Where This Build Guide Comes From

Every step in this article comes from one source video — EbikeSchool.com’s New & improved Vruzend V2.1 no-weld 18650 kit, which has been watched more than 570,000 times. In the video, Micah builds a complete 36V 10Ah e-bike pack (10S3P, 30 cells) using the Vruzend V2.1 solderless kit — no spot welder, no soldering iron — and walks through the dovetail caps, the barrel bolts, the figure-8 bus bars and the 10S BMS wiring in order. If you would rather watch the build before reading the breakdown, the video is right here:

EbikeSchool.com — “New & improved Vruzend V2.1 no-weld 18650 kit”
Watch on YouTube →
570K+ views. A 36V 10Ah e-bike pack built entirely without welding using the Vruzend V2.1 solderless kit — 10S3P layout, barrel bolts, figure-8 bus bars and BMS wiring.

Why Build a Battery Without Welding?

Spot welding is the standard way to build an 18650 pack, but it is also the barrier to entry: a decent welder costs money, nickel strips are consumables, and a single bad weld is a connection that will fail months later under vibration. The Vruzend approach replaces welding with mechanical contact — each cell sits in a dovetail cap with a spring-loaded contact, and bus bars bolt across the tops. The result is a pack you can assemble at a desk with a hex key, take apart to replace a single cell, and rebuild with different cells whenever you want. For builders who make one pack a year instead of one a week, the solderless route removes the most expensive and most dangerous step from the process.

The trade-offs are real and the video is honest about them: the kit costs more per cell than nickel strip, it is not the right tool for mass production, and the builder still has to plan the cell layout and BMS wiring carefully. But for a single custom pack — an e-bike, a wheelchair, a solar project — the ability to rebuild and service it is worth more than the price difference, and that is exactly the audience the video speaks to.

The V2.1 Kit: What Changed From V2.0

V2.1 is an incremental but meaningful update. The caps are redesigned so they seat more easily and hold the cell contacts more firmly, and the kit now uses barrel bolts — the long bolts that run through the cell stack — to apply continuous compression across the whole pack. That last point is the headline feature: instead of relying on individual caps to stay tight, the entire stack is squeezed together evenly, which keeps every cell contact under constant pressure even as the pack vibrates on a bike frame or a wheelchair.

Micah’s advice on the barrel bolts is specific and worth quoting in spirit: distribute them evenly through the pack, you do not need one in every slot, and do not overtighten them — too much force will push the caps open and break the contact rather than secure it. The compression should be firm and even, not cranked down. This is the same principle as prismatic-cell compression in a large LiFePO4 build: controlled, even pressure beats brute force.

The Build: 36V 10Ah From 30 LG MJ1 Cells

The video builds a 36V 10Ah pack: 10 cells in series (10S) and 3 parallel strings (3P), for 30 cells total. The cells are LG MJ1 18650s — a popular 10Ah-class cell with a good balance of capacity and current — and the pack math is straightforward: 10S gives 36V nominal, 3P gives 3× about 3.4Ah per string, landing right around 10Ah. This is the classic e-bike form factor, and the same layout scales up or down by adding or removing parallel strings.

The assembly order is where beginners usually go wrong, and the video slows down for it. The caps mate with a dovetail-and-socket arrangement, and every cap in a row must face the same way — if you flip one cap, the dovetails point the wrong way and the cells will not slide together in series. Lay out the whole row, check every cap orientation, and only then start seating cells. It is the kind of five-second check that prevents a twenty-minute rebuild.

Figure-8 Bus Bars and the Short-Circuit Trap

The bus bars in the Vruzend system are the little metal strips that bridge cell tops, and the video’s pattern is a figure-8: each bar connects two adjacent cells, and the trick is that series connections and parallel connections alternate and must never touch. When you lay the bus bars across the top of the pack, series bars and parallel bars sit at different heights or orientations — and the instant one of them bridges the wrong two contacts, you have a short circuit between cells. The video’s rule: flip the figure-8 bars over deliberately (one side for series, the other side for parallel), and double-check the layout against the diagram before you torque anything down.

This is the same lesson as every DIY battery build, just in a different format: the connections are the whole game. A welded pack hides its wiring mistakes inside the nickel strip; a solderless pack shows them to you on top, which is honestly a feature — you can see and fix your own error before power ever flows.

Wiring the 10S BMS

The BMS wiring is the one part of the build where a mistake is expensive, and the video walks through the order explicitly. The black wire connects to B- — the pack’s overall negative — and then the balance wires follow the series chain: count even-numbered cells in one direction, flip the pack and count the odd-numbered ones to finish, so every cell junction has its own sense wire in the right order. Micah’s advice is to reference the BMS wiring diagram that ships with the unit, not your memory, and to label the wires as you go.

A soldered pack has the same requirement — a 10S BMS needs 11 sense wires in exact order — but with a solderless kit the balance wires terminate on the same bus bars you can see and reach, so a wrong connection is a five-minute fix rather than a desoldering session. For first-time builders, that serviceability is the real reason to consider the kit: the wiring is no simpler, but the consequences of getting it wrong are far cheaper.

Insulating the Pack: Kapton, Foam and Heat Shrink

A bare 18650 pack is a fire waiting for a bridge, so the video’s finishing steps are about insulation. The cells get Kapton tape and foam strips between them — the foam absorbs vibration and the Kapton prevents a scratched wrapper from shorting against its neighbor — and the whole pack is wrapped so the coverage is 360 degrees, not just the tops. Heat shrink then goes over the assembly to hold everything together and keep metal out. The video is explicit that the insulation is not optional: a pack that will live in a vibrating, weather-exposed spot like a bike frame needs every exposed surface covered.

This is where the kit’s target uses shine: the video lists e-bikes, electric wheelchairs, and even an electric umbrella motor as builds owners have completed with V2.1, and the beta-testing history includes an SRM University electric racing car and a solar car project. The common thread is vibration and rebuildability — exactly what barrel-bolt compression and screw-together connections are designed for.

Solderless vs Welded: Which Build Is Right for You?

If you are deciding between a solderless kit and a spot welder, the honest answer is that it depends on your volume. Building one pack for your own e-bike or wheelchair: the Vruzend kit wins on safety, tool cost and rebuildability — you can replace a single worn cell instead of rebuilding the whole pack, which the video’s comment section repeatedly calls out as the killer feature. Building packs regularly, or building for other people: a spot welder is faster per cell and cheaper per pack at volume, and welded connections are more compact for tight enclosures.

The video also settles a common worry: vibration. The original V2.0 users’ fear — that screw connections would rattle loose on a custom e-bike — is exactly what the barrel bolts in V2.1 address, and builders in the comments confirm the fix. One long-time user who has owned every version notes the earliest kits still power his yard lights charged by solar, years later — which is as good a durability testimonial as the format allows.

Our Verdict on the V2.1 Kit

For a first-time builder or a one-off custom pack, the Vruzend V2.1 is one of the safest ways to get into 18650 builds. You still have to respect the fundamentals — cell orientation, BMS order, full insulation — but the kit removes the two hardest tools (the welder and the soldering iron), makes every connection inspectable, and lets you service the pack for years. It is not the cheapest route per cell and it is not for mass production, but for a bike, a chair, or a solar project that you want to maintain yourself, that trade is the right one for most people.

If you would rather buy a professionally built pack than assemble your own, custom e-bike and wheelchair batteries are exactly what we make. Dajiu Energy is a Chinese manufacturer building LiFePO4 batteries for RVs, homes, golf carts and portable applications since 2017. Our product range covers LiFePO4 drop-in replacement batteries, EV and golf cart batteries, wall-mounted home storage, portable power stations, commercial energy storage and battery swap cabinets — explore the full lineup in our product center, or browse more buying guides. If you do build your own pack, we’d still suggest matching the video’s care — and if you’d rather not, tell us your voltage, capacity and cell format and we’ll engineer the pack for you.

What Viewers Are Asking (Top Comments on the Video)

These are the most useful of the video’s top comments, with our practical answers. The original creator did not reply to these threads, so the answers below are ours — written the way we’d answer a customer on the shop floor. Thanks-only comments were left out on purpose; these are the ones with actual information in them.

@kjevers1 · 17 likes
"That would make a nice backup battery for my e-bike."
Our take: That is a perfect use case. A 36V backup for an e-bike is exactly what the video builds, and the solderless kit makes the maintenance story better than a welded pack: when one cell ages out, you open the caps, swap that cell, and keep riding — no re-welding, no spot welder. Just match the BMS and the charger voltage to your bike, and keep the pack fully insulated before it goes in the frame.
@itutetuh · 15 likes
"When it comes time to rebuild my battery from my ebike, I will be using this! Thanks."
Our take: Rebuilding an existing e-bike battery is precisely where this kit shines. The 36V 10Ah layout in the video is the standard e-bike form factor, so you can usually reuse the same cell count and BMS. Two tips from the build apply directly: lay every cap in the same orientation before seating cells, and wire the 10S BMS strictly in balance order — those two checks prevent almost every failure a first-time rebuild hits.
@jetenginethrust863 · 14 likes
"Cool, this is just what I'm going to need to build my hotrod powerchair. Needs to be 24V high amps and large capacity/Ah rating, probably a 100Ah battery pack. Thanks for sharing."
Our take: A powerchair pack is a strong fit, and your numbers point the right way. 24V means 7S (7 cells in series), and for the amp draw of a powerchair motor you want generous parallel strings — the video's 3P uses LG MJ1 cells, and for higher current you can step to a cell like the Samsung 25R or LG HG2 that handles more amps per cell. The barrel bolts are a real advantage here: powerchairs see constant vibration, and continuous compression is exactly what keeps the contacts tight.
@moonwalker573 · 12 likes
"As always, another nice demonstration. Thanks, Micah. This is an excellent example: when you have used batteries and some of them fail, you can replace only those affected cells, not tear apart the whole pack. Exactly what I need."
Our take: That is the killer feature of a solderless kit, and the video's whole design is built around it. A welded pack with one dead cell usually means cutting the nickel strip and re-welding — or replacing the whole block. With V2.1 you open the caps on that cell, swap it, re-torque the barrel bolts and go. For a pack you plan to run for years, that serviceability quietly pays for the kit.
@hallkbrdz · 11 likes
"I like this connection system, although I'd recommend using blue Loctite on the barrel bolts if they are used in a high vibration environment."
Our take: Worth being careful about. In the video's own comments, a viewer asked exactly this and the creator advised against thread-locker: the barrel bolts are doing double duty — holding the stack together and pressing the caps onto the cells — and a liquid thread-locker can wick into the contact area and interfere with the electrical connection. If you are worried about vibration loosening, the better habit is what the kit already gives you: check the barrel bolts for firmness when you service the pack, and keep the compression even.
@IdowuAsumah · 11 likes
"Now I'm definitely going ahead with my e-gokart build. Shout out from Lagos, Nigeria."
Our take: An e-gokart is a great project, and the 36V pack from the video scales well for it. Go-karts draw a lot of peak current, so consider cells rated for higher continuous amps than the MJ1, and add generous parallel strings — then follow the build's insulation step (Kapton, foam, full heat shrink) religiously, because a go-kart shakes more than a bike. The barrel bolts are a genuine plus for that environment.
@jamminjaymn7675 · 10 likes
"You did it! I've been wanting to buy these but was worried about the rattling while riding a custom ebike. The barrel bolts are exactly what I needed. Keep up the good work!"
Our take: That exact worry — rattling contacts on a custom ebike — is the reason V2.1 added barrel bolts, and the design change works: continuous compression across the whole stack replaces the old per-cap pressure, so the contacts stay tight under vibration instead of working loose. Combined with foam between cells to damp the shake, a V2.1 pack is built for a bike frame. Keep the bolts firm, not cranked, and check them when you service the pack.
@jtclendenin · 6 likes
"This is my fourth kit (V2 and V2.1). For sure buy 2.1. Life will be a bit easier. Also, there is a reason he is wearing gloves - that well-made plastic can be a pain, especially if you don't follow the instructions and need a do-over!"
Our take: Four kits in is a strong endorsement, and the glove tip is one of those details that saves real frustration. The caps are engineered plastic with tight tolerances, and when a cap sticks, bare fingers slip and make it worse — gloves give you the grip to seat them cleanly, especially on a do-over. And yes, V2.1 over V2.0: the easier-seating caps and barrel bolts are exactly the two things long-term users asked for.
@glock35ipsc · 5 likes
"I used this kit to put together a 14.4V, 10.2Ah battery pack for portable ham radio operations. First time out, the radio was used at 50-75 Watts output for right at 5 hours, and still had plenty of battery power in reserve. Outstanding kit!"
Our take: That is a genuinely useful real-world data point. 14.4V means 4S (4 cells in series), 10.2Ah from three parallel MJ1 strings, and a 5-hour continuous radio session at 50–75W — that runtime is exactly what the capacity math predicts, and the solderless connections held up under the radio's vibration. Portable field gear is a great use case: when a cell ages out, you swap it in minutes instead of rebuilding a welded pack.
@thomasjaszewski64 · 5 likes
"I've followed and have used all versions. While the earliest versions had limitations, they still serve my needs. V1 24V packs have been powering yard lights and charged by solar panel since they became available. The newest version seems the result of real listening."
Our take: Years of solar-charged service on a V1 pack is the durability answer the video's skeptics need. The kit has improved with every version — V2.1's barrel bolts and easier caps are the direct result of listening to users like you — and your experience is the pattern worth copying: build once, charge by solar, and repair by swapping single cells instead of retiring the whole pack.

Source video: EbikeSchool.com — “New & improved Vruzend V2.1 no-weld 18650 kit” (youtube.com/watch?v=rylbFnTgFI8). Comment excerpts are quoted verbatim from the video’s top comments; creator replies are quoted where they exist, and unanswered threads carry Dajiu Energy’s own answers. 570K+ views. A 36V 10Ah e-bike pack built entirely without welding using the Vruzend V2.1 solderless kit — 10S3P layout, barrel bolts, figure-8 bus bars and BMS wiring.