A fully off-grid power system constructed from over 650 salvaged laptop batteries has provided uninterrupted electricity to a private home in Farmingdale, New York, since 2016. Built without institutional support or commercial hardware, the project demonstrates a viable model for long-term, low-cost energy storage using repurposed lithium-ion cells and a solar array.
The system continues to operate with zero cell replacements or battery failures after nearly a decade—an outcome that challenges prevailing assumptions about lithium-ion degradation, battery safety, and the practical limits of e-waste reuse.
At a time when lithium supply constraints, battery cost inflation, and grid reliability dominate energy policy discussions, this project offers a functioning counterexample: a decentralized, durable, and cost-contained solution powered entirely by discarded electronics and consumer-grade solar equipment.
engineered from scrap, built for resilience
The system’s core is made up of 18650 lithium-ion cells extracted from used laptop batteries. The builder, known online as Glubux, disassembled each battery pack manually, tested individual cells, and arranged them into modular 100 Ah battery packs. Each pack contained between 51 and 80 matched cells, depending on capacity.
Construction emphasized electrical reliability. All battery packs were wired with 1.5 mm copper conductors, selected for their high conductivity and ease of soldering. Consistent bus bar lengths were maintained to ensure equal resistance and current distribution across all cells. The entire array is housed in a dedicated garden shed roughly 50 meters from the main residence.
To charge the packs, the system uses 24 rooftop solar panels, each rated at 440 W, yielding a total photovoltaic input of over 10.5 kW. Energy flows through a Victron MPPT 100/50 charge controller, a 3 kVA Victron inverter, and a 24V-to-12V voltage converter, powering the home directly without connection to the municipal grid.
Unlike most DIY setups, this one has shown no thermal incidents, fires, or swelling over nine years of daily cycling—an outcome attributed to cautious pack design, consistent voltage balancing, and conservative depth-of-discharge thresholds.
solving voltage imbalance through pack optimization
Early testing revealed discharge inconsistencies across differently sized packs. During one overnight load test—when powering two refrigerators and background loads—the system exhibited an unexpected voltage drop. Some packs remained at 3.3 V, while others dipped below 2 V, risking long-term damage to the cells.
Root cause analysis traced the failure to pack size imbalance. Smaller packs with fewer cells reached cutoff voltage faster than larger ones under equivalent current draw. The issue was resolved by adding cells to underperforming packs and rebalancing the entire system—an adjustment that stabilized energy retention and prevented premature voltage collapse.
Further observation revealed that cell voltage divergence was negligible when packs remained between 3.3 V and 3.8 V, but diverged more rapidly near full or empty states. To preserve long-term stability, the operator avoided extreme voltage conditions, staying within a mid-range charge window that reduced stress on the cells.
Performance tests under moderate and heavy load (e.g. vacuum cleaner operation at ~1,200 W) showed no signs of thermal stress or voltage instability, further validating the system’s structural design and load-handling capability.
no commercial support, no public funding, no grid reliance
The system operates without formal certification, government incentive, or connection to the regional utility. It remains 100% off-grid, relying solely on solar energy and battery reserves for year-round operation.
Operational costs have remained negligible. The original battery packs, assembled in 2016, are still in service. No cell replacements have been reported. Upgrades were limited to solar panel additions and minor hardware improvements. The builder regularly shares technical updates and performance logs on Second Life Storage, a community forum for DIY battery projects.
This stands in contrast to most residential storage solutions, such as Tesla’s Powerwall or LG’s Resu, which rely on new lithium stock and require professional installation. DIY projects using second-life cells remain outside regulatory frameworks in many jurisdictions and are typically excluded from home insurance policies and net-metering agreements.
