Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

Original Article ↗ Hacker News Discussion ↗

What the Product Is and Main Use Cases

  • Seen as essentially a large, nicely designed, 120V LiFePO₄-based UPS with app control and optional solar input.
  • Intended for room‑ or appliance‑level backup: fridges, sump/well pumps (if 120V), networking gear, small electronics, and possibly furnaces rewired to plugs.
  • Not positioned as whole‑home backup; instead, multiple units per home or as a complement to existing whole‑home batteries or generators.
  • Strong interest from renters and people in apartments or older houses who can’t install Powerwalls or transfer switches.

Technical Capabilities and Limits

  • 1.6 kWh base unit, ~2.2–2.4 kW continuous output, large surge capacity for motor loads; expansion pack doubles capacity and solar input.
  • 120V only for now; many requests for 240V versions (HVAC, well pumps, kitchen appliances, non‑US markets).
  • ~20 ms transfer time draws mixed reactions: probably fine for appliances, borderline for some server gear.
  • Some debate over realistic fridge runtimes; marketing numbers (around 32 hours per fridge) are challenged using higher‑consumption examples.

Solar, Arbitrage, and Grid Interaction

  • Can charge from grid, rooftop solar (AC‑coupled timing), or directly connected PV (DC‑coupled, more practical in garages or long outages).
  • Supports time‑of‑use shifting and rate arbitrage, but many argue the small capacity makes financial payback weak; backup value is seen as primary.
  • Hardware is bidirectional: can backfeed through the outlet when the grid is up, where regulations allow (e.g., “balcony solar” style, Utah/EU examples).
  • Cannot island the whole home; during outages it only powers devices plugged into it.

Safety, Code, and Legality

  • Repeated concerns about backfeeding lines and lineman safety; replies emphasize an internal microgrid interconnect device (relay) that opens on outage to prevent unintended backfeed.
  • Some worry about large indoor lithium batteries and fire risk; supporters note LiFePO₄ chemistry and UL‑type certifications, but details are sparse in the thread.
  • Questions about US code compliance and wider allowance of plug‑in backfeed; currently fragmented and evolving.

Software, Networking, and Business Model Concerns

  • Local‑first design with MQTT, Home Assistant integration, and no internet required for core operation is widely praised.
  • Proprietary mesh between units is justified as more reliable than Wi‑Fi/Zigbee for coordination (storm mode, prioritization, shared data).
  • Strong suspicion from some that VC funding plus built‑in cellular implies a future virtual‑power‑plant and potential subscription/rug‑pull; founders counter with “no monthly fees” and a promise to open‑source schematics if the company fails.

Comparisons, Pricing, and Market Fit

  • At ~$999 preorder / $1299 list for 1.6 kWh, cost per kWh is seen as high versus DIY rack batteries, EcoFlow/Bluetti‑style power stations, or generators, but comparable to branded “solar generators”.
  • Supporters emphasize form factor (fits by appliances), low‑noise cooling, automatic standby behavior, and software integration as differentiators.
  • Critics view it as a polished, expensive UPS in an already crowded category, with marketing that over‑associates it with Powerwalls and whole‑home systems.