DIY 18650-cell battery-pack building KITS, five options for 2018

June 21, 2017

Recently, we have seen several kits for assembling a battery pack out of 18650 cells. Here are some examples, so you can see if that is something that might interest you. And remember, these aren’t just for ebikes, you can assemble any voltage or size you want, for any job you need a battery to power.


The Headway company makes cylindrical cells that use the Lithium-Iron-Phosphate chemistry (LiFePO4), which provides 3.2V per cell nominal. The other thing they are famous for is that their cells come from the factory with threaded studs on both ends of the cell. Also, their website provides all the parts to assemble a pack…including pre-cut metal bus-plates, and square plastic end-caps. I don’t know when they started this, but I wrote an article about a build that used these back in 2013, so this example of assembling a pack has been around since then, at the very least.

Headway pack building kit

海德威包建包。示出的模块是8S / 2P

Since this is clearly awesome (because you don’t have to solder or buy a spot-welder), then…why aren’t they more common?

Headway cells don’t come in a variety of sizes (there are only two), and the smallest one is the 38140. This means that they are 38mm in diameter and 120mm long…and that, my friend?…that is BIG. The 38120 cell is 10-Ah for one cell, so a 2P pack would be 20-Ah. Although 20-Ah is a good size of pack (that I very much approve of), the only shapes you can configure them in is usually a big fat rectangle.

To give you an idea about how large the “small” Headway cells are, here is a reproduction of a vintage boardtracker from Juicer ebikes. The Headway cells are the blue cylinders that make up the V-twin cylinders.

我们的朋友teklektik建立一个浴霸世界报长尾cargobike早在2012年,这些细胞,再加上“Juicer” board tracker ebikes have used the 38120,and also, here isa pic of a pack that was assembled to replace a 24V lead-acid pack on an electric wheelchair

Micah Toll’s pack-building kickstarter

We were excited to write about Micah’s kickstarter campaign. He realized that there were a lot of battery pack builders who didn’t want to buy a spot welder (commonly $300 or more for a very basic unit), but many of the home-builders were comfortable making the series connections with a fat wire and a soldering iron.

Micah Toll’s DIY battery pack building kit



Damien Rene pack-building spot-weld article

达米恩刘若英是在西班牙的电动自行车发烧友。我们的一个最一贯流行的文章是关于如何在一个he builds spot-welded battery packs for ebikes, found here。话虽这么说,最基本的点焊单元则可以从中国直接购买是SUNKKO 709A,它可以为大约$ 300在2017年被发现,即使为“合格”为模式,你可以在google搜索“SUNKKO失败”,并找到如何修复讨论线程和升级设备上的胆量。


有18650细胞点焊模型比SUNKKO 709A更强大和可靠的,但是......他们的成本也超过$ 300。


For a very long time, there has existed a plastic end-cap design that helps the pack-builder to assemble a pack. The “slot” on top of the cells is an 8mm wide alley, which is often filled with a 7mm wide ribbon of pure nickel (nickel bus-ribbon that is o.15mm or 0.20mm thick are the most common).

因为我发现,当我正在研究的18650格式的单元结构的文章,认为双方每18650细胞的底部是一个连续的导体(即:侧面和电池的底是带负电荷的)。这意味着…these plastic end-caps are very important。Vibration over the years can break through the PVC insulation-sleeve that comes over the sides of the cells, and a break right there will allow a short-circuit near the positive end.

积极的肩膀阴极附近的区域of the cell is the “danger zone”, and a compromise there is something that I call a “shoulder short” (the end with the white ring, in the pic below). It is VERY beneficial to add a self-adhesive fiber insulation washer to the positive end, and to use some type of plastic end-cap.


The common style of plastic end-cap

一旦你决定塑料端盖的可用模型,你怎么连接串联和并联每个单元?下面的PIC是一个共同的2S / 4P总线板。在该PIC,在镍母板上的四个垂直通路携带高系列电流。如果这些是10A细胞,然后四个垂直运行中的每一个进行,每10A,总共40A的整个包。

两个水平的途径携带并联电流,这仅因为它们充放电保持单元以相等的电压。它通常将小于图1A中,即使对于非常高功率的电池组。的唯一原因串联和并联通路具有相同的宽度和厚度上总线板的这种共同的风格,是... ...这样做使得快速和容易的激光切割的形状,并且所述镍是刚性的,足以增加一些结构刚性所得到的包。

To be clear, if you are charging your pack with a 5A charger, that 5-Amps is charging “in series” too, so…the parallel connections will only carry a tiny amount of balancing current, under all charging and discharging conditions.


A 2S /4P battery pack series / parallel bus-plate. The top row of cells have their positive ends up, and the bottom row of four has the negative ends up…Remember! the entire sides of all 18650 cells are charged with the negative end. That is why battery pack builders add the dark gray felt washers to the positive ends! (seen on the top row). The slot above each cell helps the spot-welding to be more consistent at a lower energy level. If the current can simply pass across the nickel strip, very little energy passes through the cell-end to weld them to the nickel bus, so it takes much higher energy levels, and results in much more heat than necessary.

事实上,镍是不是一个伟大的指挥家。它仅用于两个主要原因。I ‘would’ state that it has very strong anti-corrosion characteristics, but…nickel-plating over copper bus-plates [or aluminum] has the same corrosion protection, and that composition would conduct better and costs less (nickel is expensive, and getting pricier each year). The first reason is that…pure nickel is stiff, and provides some structural strength, while copper or aluminum is malleable (soft and easily bendable).

The second reason is that pure nickel [as a bus material] will spot-weld quite easily and very fast, which helps the assembly-line move along rapidly. Although many packs are still spot-welded in China one cell at a time by a person, the trend is to have robots spot-weld a pack together very rapidly.


Personally, I am a fan of the “honeycomb” configuration, over the now common rectangular “rank and file” shape (shown above). For roughly the same volume of battery pack, the honeycomb layout provides more air-flow between each cell. Whether you are trusting in passive heat-shedding, or a pro-active fan-cooling system…if you have a more consistent air-flow envelope around each cell? It will help each cell to shed any of the heat that develops.


The endless-sphere forum member “Agniusm” is a very smart enthusiast from Lithuania. I am posting his “NESE” modules first because…the 6P modules have been tested at 80A (13A per cell), and the bus-strips only warmed to 30C / 86F.


This business model recognizes that any new clever design can be copied and produced very cheaply in China, so…rather than create the modules himself and ship them around the world…he provides the design code for free, so each builder can have them produced locally from a 3D printer service. The difficult part that he does provide for the customers is…the metal 6P bus-plates, which can be trimmed-down to fit in any of the other sizes of case, along with the Poron foam backing (6P, 5P, 4P, 3P, 2P, etc).

The size of the module is determined by the design file used to 3D-print it up, and the color is determined by the plastic filament used on the 3D printer.





Here are two 4P modules configured as an 8P group. The black “zip tie” shown is an easy and affordable way to attach several modules together.

这里是一个PIC(下图),示出了“横向”组件,这PIC示出了“10个模块系列”(10S)包,其通常被认为是36V。如果您使用这些6P模块与3500毫安细胞,示出将是(6×3.5 =)21-阿包。

Beneath the orange 3D-printed protective insulating caps, these modules shown below are connected positive-to-negative in order to “series” them into the desired voltage. Do your home work, and exercise caution!

使用这些3D印刷塑料模块当一个10S / 6P包的例子。


下面是这些模块中的一个纵向取向的例子。示出的包是16S / 6P



The Vruzend kit adds plastic cell-end caps to each end of a cell, and each cap has a metal contact inside, along with a tiny bolt that extends out to create a threaded stud for attaching bus strips.

The standard Vruzend plastic end-cap set from India.



The pic below shows one Vruzend cap cut open, and the metal contact has been removed to show its exact shape. It is a “corrosion-resistant” stainless steel, and it acts as a “leaf spring” that has a “C” shape. It also performs the duty of being the conductor, so these are limited to 3.5A each. A future version may have a copper foil overlay to provide a higher-amp version, but those are not available yet.

The basic model of Vruzend cell end-cap.


一个简单的7S / 3P包,通过使用Vruzend端盖系统制成。

The original kit was based out of India, and now…there is now a US-based dealer in Florida…which is managed by Micah Toll.

I thoroughly approve of two colors being used for the end-caps. I would have preferred using black for the negative ends (instead of blue), but…RED is ALWAYS the positive. If you do not use red for the positive, you should be dragged outside and whipped with a handful of wet spaghetti noodles.


If you wish to experiment with a copper foil overlay to increase the safe amp-carrying capabilities of these contactors, I recommend that your initial experiments use 0.25mm thick copper foil (also called, 10-mil, or 30-ga)



I bought one box of these to test, and I am impressed. They are similar to other kits, but there are two differences that interested me. First, the electrical contact and the spring that holds the contact against the cell-end are two separate elements. This means the spring can be made from a material that is perfect for a long term application of tension.


Second, since the spring and contact are two different materials, the contact can be made from copper (and pure copper is a great conductor, but a horrible material for a spring). The Nishi contacts are zinc-plated for corrosion protection, and I have sanded the plating off of several samples to verify that the contacts are indeed copper. The width and thickness of the strip has the same cross-section as 13-ga copper wire, so it can handle temporary occasional current peaks of 15A, which means it will work for my favorite ebike cell, the Samsung 30Q.

The fully assembled 18650 cell and Nishi end-caps are 75.5mm / 3-inches tall.

The materials shown off to the left in the pic above are 1/4-inch plywood, and 1/4-inch HDPE kitchen cutting board. Either one would make good side-panels to hold and protect a pack made from the Nishi pack-building system. These caps also connect side-by-side using splines on their sides that interlock.

Battery Blocs

“电池集团”的广告似乎表明,他们觉得他们最好的客户群是DIY“特斯拉墙”领域的不断扩大。我的意思是......如果你有经济实惠的18650个细胞的来源,你可以组装一个巨大的电池组在你的车库墙上,以便安装,并且它可以从一个被充电)的太阳能电池板,而你是在工作,还是...... B)您可以使用“电墙”作为备份,因为你住的地方电网是不可靠的,而且......你把它从电网充电......而你在半夜充电,当成本较低。

四12P子组配置为4S / 12P电池组。



The most noteworthy feature of this kit is that…they use asmall-but-strongneodymium “button” magnet as the connector to each cell-end. These magnets are mostly composed of steel, so…they are not good for high amps. This is not any issue for a very large “low-amps-per-cell” Power Walls. However, if you want to use these for the battery of a a longtail cargobike, upgrading the amp-capacity of the connections may involve adding a copper foil ribbon in-between the magnet and cell-tips (for initial experiments, you might consider using 0.25mm thick, 10-mil / 30-ga copper sheet).

Battery Bloc kits are available in a variety of configurations (4P, 6P, 8P, etc), so take your time shopping to see if these would work for you.You can find their website by clicking on the link, here


The Energus company makes modules very similar to the NESE modules at the top of this article. However, they prefer to produce complete modules, which already have the cells inserted. As such, you must specify which cell you want inside the module (max amps, max range…or something in-between). and they also have a “plug and play” wiring harness available for the BMS, if you want.



如果你喜欢这些,their website can be found, here

Ann Power

A reader sent me this link to “Ann Power” in China. The Chinese “ebay” is called Aliexpress. Sometimes you can get a good deal on there, and sometimes you get ripped off, but…it exists.

The brass threaded insert seen below only holds the nickel bus-plate onto all the cells in that group while you are spot-welding them, and then the bolts hold a copper sheet over the nickel to help increase the conductivity and lower current resistance.


The Ann Power battery pack building system



由Ron采写/ spinningmagnets,2017年6月

在加利福尼亚州洛杉矶,从1977年至1981年/美国圣迭戈海军潜艇机械师长大。在1980年的液压技工/洛杉矶。重型设备操作员在1990年/前往不同地点。自卸车司机在2000年代/ SW犹他州。目前,由于2010 / NW堪萨斯州水厂运营商


  1. Love the information

  2. 你也三维模从图瓦(法国产品)试剂盒。

  3. “事实上,镍是不是一个伟大的指挥家”嗯,你的意思是,在未来的日期和时间的时候,我们发现超导体,或2017年至今,其中镍是地球上最好的电导体中的一个,其实更好than copper, which itself is key to all the world’s electronics? Can you explain that statement please???

    • 感谢您的答复。尼克尔斯IACS电导率大致22/100相比铜板100/100。使用铜作为总线材料的问题是,铜容易被氧化(产生棕色涂层,该涂层的电阻),这是不好的压力触点。此外,它是非常困难的点焊到18650电池的电池的端部,这是典型的镀镍钢。

      铜是这样一个伟大的指挥家,它不get very hot when you pass spot-welding current through it. The resistance of nickel is why it gets hot so easily with a spot-welder. Nickel must reach roughly 2600F in a tiny spot to melt onto the cell-end, and it must do that very fast before any heat can migrate down into the cell.



      Tesla uses a thick aluminum bus-plate, but their fuse-wires use a high-speed ultra-sonic vibration technique to bond the connections on the bus and the cell-ends. Also, they use so many cells (thousands per car) that they get very high pack-amps while only drawing low amps from each cell. They chose aluminum for the bus-plates because it was lighter and stiffer than copper.

      As to the cost of materials, copper is less expensive than nickel, but the plating process costs money, so…nickel-plated copper costs more than pure nickel (even though the volume of nickel-plating material is very small).

  4. Rank Metal
    3 gold
    4 aluminum
    6 nickel
    8 bronze
    9 tin
    10 platinum
    11 carbon steel
    13 stainless steel

  5. 谢谢for a great article!


    A guy there uses brass standoffs as contacts.

  6. 大Infor的,谢谢。所以,你知道任何修复在洛杉矶附近/电动自行车电池的?

  7. This is the best list I’ve seen so far for battery pack terminals/connectors, i hope it’s updated and expanded as time goes on!!! thanks Ron

  8. Any chance you could update the article – with a focus on individual cell fusing options. Seems that bonded fuse wires are the way Tesla and Luna are going. And when I looked at A123 prismatics a while back they had a fuse integral to the tab on each cell. I like the Vruzen approach but the user has to modify the design with his own bus structure to add cell fuses. Some say they aren’t required for ‘new’ match cells – but don’t they all become unmatached ‘old’ cells over time.
    For the hobbyist there has to be a ‘better’ option ???

  9. I see no way to order. I am looking for a parts list to order from.


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