Build Your Own Battery.
From Hardware Store Materials.
An all-iron flow battery that stores energy in liquid electrolyte. No lithium. No fire risk. No monthly payment. Made from scrap iron, table salt, and a trip to Home Depot.
Every kit includes The Complete Build Guide free — detailed instructions, wiring diagrams, and pro tips.
Get the 5-Minute DIY Battery Blueprint
The entire concept explained in 5 minutes. How it works, what it costs, and why iron beats lithium for off-grid storage. Free. No spam. Just one builder talking to another.
Why I'm Building This
I'm Brandon Reed. I ran a mobile touch-up business for years — the kind where you drive to dealerships and fix paint chips out of the back of your truck. I built my own operations software from scratch because nothing on the market understood how this work actually flows. I solve problems by building things.
I've got dreams of setting up a homestead in Tennessee — somewhere my wife and kids can spread out and we can live off grid. The first thing I needed to figure out was power storage. Solar panels are cheap — but batteries? A lithium system big enough for a family costs $10,000-15,000 and needs replacing in 10 years. That's a car payment for a decade. I don't do payments.
So I started digging into flow batteries — they store energy in liquid, not solid electrodes. Want more runtime? Bigger tanks. Want more watts? More cells. The electrolyte never wears out. But commercial flow batteries use vanadium ($150/liter) and Nafion membranes ($500/m²). Way out of reach for a homesteader.
Then I found Rowow's open-source membrane technique — ground water softener beads + PVC cement. $0.10 per cell instead of $500. I figured out the electrode: cornstarch + Elmer's glue + PVC cement, torched with a propane torch. It puffs into carbon foam — like popcorn. The electrode grows directly on the membrane.
The whole thing costs about $150 in materials from Home Depot and Amazon. Everything is on GitHub. I just don't want a power bill — and I figured other people don't either.
Straight Talk
You've got questions. Good — you should. Here's what you need to know.
Does this actually work?
Iron flow batteries are proven chemistry. ESS Inc. ships commercial units to utilities right now. The difference is we're building them from hardware store materials instead of specialty lab equipment. Same reactions, same physics — different price tag.
Why are the materials so cheap?
Because we cut out the expensive parts. Commercial flow batteries use vanadium ($150/liter) and Nafion membranes ($500/m²). We use scrap iron, water softener beads, and PVC cement. The chemistry doesn't care where the materials came from.
Why give everything away for free?
Because the whole point is getting this technology into people's hands. Every build file, every recipe, every design is on GitHub. You don't have to buy anything from us — the kits just save you the prep time. We'd rather have 10,000 people building than 10 people paying.
Why isn't everyone doing this already?
They're starting to. Rowow published his membrane technique. FBRC is building open-source designs. We're just the first ones putting it in a kit and filming the whole build. This space is about two years away from being everywhere.
Is it safe to build at home?
The electrolyte is water-based acid — about pH 1-2, similar to lemon juice concentrate. Wear gloves and goggles. Zero fire risk — you physically cannot get a thermal runaway from iron dissolved in water. Ventilate when using PVC cement (same as any plumbing project).
How much power does it actually make?
Based on the chemistry and cell dimensions, we estimate each 50mm test cell at ~1.2V and ~1.25W. A 4-cell stack: ~4.8V, ~5W — theoretically enough to power its own pump and charge a phone from solar. Scale to 300mm cells for an estimated ~49W each. We're still testing and documenting real-world numbers on YouTube.
Choose Your Kit
Everything is open source — build it yourself from the free GitHub docs. Or grab a kit and skip the prep work. Either way, you're building a battery.
Materials Kit
Everything to build your first membranes and electrodes
- Pre-separated cation resin beads (ready to grind)
- Activated charcoal pellets for cavity fill
- Non-woven landscape fabric (cut to size)
- PVC cement (clear, 8oz)
- Cornstarch + Elmer's glue for popcorn ball electrodes
- Printed quick-reference build card
Pre-made MEA
Cast, torched, and ready to install
- 50mm active area (25 cm²)
- Popcorn ball electrodes with triple porosity
- Soot-blackened SS screen current collectors
- Landscape fabric overhang for gasket seal
- Ready to PVC cement into your cell box
Assembled Cell
Complete cell — just add electrolyte
- 3D-printed ASA box (VzBot 400)
- Interior walls coated with popcorn ball electrode
- Activated charcoal cavity fill
- Sealed-zone terminal screws installed
- MEA bonded and cured
- Vinyl tubing ports ready to connect
Electrolyte Concentrate
FeCl₂ in HCl — ready to pour
- 1 gallon concentrate (~1M FeCl₂)
- pH 1-2, pale green color
- Enough for 4-cell demo + reserves
- Ships ground only (hazmat)
- HDPE container included
Complete Starter Kit
Everything. One box. Build a working battery.
- 4 fully assembled 50mm cells
- 1 gallon electrolyte concentrate
- Pre-cut vinyl tubing + manifold parts
- Micro peristaltic pump (3-5V)
- DC-DC boost converter (5V USB output)
- Wiring harness with terminal screws
- Printed step-by-step build guide
- Access to build video library