, the solder I was using was terrible. I switched over to some quality Kester 60/40 and that helped a LOT. Additionally, my Hakko Presto was getting WAYYY too hot. This was a result of me using a conical tip, which caused me to keep the iron temperature really high. This vaporized lots of the flux which kept it from sticking. This resulted in some nasty series connections (Which I was using a single 10awg for :man_facepalming:) Also you can see I shorted the pack with my soldering iron tip, which melted part of it too. Scared the shit out of me.

Once I got that sorted out, I was left with a bunch of ugly solder joints but a partially assembled pack.

With this pack, I applied a lot of what I learned from #1 and everything I learned from the Battery Builder’s Club thread. I started with this, which only had a layer of FG tape between the leads and the crossing lead.

I eventually undid this and used a fish paper bridge, but I don’t have a picture of that.
Here are some more pictures I took.

The completed pack looked just fine actually. Here’s what it looked like after I shrank it.

Unfortunately, the joy of a complete pack was short-lived.

I eventually realized how stupid it was of me to build a pack with no redundant series connections, sketchy solder joints, and a weird-ass form factor. I ended up dissasembling the pack completely. As of today (Feb 26 2022) those p groups are sitting on my shelf waiting to be further disassembled.

Battery #3 - 12s8p TM3 Kaly (September 2021)

Finally, a good one.
This pack was twice as large as the first two, and my cell choice was making me nervous. TM3 cells are notoriously hard to work with due to their recessed positive terminal and salvage status.

Didn’t take much time to hit roadblock #1. If I staggered the cells, they didn’t fit!

It didn’t take me too long, but I had to disassemble those, remove the glue, and make a nonstaggered double stack layout.

It was going well, and it just kept going well. I was really happy with how this was going.

Nothing really to say yet, it was going great!

Still going great…

aaaand same problem. Wasn’t sticking. I traded out the Hakko for a pinecil and that fixed the problem as I was able to keep the temperature low for the nickel connections (Which were all 12awg or smaller) and I was able to bust out the Hakko for larger connectors and 10awg+ wires. That wasn’t too bad, except some of the solder joints looked pretty nasty after. Didn’t matter anyway, I was fine with it.

aaaand done! Everything circled in red was fixed after the photo was taken. This pack has been rock solid reliable for the past 400 miles, and I hope to see it keep chugging along. This pack was a big win for me. At 500 miles I’m gonna open it up and make sure everything is still solid.

Battery #4 - 12s3p p42a Omakase (October 2021)

This battery was built for @_entropy. It was double-checked by Jackson before I handed it off. It has a fairly simple layout and is not a flex pack, so I was ready to take on the challenge. It was an absolute win.

This picture was not final. I made a bunch of changes and added significantly more insulation, especially for that negative lead. I just didn’t take photos, which is on me. I decided to shrink it with clear PVC as I was proud of those balance leads. This was the first pack I can define as “fun” as it was fairly straightforward (except for that negative connection).

Battery #5 - 12s3p p42a Torqueboards Rocket 33" (March 2022)

Light-ish shortboard for commutes and slower rides.
Insanely fast and stable shortboard!
Abyss | TB Rocket 33 | 12s3p p42a | BN220 | BN Belt | FS6368
Battery was a straightforward flex pack layout with copper braid. Nothing to really write home about. I did fuck up some of the braid and it saturated with solder, but since there’s literally 0 flex im not worried.

Battery #6 - 16s3p p42a Pelican 1150 (June 2022)

This is my MTB brick pack. It’s incomplete as I haven’t put my BMS on there yet. I have an LLT smart BMS going in.

In Progress:

Battery #7 - 7s4p Lishen SA Portable Onewheel Charger (Whenever I decide to get off of my ass)

Building the @mariocontino board bank for a good friend of mine. He isn’t happy with the range of his Onewheel XR. Portable Onewheel Charger | DIY Power Bank for $250 - YouTube

Just started on 2/26 and glued the groups together. Instead of wrapping them individually in fish paper, I did the @glyphiks technique of using the center of the fish paper insulator rings to separate the individual groups.


Battery #8 - 20s7p p42a Ebike Battery (whenever i get money lol)

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What tool did you use to squish the nickel like that to see the cell outline? Pretty neat idea


proud esk8 uncle intensifies
I genuinely wish I was as smart and cool as you are when I was your age. Keep it up, kid. Battery packs are an eternally good business due to international shipping laws. It’s steadily been on my list to start building then, I have my first job that requires it lined up for likely August(dude from England is coming here, wants me to build him a board with travel specced//modular pack so h has something to ride here that he can take home) so it’s gonna happen this year. But as I’m sure youve noticed, battery building services are how smart guys start companies around here. 10 points to Gryffindor.


@glyphiks idea. I just squish it really hard with my finger. Not fun.


Use the back of a sharpie, @mariocontino showed me that trick


That’s probably better than my finger


Use a little skatepark wheel for extra style points.
I already forgot how to small text.


Great post, especially digging that you included some tough lessons as well as your successes. Best of luck with this, but I doubt you’ll need it.


I would like to say that Evan has been quite the student, always happy to accept criticism and improve on his skills.

And kudos to everyone who has helped him along the way :facepunch:


You’re all welcome.



Great work Evan! love the transparency, I have a feeling that this is the start of something really good for you and the community :partying_face::zap::zap::rocket:


Wow you’re really talented dude, just seeing the progression of quality from your first battery build to the latest ones is awesome.
Can’t wait to see some more builds from ya!


Awesome work, are you going to take battery orders?

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Yeah. Soon enough.


Will definitely keep my eyes peeled :eyes:

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How’d I do?

This one was fun, and I fucked up half the braid. Full writeup with pictures will be updated above later.


That braid looks completely soaked and stiff

thats what she said


Yuh I know. First time with copper braid. It shouldn’t be an issue though. Totally stiff deck, it’ll be like folded nickel connections, which won’t be the end of the world.


It might be easier next time to use a wider braid, like 3/8” or 1/2” wide, for small packs you only need one piece, so less cutting/soldering. Also if you get decent quality braid, it won’t soak as fast giving you time to work with it and it’ll retain a bit of flexibility.


Here’s a recent battery @Linny built using the wider braid.