Disclaimers, license & safety

Plain-English reading of what the Wattplot project is, isn't, and what you take on if you build one. Read this before you build anything that connects to mains voltage or stores energy in a battery.

1 · What "open source" means here

The Wattplot project — firmware, schematics, PCB design, 3D models, documentation, and this website — is released as open source. That means the source files are public, the design is reproducible, and you can read, modify, and redistribute them.

What you can do with it

Read every line of code and every wire on the schematic.
Build one for yourself, your family, your school, your community garden.
Modify it for your climate, your panel, your bed size.
Share your modifications with others (open-source the changes too if you can).
Manufacture and sell units, locally or beyond, under the terms below.

What "open source" does not mean

It does not mean anyone else is responsible if it breaks, burns, shocks, or underperforms.
It does not mean the design is certified to any electrical, structural, or safety standard.
It does not mean you can ignore local building codes, electrical codes, or HOA rules.
It does not mean the "Wattplot" name belongs to you (see §3 below).

2 · License (MIT)

The Wattplot firmware, hardware designs, and documentation are released under the MIT License. The full text is at github.com/mokahlo/wattplot/blob/master/LICENSE.

In short: you may use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the software, subject to the following condition: the above copyright notice and this permission notice shall be included in all copies or substantial portions of the software. The software is provided "as is", without warranty of any kind.

The MIT License applies to the code and design files. The "Wattplot" name and any associated marks are covered by §3 below — they are not part of the MIT grant.

3 · On the "Wattplot" name

Honest disclosure: the author is aware of a prior commercial use of the name "WattPlot" in the same general field (solar / renewable energy monitoring). The product is wattplot.com, a monitoring-software suite for OutBack Power systems, sold under license by Andrew Welch of Intallact (Canada) since 2006. That product uses the ^™ mark, which signals a common-law trademark claim even if a USPTO registration has not been issued.

Common-law trademark rights arise from use in commerce, not from registration. Because WattPlot.com has been operating in a closely-adjacent space (Class 9 software for renewable energy, possibly Class 42 SaaS) for nearly twenty years, they have a reasonable claim to the name in those classes, in the markets where they've sold. This project (a physical solar-canopy planter with an ESP32 controller) is a different kind of product, but consumers may associate the two — which is exactly when trademark conflict is most likely to be asserted.

What "not selling it" actually means

The MIT License above permits anyone (including you) to build and sell units. If a third party — or you, later — sells a unit branded "Wattplot", that is commercial use. Open-source ≠ non-commercial. Hobby use with no sales is the lowest-risk posture, but it's not a legal shield.

The author's position (and the four real options)

The author has chosen to keep the project name "Wattplot" for now, for these reasons:

Different product class (physical planter + actuator controller, not monitoring software).
No commercial sales by the maintainer.
Project is clearly identified as an independent open-source effort at mokahlo/wattplot.

You — as a builder, modifier, or potential seller — should make your own informed call. The realistic options are:

Keep the name, accept the risk. Hobby / non-commercial use is very unlikely to attract a cease-and-desist. Commercial resale of units branded "Wattplot" carries a non-zero risk of a C&D from the WattPlot.com holder, especially if any units are sold in the same channels they operate in. Defensive disclaimer (this page) is not a legal defense, just evidence of good faith.
Rename before you scale. If you plan to sell, distribute at scale, or trademark the name yourself, picking a different name now is essentially free and removes the risk entirely. The project is new enough that a rename is a one-day PR (name, logo, repo, docs).
Reach out for a coexistence agreement. Email Andrew Welch at wattplot.com and ask if he'd be comfortable with the coexistence. "Wattplot" the planter, "WattPlot" the monitor, two different products, two different websites. This is the most legally-clean path if you want to keep the name.
Re-brand as derivative. Keep the name internally, but market externally as "open-source solar planter (based on the Wattplot design)" or pick a product name like "Sunbed" / "Solataire" / "Plotsol" for the unit you actually sell.

Verification you can do yourself

US: search USPTO TESS for "Wattplot" and "WattPlot" in Class 9 (solar software), Class 11 (solar lighting / apparatus), Class 42 (software as a service).
Canada: CIPO Canadian Trademarks Database — same search terms.
EU: EUIPO eSearch.
WIPO global: WIPO IP Portal.
This is not legal advice. If you plan to sell, talk to an IP attorney in your jurisdiction. A 30-minute consultation ($150-$400) is cheaper than renaming a product line later.

What the maintainer is doing about it

The maintainer has prepared two internal strategy documents (not linked from the public site — see the project repo if you want to read them):

A draft coexistence request to Andrew Welch, sent through the public support channel — the goal is to confirm he's comfortable with two distinct products sharing the name in clearly different markets.
A rename execution plan (Plan B) — a one-session, ~4-hour migration to a new project name if coexistence is declined. The plan preserves logo, repo history, GitHub redirects, and external links.

The decision will be reflected here once a reply is received. If the project is renamed, this section will be updated to credit Andrew Welch and explain the history.

4 · Waiver of liability

By building, operating, or distributing any device based on the Wattplot designs, you acknowledge and agree that:

You assume all risk. Solar panels, batteries, and mains-connected equipment can cause property damage, fire, serious injury, or death.
You are responsible for safety. You are solely responsible for verifying that your build complies with local electrical codes, building codes, and product-safety standards in your jurisdiction.
You waive claims against the maintainer and contributors of this project, to the maximum extent permitted by law, for any injury, loss, or damage arising from your use of the designs.
You are not relying on the maintainer for safety advice. The maintainer is sharing designs as a hobby and an act of generosity — not as a licensed electrical engineer (unless explicitly stated in a specific commit's author metadata).

For a mains-connected or large-scale commercial build, hire a licensed electrician. The cost of professional review is trivial compared to the cost of a house fire.

5 · Electrical-system danger — read this twice

A solar canopy on a raised bed is a real electrical system, not a weekend toy. Treat every wire, every terminal, and every battery cell as if it can kill you, because it can.

Specific hazards in this build

Solar panels generate voltage whenever light hits them. You cannot turn them off. Cover them with an opaque tarp before touching the back of the panel or its wiring.
Lithium (LiFePO4) batteries store enough energy to deliver a fatal current through a ring of steel, or to start a fire if shorted, overcharged, punctured, or heated. Never work on a battery with jewelry on your hands.
12 V DC at high current can weld metal, melt insulation, and start fires just as readily as mains AC. A 100 Ah LiFePO4 bank can push 500+ A through a low-resistance short — enough to set a wrench on fire.
The DRV8871 H-bridge used in the actuator path can fail short, applying full battery voltage to a stalled motor — the motor can overheat and ignite its housing within minutes.
Wind can move a 35°-tilted panel with enough force to injure a hand or a back. Lock or remove the panel before maintenance in any wind.

Non-negotiable safety practices

Disconnect the battery AND cover the panel with an opaque tarp before doing any wiring work. Both. Always.
Install an appropriately rated fuse or DC breaker within 6 inches of every battery terminal.
Use wire gauge rated for the actual current — undersized wire is a fire starter.
Use a charge controller matched to your panel and battery chemistry. Do not bypass it. The schematic uses a Sunapex 10A MPPT for the mini build; the full-size 620W build needs a Victron SmartSolar 100/30 (or EPEver Tracer 4210AN) — sized for the panel's Imp (~17 A), not just Voc.
If a battery is ever hot, swollen, or venting — evacuate the area and call your local fire department. LiFePO4 venting is less dramatic than LiPo, but the off-gas is flammable and toxic.
Have a Class ABC fire extinguisher within reach when working on any battery system.

This is not an exhaustive list. Local electrical codes (NEC in the US, IEC in the EU, AS/NZS in Australia/NZ) take precedence over anything in this project. When in doubt, hire a licensed electrician.

6 · No warranty

To the maximum extent permitted by applicable law, the Wattplot designs, code, and documentation are provided "as is" and "as available", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose, and noninfringement.

The maintainer does not warrant that the designs will meet your requirements, that operation will be uninterrupted or error-free, or that defects will be corrected. The entire risk as to the quality and performance of the designs is with you.

Some jurisdictions do not allow the exclusion of certain warranties; in those jurisdictions, the above exclusions apply to the maximum extent permitted, and the remaining provisions remain in effect.

Last updated: 2026-08-05 · maintained at github.com/mokahlo/wattplot/blob/master/docs/disclaimers.html · open a PR if you want to propose a change.