Build Your Custom Battery with Gouach Battery Builder

Learn how to use the Gouach Battery Builder to design your next battery in minutes and get samples in under a month!

Open the Gouach Battery Builder

The Gouach Battery Builder allows anyone to specify and design a battery online in minutes, order production-quality samples (shipped in under a month), integrate and test them in your product, and order high-quality, mass-produced batteries in record-time!

How to use the Gouach Builder

Let’s first look at the interface of the Gouach Builder:

1. Top panel: Get a quick overview of your battery's main features and an estimate of the mass production cost.

2. Side Panel: Customize all components according to your needs.

3. Editor view: Define the battery outline (the shape that will contain the battery). See how many cells (green circles) you can fit in your battery. Optimize cell placement (you can increase or decrease the number of cells and they will automatically be fitted in the defined shape). You can also move and rotate the BMS (blue shape) to position it correctly. Visualize it in 3D (3D button at the top).

4. Get a Quote: Receive a firm quote from Gouach in under three business days by submitting your project using the “Get quote” button. You can also request a number of samples (shipped under a month). No credit card is needed at that stage, we will recontact you by email to review your project and ask you more details.

5. Export and Share: Export the battery in various formats, or get a shareable link that you can send to other members of your team, or bookmark to record your current design.

Get a Quote and Order Samples

Once your design is ready, use the "Get Quote" button for a firm quote in under 3 business days. This will allow us to review your design, and contact you with the exact pricing.

If you desire so, you can also ask us to provide you with production-quality battery samples, which will be shipped to you in under a month!

No credit-card is needed at this stage, we will first do a review of your project, and then contact you by email to get you started on producing samples and ordering batteries.

Define Your Battery

Use the side menu to define the characteristics of your battery: the cell chemistry and model, the BMS type, the requested voltage and energy of the battery, as well as multiple options.

🔋 You can check the “How to design a battery” tutorial to have a better understanding of how best to design your battery.

Cell settings

This lets you define the cell chemistry, format, and model (also whether to use new or cheaper and eco-friendly refurbished cells).

The Gouach builder lets you choose between the two most-used cell chemistries:

  • LFP (also known as LiFePO4) has less energy density but a longer lifetime. It is often used for energy storage systems or batteries where space and weight is less constrained.
  • NMC can fit more energy in less volume but will have a shorter lifetime in terms of charge-discharge cycles. Typically used inside e-bikes, automotive, or power-tools batteries.

⚠️ Note that the ageing of cells also depends on many other parameters (depth-of-discharge, usage temperature, etc).

You can then select the cell format (dimensions). As of now, we offer the two most used formats of cylindrical cells, 18650 (18mm x 65mm) and 21700 (21mm x 70mm).

For each chemistry and format, you will be able to select one of the corresponding cell models. The Gouach Builder gives you access to the cell price, its main characteristics, and a detailed data-sheet.

Battery settings

You can choose the battery layout (flat or stacked, coming soon), the battery voltage and energy, and the cell-placement constraints (minimal distance between cells, minimal distance between cells and the outline or the BMS).

BMS settings

You can choose the BMS which is most adapted to your use case.

⚠️ Some BMS have a limited capacity in terms of the number of cells in series that they allow. If your BMS does not allow for a given capacity, it will be automatically reduced.

For those BMS that allow it, you can optionally add an I/O module to your BMS (+$10) in order to let your user see the state of his battery (led display). It is possible to download a 3D model (.step file) of the I/O module to integrate it in your device.

The characteristics of the BMS are then displayed, in particular the MOSFET topology (low-side/high-side, common-port/split-port) which can affect the capacities and price of your BMS:

  • Low-side: cuts negative pole in case of error, cost-effective, requires isolated communication, suitable when battery communication isn't needed.

  • High-side: cuts positive pole in case of error, costlier, no isolated communication needed, simplifies design when battery communication is essential.

  • Split port: uses separate wires for charging and discharging, cost-effective, requires separate ports, suitable with a dedicated charge port.

  • Common port: same wire for charging and discharging, costlier, allows single port for both, suitable for bi-directional use-cases like solar charging.

When available, a precise data-sheet for the BMS can be downloaded.

How to Use the Editor

The editor pane enables you to shape your battery and position the BMS. Ensure optimal cell fitting by setting constraints and adjusting the battery outline.

1. The editor represents the battery outline (white path) containing the cells (green circles) and the BMS (green rectangle). The outline can be edited, and the BMS can be positioned, flipped and rotated.

2. At the top-left, there is an indicator giving the number of cells, and whether they all fit in the outline.

3. At the top-right, there are buttons allowing you to view the battery in 3d, to zoom on the battery, or to go in full-screen mode.

4. At the bottom-left, there are controls to flip the BMS in various directions in order to position it properly relative to the cells.

5. At the bottom-right, there are controls to edit the shape (create a box, move, add, edit or delete outline points).

Cell Fitting Constraints

The automated cell fitting respects a few constraints that you can modify: a minimal distance between cells and the battery outline, a minimal distance between cells and the BMS to avoid overheating.

There is also a “clearance space” around the BMS which must stay clear of cells, in order to have the space to attach cables. This space is represented as a white box next to the BMS. In the 3D view, this is displayed as a white wireframe next to the BMS.

Create the Battery Outline Shape

There are two ways of creating the outline shape.

One way is to use the “box” function (button at the bottom of the editor) to specify a rectangular shape of given width and height.

The other way is to add / delete point manually (using the “add” and “delete” buttons at the bottom of the editor), and drag them around to position them.

Note that you can force horizontal or vertical alignment by pressing the SHIFT key while dragging points around.

Clicking on a point will give you informations about the angles and distances between the points.

Finally, you can “edit” a point (by clicking on the “edit” button at the bottom and selecting a point, or by simply double-clicking on a point). This lets you define some constraints more precisely, like the angles and distances between successive points, or manually inputting the point coordinates.

Position the BMS

You can move the BMS by dragging it around, or rotate it by dragging the round handle which is attached to it. The white box attached to the BMS is the clearance space, which must stay clear of cells, in order to allow fitting the BMS cables.

In addition, you can “flip” the BMS along various axis to rotate it back and forth using the “Rotate BMS” controls at the bottom left of the editor. This might be more clear in the 3D view (see below).

View the Battery in 3D

You can view the battery in 3D by clicking on the “3D” button at the top-right of the editor. This allows you to view the battery as it will look like once produced.

You can download the battery 3D in multiple formats (more coming soon) by using the “Export” button at the top right of the Gouach Battery Builder interface.

1. The BMS is rendered using its own 3D model (when available) and the “clearance space” (which should be clear of cells to allow fitting the cables) represented as a white wireframe box.

2. The cell holders have an hexagonal shape and are packed together in a battery.

3. The PCB plates at the top and bottom (in blue) connect the cells together.

4. The white “clearance space" at the top and bottom of the model is extra space that you should make sure fits in your device, as it will contain extra material (plastic parts and screw heads).

Share and Export Your Project

The “Export” menu at the top-right of the Gouach Battery Builder interface provides multiple share and export options.

  • You can share an URL containing the data of your project with other people, or bookmark it to find your project later (if you send a quotation request using “Get quote”, you will receive an email containing a link to your battery so you can always find it later).

  • You can export the 3D model of your battery in various formats (more coming soon) to load them in your design software and fit them in your device.

👉 Learn more about Gouach battery design