https://www.perplexity.ai/search/i-have-a-hybrid-vehicle-for-a-0K14jsEjT4ycJ8cCYZrvlA?sm=d
<img src="https://r2cdn.perplexity.ai/pplx-full-logo-primary-dark%402x.png"; style="height:64px;margin-right:32px"/> # i have a hybrid vehicle for a bit and it's fun to charge it but expensive when i drive around like a headless chicken on wheels. i was thinking, maybe i could make a huge solar panel (far bigger than the car) on the cheap that could give it at least 10 kWH in a day or two of full sunlight using approaches like: - soldering together cell shards in some augmented way like an xy table and jig (so it can be like a distracting project rather than a further financial sink) - using modern higher efficiency components - dynamically rerouting the cell network to maximize power - reangling to maintain high exposure - anything else that would help! How big would it have to be? Could it be made easy to build? I was thinking it could unfold on the roof to become enormous, or could be lifted into the sky with kites or balloons This is a fantastic project idea — right up your alley as a hacker who loves distracting builds. Here's the full breakdown for Oviedo, FL. ## How Big Does It Need to Be? Oviedo gets about **5 peak sun hours/day** on a fixed panel, rising to **6.1 hours** with single-axis tracking and **7.1 hours** with dual-axis tracking. Using that, here's what you need for **10 kWh in one day**:[^1_1] | Cell Type | Fixed Tilt | Single-Axis | Dual-Axis | | :-- | :-- | :-- | :-- | | Broken/B-grade poly (~15%) | **19 m² / ~14ft square** | 15.6 m² / ~13ft sq | 13.4 m² / ~12ft sq | | B-grade mono (~18%) | 15.9 m² / ~13ft sq | 13 m² / ~12ft sq | 11.2 m² / ~11ft sq | | New mono PERC (~21%) | 11.9 m² / ~11ft sq | 9.8 m² / ~10ft sq | 8.4 m² / ~9ft sq | | N-type TOPcon (~23%) | 10.9 m² / ~11ft sq | 8.9 m² / ~10ft sq | 7.7 m² / ~9ft sq | If you relax the target to **10 kWh in 2 days** (5 kWh/day), the area roughly halves — an 8ft × 8ft panel with B-grade mono cells on a single-axis tracker would do it. That's large but absolutely buildable. ## Building It from Cell Shards The DIY broken-cell approach is well-proven. People have built functional panels from grab bags of chipped/B-grade cells that cost as little as **\$0.08–0.10/watt** — one builder got 600W of broken cells for \$50. Used complete panels go for **\$0.10–0.15/watt** from places like SanTan Solar.[^1_2][^1_3] ### XY Jig Approach A tile-spacer jig on plywood works brilliantly for aligning irregular shards. Glue tile spacers in a grid pattern and the cells self-align, freeing you to focus on soldering rather than fiddling with placement. For an assembly-line feel:[^1_4] - Use **pre-tinned tabbing ribbon** (100ft for ~\$20 on eBay)[^1_5] - A **15–25W soldering iron** with rosin-core 60/40 solder[^1_5] - **Flux pen** — critical for clean joints, but verify it doesn't corrode cells long-term[^1_6] - Sort shards by approximate size and current output with a multimeter — cells in a series string must be matched by current (the weakest cell bottlenecks the whole string)[^1_5] - Wire glue is an alternative to soldering that makes broken-cell mosaics semi-rigid, at ~5% power loss[^1_7] ### Cost Estimate For a ~2 kW system from broken cells on a fixed mount: **~\$360–\$760 total** including cells, tabbing, encapsulation, MPPT controller, and frame materials. Buying bulk used panels instead lands around **\$400–\$660**. Either way, well under the cost of a commercial installation. ## Dynamic Cell Network Reconfiguration This is where your embedded skills shine. Research into **switching matrices** for PV arrays shows that dynamically reconfiguring series/parallel connections under partial shading can boost output by **up to 42–252%** versus fixed wiring, depending on shading severity. The approach:[^1_8][^1_9] - Build your cells into small sub-modules (e.g., groups of 8) - Use **MOSFET switches** or relays controlled by a microcontroller to reconnect groups between series and parallel configurations[^1_10] - An **MPPT algorithm** (perturb-and-observe or incremental conductance) running on an ESP32 can sweep the power curve and trigger reconfigurations in real-time[^1_11] - The deterministic reconfiguration algorithms have computation times around **0.001 seconds**, easily real-time even on modest hardware[^1_8] This is especially valuable for a broken-cell panel where individual cells have mismatched outputs — the switching matrix lets you route around weak cells or group similar-output cells together dynamically. ## Sun Tracking Single-axis tracking adds **~22% energy gain** (5.0 → 6.1 peak hours), and dual-axis adds **~42%** (5.0 → 7.1 hours) in Oviedo. DIY trackers are very buildable:[^1_1] - **Single-axis**: A linear actuator + two photoresistors + an Arduino compares light levels on each side and tilts until balanced. Boosts output 25% over fixed.[^1_12][^1_13] - **Dual-axis**: Four LDRs in quadrants, two actuators, same balancing logic. Keeps the panel perpendicular to the sun all day and across seasons.[^1_14][^1_15] - Both can be built from scrap materials — one builder made grid-tied dual-axis trackers entirely from repurposed parts[^1_16] ## The Wild Ideas: Unfolding Roof and Kites/Balloons ### Foldable Roof-Mounted Array This is genuinely practical. Military-grade foldable solar panels already exist that mount flexible cells onto weather-resistant fabric — PowerFilm makes a 220W panel that folds into a carry case at only 14 lbs. For a DIY version:[^1_17] - Mount cell sub-panels onto **hinged lightweight frames** (aluminum angle or fiberglass) that fold accordion-style - Store folded on the roof rack; unfold to 3–4× the car footprint when parked - Fabric-backed cells (like PowerFilm's design) are more resilient to flexing and partial damage[^1_18] A car roof is roughly 1.5 m², so unfolding to ~10 m² means about a **6–7× expansion ratio** — entirely achievable with accordion or fan-fold geometry. ### Kites and Balloons This is less far-fetched than it sounds. A French-Japanese lab (NextPV) has studied **balloon-mounted solar panels** above the cloud layer, where irradiance is up to **5× stronger** than at ground level and production is entirely predictable. Chinese and Swedish researchers have built working prototypes of **helium balloons with solar collectors** that send power down via tethered electrical cables. A WPI feasibility study on **solar kites at 8,000m** altitude found them cost-effective, producing ~154 kW in their design.[^1_19][^1_20][^1_21] For your scale, the practical challenges are: - **Tether weight**: The power cable itself adds mass that the kite/balloon must support - **FAA restrictions**: In Oviedo, you'd need to stay below 150ft AGL for untethered moored balloons (14 CFR 101), or get a waiver - **Wind loading**: Florida afternoon storms would require rapid retrieval - A **smaller-scale version** (a tethered helium balloon lifting a lightweight ~500W panel to 30–50ft) could clear nearby trees/shadows and gain meaningful irradiance improvement without regulatory headaches ## Other Tricks That Help - **Bifacial cells**: If you can source them, they collect reflected light from the ground underneath, adding 5–15% output — especially effective over light-colored surfaces like concrete[^1_3] - **Ground-level reflectors**: Cheap mylar or white tarps under/around the panel can concentrate extra light, acting as poor-man's concentrators - **ESP32-based MPPT charge controller**: Open-source designs exist that handle up to 1 kW with WiFi telemetry for monitoring — a perfect sub-project[^1_11] - **Panel-level optimizers**: Each sub-panel gets its own MPPT, preventing one weak section from dragging down the whole array[^1_22] - **Seasonal tilt adjustment**: Even without a full tracker, manually adjusting tilt angle monthly captures most of the fixed-tilt-to-single-axis gain ## Realistic Build Path For a satisfying, iterative hacking project: 1. **Start small**: Build a 200–300W test panel from a \$50 grab bag of broken cells using the jig method — prove your soldering process and measure actual output 2. **Add MPPT**: Flash an ESP32 MPPT charge controller, get telemetry working 3. **Scale up**: Build 4–6 more sub-panels, wire through a switching matrix you design 4. **Add tracking**: Single-axis first (one linear actuator + Arduino), then upgrade to dual-axis 5. **Go foldable**: Mount sub-panels on hinged frames that deploy from the car roof With B-grade mono cells, single-axis tracking, and your dynamic reconfiguration, you could realistically hit **10 kWh/day from a ~13 m² (~12ft square) array** for well under \$500–600 in materials — and have a deeply satisfying build along the way. <span style="display:none">[^1_23][^1_24][^1_25][^1_26][^1_27][^1_28][^1_29][^1_30][^1_31][^1_32][^1_33][^1_34][^1_35][^1_36][^1_37][^1_38][^1_39][^1_40][^1_41][^1_42][^1_43][^1_44][^1_45][^1_46][^1_47][^1_48][^1_49][^1_50][^1_51][^1_52][^1_53][^1_54][^1_55][^1_56][^1_57][^1_58][^1_59][^1_60]</span> <div align="center">⁂</div> [^1_1]: https://www.turbinegenerator.org/solar/florida/oviedo/ [^1_2]: https://www.youtube.com/watch?v=7VGYRjEt128 [^1_3]: https://diysolarforum.com/threads/used-panels-as-low-as-0-10-watt.78122/ [^1_4]: http://diyprojects.eu/tabbing-solar-cells-using-simple-jig/ [^1_5]: https://www.instructables.com/Make-a-high-powered-solar-panel-from-broken-solar-/ [^1_6]: https://www.siliconsolar.com/product/scrap-solar-cells-1-lb/ [^1_7]: https://www.youtube.com/watch?v=JJTpWPHAoUk [^1_8]: https://www.academia.edu/29805639/Optimization_of_photovoltaic_energy_production_through_an_efficient_switching_matrix [^1_9]: https://www.bohrium.com/paper-details/a-scalable-hierarchical-dynamic-pv-array-reconfiguration-under-partial-shading/947687135253626897-4370 [^1_10]: https://ece.northeastern.edu/groups/power/lehman/Publications/Pub2008/2008_M_Nguyen.pdf [^1_11]: https://www.instructables.com/DIY-1kW-MPPT-Solar-Charge-Controller/ [^1_12]: https://shieldenstrut.com/blogs/news/single-axis-vs-dual-axis-solar-trackers/ [^1_13]: https://www.instructables.com/DIY-Portable-Single-Axis-Solar-Tracker/ [^1_14]: https://www.youtube.com/watch?v=Okvyq91Q-0k [^1_15]: https://www.instructables.com/Simple-Dual-Axis-Solar-Tracker/ [^1_16]: https://www.youtube.com/watch?v=ZWBpYbpnXvM [^1_17]: https://prepperhideout.com/blogs/preparedness-information/powerfilm-foldable-solar-panels-best-portable-solar-panels-for-camping-amp-off-grid-living [^1_18]: https://www.powerfilmsolar.com/products/foldable-solar-panels [^1_19]: https://news.cnrs.fr/opinions/solar-energy-aims-for-the-sky-0 [^1_20]: https://www.ecoportal.net/en/say-goodbye-to-solar-panels-these/1925/ [^1_21]: https://web.wpi.edu/Images/CMS/UGP/High_Altitude_Energy.pdf [^1_22]: https://www.solarmanpv.com/mppt-power-optimizer-for-maximizing-solar-energy-output.html [^1_23]: https://solarbear.com/2024/09/19/how-many-solar-panels-does-it-take-to-charge-a-hybrid/ [^1_24]: https://greendiary.com/diy-way-making-broken-solar-panels-work/ [^1_25]: https://peb.steelprogroup.com/solar-structure/canopy/charge-ev-with-solar-panel/ [^1_26]: https://www.solarreviews.com/blog/how-much-solar-do-i-need-to-charge-my-electric-car [^1_27]: https://www.youtube.com/watch?v=wRIVNT3wqwM [^1_28]: https://www.instructables.com/DIY-Solar-Panel/ [^1_29]: https://www.solar.com/learn/how-many-solar-panels-does-it-take-to-fuel-an-electric-car/ [^1_30]: https://diysolarhomes.com/blog/diy-solar-panels/soldering-photovoltaic-pv-cells-together-tips/ [^1_31]: https://www.youtube.com/watch?v=wU5A6RspXpE [^1_32]: https://www.energysage.com/ev-charging/how-many-panels-do-you-need-for-your-ev/ [^1_33]: https://www.youtube.com/watch?v=Q8Mjy0T_8Vc [^1_34]: https://www.energydawnice.com/solar-panel-output-per-square-meter/ [^1_35]: https://www.linkedin.com/posts/geetesh-singh-509aa239_solarstring-mppt-solarinverter-activity-7348946339562430464-pGPU [^1_36]: https://www.ny-engineers.com/blog/understanding-solar-panel-efficiency-what-does-it-really-mean [^1_37]: https://solartechonline.com/blog/how-much-energy-does-solar-panel-produce/ [^1_38]: https://dc-opportunities.com/wp-content/uploads/2024/08/Design-of-a-Cell-String-Level-Maximum-Power.pdf [^1_39]: https://www.solarendowment.org/products/solar-panels-watts-per-square-meter/ [^1_40]: https://ywang393.expressions.syr.edu/wp-content/uploads/2016/07/Near-optimal-dynamic-module-reconfiguration-in-a-photovoltaic-system-to-combat-partial-shading-effects.pdf [^1_41]: https://www.cleanenergyreviews.info/blog/most-efficient-solar-panels [^1_42]: https://www.sciencedirect.com/science/article/abs/pii/S0142061520307171 [^1_43]: https://www.siliconsolar.com/product-category/solar-panels-cells/photovoltaic-solar-cells/broken-solar-cells/ [^1_44]: https://sunrise-sunset.org/us/oviedo-fl [^1_45]: https://www.youtube.com/watch?v=a-51KqjXZ6A [^1_46]: https://www.reddit.com/r/solar/comments/ik6paf/the_craigslist_steal_of_the_century_five_200_watt/ [^1_47]: https://nomadseason.com/climate/united-states/florida/oviedo.html [^1_48]: https://weatherspark.com/y/17723/Average-Weather-in-Oviedo-Florida-United-States-Year-Round [^1_49]: https://fortune.com/article/used-solar-panels-sold-on-facebook-and-ebay-have-cult-following/ [^1_50]: https://www.timeanddate.com/sun/@4167348 [^1_51]: https://meridional.eu/news/airborne-wind-energy-takes-flight-kites-as-the-next-frontier/ [^1_52]: https://newatlas.com/sitemap-201207.xml [^1_53]: https://pureportal.bcu.ac.uk/en/publications/matlab-simulink-analysis-of-switch-matrix-for-optimal-solar-pv-ar/ [^1_54]: https://www.facebook.com/groups/ecoflowclub/posts/2052953088530093/ [^1_55]: https://goalzero.com/collections/portable-solar-panels [^1_56]: https://goalzero.com/collections/foldable-solar-panels [^1_57]: https://www.reddit.com/r/solar/comments/ul8hw2/hi_im_relatively_new_here_just_wanted_to_know_how/ [^1_58]: https://www.solarreviews.com/blog/portable-solar-panels-are-they-worth-getting [^1_59]: https://ywang393.expressions.syr.edu/wp-content/uploads/2016/07/Fast-photovoltaic-array-reconfiguration-for-partial-solar-powered-vehicles.pdf [^1_60]: https://iallpowers.com/collections/foldable-solar-panel --- # how big would it have to be if i: - navigated altitude regulations and kept the angle on 2 axes successfully - reflected and focused extra sunlight onto the cells until i reached unreasonable reflector size or diminishing returns With altitude, dual-axis tracking, and heavy concentration, the panel area can shrink to just a few square feet — but only if you handle heat and optics carefully. ## Step 1: Upper Bound on Available Sunlight - Above the atmosphere, the **solar constant** is about **1361 W/m²**.[^2_1][^2_2] - At ground under AM1.5 conditions (clear sky, sun not too low), the standard irradiance used for panel ratings is **1000 W/m²**.[^2_3][^2_4] - So lifting a panel with a balloon/kite high enough to be above most clouds but still within the atmosphere doesn’t multiply energy by orders of magnitude; you’re still in the **~1000–1100 W/m²** ballpark at cell level, just with **more consistent full-sun time** and fewer losses from clouds/haze.[^2_5] Dual-axis tracking keeps you close to that peak for more of the day but doesn’t change the per‑m² limit; it just increases “effective sun hours.” ## Step 2: Concentrating Sunlight For flat solar cells, you can use **mirrors or lenses** to concentrate light: - Theoretical concentration ratios of **100–1000×** are used in concentrated PV (CPV) research, with **100×** being practical with parabolic troughs/dishes.[^2_6] - Experimental systems have hit **~1000–1300 suns** concentration with Fresnel/lens + reflective films, but that’s lab-level optical alignment and cooling.[^2_7] - Under concentration, CPV cells can reach **39–47% efficiency** with multi-junction devices, versus 20–23% for regular silicon.[^2_8][^2_9] For *DIY with silicon cells*: - Silicon cells start overheating and losing efficiency when concentration goes much above **5–10 suns** unless you add serious heat sinking and maybe liquid cooling. - Beyond ~10–20×, your thermal management becomes a primary design problem: you’re dumping tens of kilowatts of heat into a tiny cell area. So a **reasonable DIY concentration target** is on the order of **5–10×** with good passive cooling; higher is not impossible but gets progressively more unreasonable in complexity. ## Step 3: Recompute Area with Concentration Let’s assume: - Dual-axis tracking: effective irradiance near **1000 W/m²** most of the day.[^2_4] - Modern good cells: **21% efficiency** (mono PERC) is commercial reality.[^2_10] - 10 kWh/day target. - You get **7 peak-equivalent sun hours/day** with good tracking and high, clear positioning. - You use optics to achieve **C× concentration**, so the effective irradiance on the cell is $C \times 1000$ W/m² (up to thermal limits). Energy per square meter per day: $$ E = 1000 \times C \times 0.21 \times 7 \text{ Wh/m²} = 1470C \text{ Wh/m²} $$ So the required cell area $A$ for 10 kWh is: $$ A = \frac{10{,}000}{1470C} \text{ m²} $$ Plugging in: - **No concentration (C = 1)**: $A \approx 6.8 \text{ m²}$ → ~73 ft² → about 8.5 ft × 8.5 ft (this matches the ~8.4 m² estimate for high-eff cells with dual-axis tracking from before). - **C = 5 (5× concentration)**: $A \approx 1.36 \text{ m²}$ → ~14.6 ft² → about 4 ft × 4 ft. - **C = 10 (10× concentration)**: $A \approx 0.68 \text{ m²}$ → ~7.3 ft² → about 2.7 ft × 2.7 ft. So, in the “reasonably insane” regime (dual-axis, well‑cooled silicon, 5–10× concentration), you can shrink the **actual cell area** to somewhere between a **4×4 ft tile** and a **3×3 ft tile** for 10 kWh/day. The **reflector/optics area**, though, must still gather the total sunlight: - At **5×**, you need ~5× the cell area in mirrors/reflectors. For a 4×4 ft cell tile (~16 ft²), that’s ~80 ft² of reflectors (~9×9 ft footprint). - At **10×**, a 3×3 ft cell (~9 ft²) wants ~90 ft² of collection area (~9.5×9.5 ft). You gain in **cell cost and cell area**, but you still end up managing roughly the same *total* optical footprint as a non-concentrated 10 kWh/day array — just re-imagined as a small, intensely illuminated receiver plus a larger field of reflectors. ## Step 4: Where Do Diminishing Returns Kick In? A few constraints start biting as you crank concentration: - **Thermal limit of silicon**: Efficiency drops by roughly 0.3–0.5% absolute per °C above 25°C. High concentration without aggressive cooling can push cell temperature well beyond 80–100°C, negating electrical gains and risking damage. - **Optical accuracy**: To hit 50–100× concentration, your reflectors or lenses must track the sun with high precision (fractions of a degree), and surfaces must be clean and low-scatter.[^2_6][^2_7] - **Mechanical complexity**: The receiver must stay at the focal point; misalignment wastes the advantage quickly. - **Atmospheric scattering \& clouds**: Even aloft, you’re still under AM1.x solar spectrum; concentration doesn’t increase the *total* photons available, just packs them into smaller area. Practically, for your “fun but not totally masochistic” project: - **5× is quite reasonable** with simple mirrors and big, forgiving optics. - **10×** is doable with good heat sinks and thicker aluminum backing. - Beyond that, you’re pushing into real CPV engineering territory. ## Synthesis: Your “Extreme But Buildable” Design If you: - Use **dual-axis tracking** to keep a small receiver normal to the sun all day. - Lift the receiver and maybe some reflectors high enough to be above local clutter/clouds where legal. - Use **5–10× mirrors or lens-based concentration** with aggressive passive cooling. Then: - **Cell area**: Somewhere in the **0.7–1.5 m² range** (7–16 ft²), roughly a **3×3 to 4×4 ft panel**. - **Total optical footprint (cell + reflectors)**: Still roughly **8–10 ft square** to collect enough sunlight for 10 kWh/day. - You’ve traded a big, flat array for a compact, high‑intensity receiver + a “light bucket” made of reflectors. So the array **doesn’t have to be anywhere near car-sized** in terms of *cell* area. In the concentrated, dual-axis, quasi-ideal regime you’re describing, your **active silicon surface could be roughly a small tabletop**, with the rest of the size expressed as “cheap mirrors and geometry” rather than expensive cells. <span style="display:none">[^2_11][^2_12][^2_13][^2_14][^2_15]</span> <div align="center">⁂</div> [^2_1]: https://www.sciencedirect.com/topics/physics-and-astronomy/solar-constant [^2_2]: https://en.wikipedia.org/wiki/Solar_constant [^2_3]: https://enlitechnology.com/blog/measuring-atmospheric-mass-am0-am1-5-and-am1-5g-attenuation-of-sunlight-through-the-atmosphere/ [^2_4]: https://www.pveducation.org/pvcdrom/properties-of-sunlight/air-mass [^2_5]: https://www.jinyi-solar.com/Solar_Basics/solar-radiation.html [^2_6]: https://www.nature.com/articles/s41377-021-00465-1 [^2_7]: https://www.sciencedirect.com/science/article/abs/pii/S0038092X2400121X [^2_8]: https://en.wikipedia.org/wiki/Solar-cell_efficiency [^2_9]: https://www.sciencedirect.com/science/article/pii/S2590123025005031 [^2_10]: https://undecided.tech/exploring-solar-panel-efficiency-breakthroughs-in-2020/ [^2_11]: https://www.facebook.com/groups/420911468613467/posts/1955186605185938/ [^2_12]: https://earth.gsfc.nasa.gov/climate/projects/solar-irradiance/science [^2_13]: https://www.cliffsnotes.com/tutors-problems/Earth-Science/49158347-The-solar-constant-is-approximately-1361Wm-2-and-based-on-the/ [^2_14]: https://andymaypetrophysicist.com/2018/09/19/how-constant-is-the-solar-constant/ [^2_15]: https://pmc.ncbi.nlm.nih.gov/articles/PMC12259506/ --- # can you figure out the gains vs DIY-with-palsy challenge to figure out the _easiest_ way to get 10kWh in a _week_ on a shoestring budget doing everything by hand with cheap-as-dirt parts? The easiest way to get 10 kWh in a week, by hand, on a shoestring, is to forget fancy concentration/altitude and just scavenge a few hundred watts of used panels or broken cells, mounted fixed, and let Florida’s sun do the work. ## Target: 10 kWh per Week in Oviedo Oviedo gets about **5 peak sun hours/day** with fixed-tilt panels.[^3_1] 10 kWh/week is about **1.43 kWh/day**. Required panel power: $$ \text{Power} = \frac{1.43 \text{ kWh/day}}{5 \text{ h/day}} \approx 0.29 \text{ kW} = 290 \text{ W} $$ So if you can get **~300 W of real output**, fixed, you’re done. With DIY inefficiencies / shading / suboptimal angle, being conservative and aiming for **400–500 W nameplate** is very comfortable. ## Option 1: Scavenged Used Panels (Easiest by far) Used panels from solar farms and upgrades are routinely available for **\$0.06–0.15/W** if you’re willing to pick them up locally. Santan Solar and similar outfits have used 250 W panels at **~\$0.06/W** in bulk, and local upgrades/freebies are common.[^3_2][^3_3] For your target: - 2 × 250 W used panels = 500 W nameplate - At 60–15 cents/W, that’s **\$30–\$75 total** for panels[^3_3][^3_2] - No cell soldering, just: - Bolt them to a scrap-wood or Unistrut frame at ~latitude tilt - Run MC4/screw terminals into a cheap MPPT charge controller **Work level**: - Minimal hand dexterity: a few bolt holes, crimping, and screw terminals. - No fiddly soldering of shards. - Low risk of “I spent 12 hours and broke half my cells.” This is overwhelmingly the **easiest 10 kWh/week** path. ## Option 2: Scrap/Broken Cells, Built by Hand Scrap cell bags: about **100–120 W of cells per lb** for ~\$20, i.e. **~\$0.15/W**. A “palsy-friendly” build can be made with big jigs and slow, forgiving assembly:[^3_4][^3_5] ### How much scrap? Aim for ~400–500 W nameplate: - At ~100 W/lb, you need **4–5 lb of scrap cells** - At ~\$20/lb → **\$80–\$100 in cells**[^3_4] ### Dexterity-friendly build tricks - **Big cell mosaics** in plywood “egg crate”: - Cut shallow pockets or glue on tile spacers in a grid so shards self-align.[^3_6] - This compensates for shaky hands: you drop shards into compartments instead of placing them precisely. - Use **wide, pre-tinned bus bars and tabbing wire** so aiming isn’t microscopic.[^3_7][^3_8] - Lower-temperature, chisel-tip iron; clamp the work; let both hands rest on guides. - Overbuild series/parallel so a few bad joints or cracked shards don’t kill a string. Even so, panel-building from shards is many hours of repetitive fine work. It’s doable and fun as a craft, but objectively **higher “palsy challenge”** than just bolting down used panels. ## Power Math for the Scrap Approach Take **400 W of roughly 15–18% efficient cells**, fixed at 5 h/day: - Ideal daily: 400 W × 5 h = 2 kWh/day[^3_1] - After wiring/angle/heat losses, call it 60–70%: **1.2–1.4 kWh/day** - That’s **8–10 kWh/week**, right on target. So: - **Cell area**: 400 W of typical silicon is ~2–2.5 m² (20–27 ft²). - **Materials**: - Scrap cells: ~\$80–100[^3_4] - Glass/plexi + silicone/epoxy: ~\$50–100 - Tabbing wire / bus bar / solder: ~\$30–40[^3_8] - Wood/backing + screws: ~\$20–30 - Total: roughly **\$180–270**, heavy on hand labor. ## Gains vs DIY Difficulty Framing it as “gain per cognitive/motor pain”: - **Used full panels** - Gain: 10 kWh/week easily with 500 W, fixed tilt, in Oviedo.[^3_1] - Cost: \$30–75 for panels if you hunt deals.[^3_2][^3_3] - Challenge: very low; basic hand tools, no fine soldering. - This is the **sweet spot for “easiest”**. - **Scrap/broken cells** - Gain: still 10 kWh/week, but more satisfying hacker points. - Cost: ~\$200 total for equivalent capacity.[^3_4] - Challenge: high; hundreds of solder joints, fragile parts, jig building. - Best if you want the project more than the energy. - **Dynamic reconfiguration / trackers / concentration** - Gains: more kWh per watt, or fewer panels. - Cost \& challenge: skyrocket; precision mechanics, control firmware, optics, heat management. - Overkill for **10 kWh/week**; the easy win is just **more cheap panel area**. ## Recommendation for “Easiest 10 kWh/Week” Given your constraints: 1. **Scrounge 400–500 W of used panels locally** at ~\$0.06–0.15/W (Facebook, OfferUp, installers, Santan, etc.).[^3_3][^3_2] 2. Build a **simple fixed frame** at ~lat tilt, oriented south. 3. If you want “tinker bonus”: - Add a **very crude single-axis tracker** later (hinge + hand-adjust or a single actuator). - Or add a microcontroller logger/MPPT, which uses brainpower instead of fine motor control. That gets you your 10 kWh/week in Florida with **the least fiddly handwork**, using **cheap-as-dirt parts**, and leaves the more intricate shard/jig/CPV craziness for when you want the challenge, not when you just want free-ish car juice. <span style="display:none">[^3_10][^3_11][^3_12][^3_13][^3_14][^3_15][^3_16][^3_17][^3_18][^3_9]</span> <div align="center">⁂</div> [^3_1]: https://www.turbinegenerator.org/solar/florida/oviedo/ [^3_2]: https://diysolarforum.com/threads/used-panels-as-low-as-0-10-watt.78122/page-2 [^3_3]: https://www.reddit.com/r/SolarDIY/comments/14anjvt/used_pv_at_010_per_watt_need_large_super_low_cost/ [^3_4]: https://www.siliconsolar.com/product/scrap-solar-cells-1-lb/ [^3_5]: https://www.youtube.com/watch?v=KWrHt06qhCQ [^3_6]: http://diyprojects.eu/tabbing-solar-cells-using-simple-jig/ [^3_7]: https://www.instructables.com/Make-a-high-powered-solar-panel-from-broken-solar-/ [^3_8]: https://diysolarhomes.com/blog/diy-solar-panels/soldering-photovoltaic-pv-cells-together-tips/ [^3_9]: https://www.facebook.com/groups/365290727876426/posts/1090896818649143/ [^3_10]: https://www.reddit.com/r/solar/comments/182jesa/solar_module_prices_may_reach_010w_by_end_2024/ [^3_11]: https://www.facebook.com/groups/365290727876426/posts/1151321362606688/ [^3_12]: https://www.youtube.com/watch?v=Nk5lJqAOuEY [^3_13]: https://palmetto.com/local/peak-sun-hours/ [^3_14]: https://www.youtube.com/watch?v=nN48JCtndSc [^3_15]: https://www.youtube.com/watch?v=NTX_tK_eYbE [^3_16]: https://urbansolar.com/understanding-floridas-sun-hours-how-much-power-can-your-home-actually-produce/ [^3_17]: https://www.reddit.com/r/SolarDIY/comments/1adln5x/solar_panel_cost_too_good_to_be_true/ [^3_18]: https://www.siliconsolar.com/product-category/solar-panels-cells/photovoltaic-solar-cells/broken-solar-cells/ --- # can you search around and find the cheapest quick reliable source for some solar cells or panels in a nearby county or online? Here are the cheapest, most practical options I found, ranked by "least hassle for someone near Oviedo": ## Best Local Options (No Shipping Cost) ### Facebook Marketplace Orlando This is your absolute cheapest bet right now. Active listings include **245W used panels at \$30** and **new 260W panels at \$57** in the Orlando area. People regularly post decommissioned commercial panels at **\$0.10–0.17/W** — you just need to check frequently and be ready to drive. Search "solar panels" on Facebook Marketplace filtered to Orlando; deals move fast.[^4_1][^4_2] ### Craigslist Orlando Currently listed: **"Miscellaneous Solar Panels" in Edgewood for \$100** (that's right next door to you), and a **60W panel in Winter Park for \$30**. There's also a **solar panel removal job in Central FL for \$150** — sometimes these listings mean "come help remove them and take some home". Worth messaging.[^4_3][^4_4] ### A1 SolarStore — Orlando Pickup (32809) They have a fulfillment center in Orlando with clearance panels available for **local pickup as soon as March 23**. Their clearance mono panels run **\$0.26–0.49/W** new — so a 395W Canadian Solar panel might be around \$103, or a 410W Mission Solar around \$107. These are *new* panels with warranty, just clearance stock. Not the absolute cheapest, but zero guesswork on condition.[^4_5][^4_6][^4_7] ## Best Online Options ### SanTan Solar (Gilbert, AZ — ships to FL) The current rock-bottom prices with their **BOGO free deal on used panels** (code: `lovebogo`):[^4_8][^4_9] | Panel | List Price | BOGO Price Each | \$/Watt | | :-- | :-- | :-- | :-- | | Used SSG 250W (cracked vinyl) | \$35 | **\$17.50** | **\$0.07/W** | | Used SSG 250W (green busbars) | \$30 | **\$15** | **\$0.06/W** | | Used Trina 245W (snail trail) | \$39 | **\$19.50** | **\$0.08/W** | | Used SST 250W (snail trails) | \$40 | **\$20** | **\$0.08/W** | The catch: **shipping to Florida is expensive** — roughly \$125–350+ depending on quantity. For just 2 panels, shipping might cost more than the panels. It makes sense if you buy 10+ to amortize shipping. A pallet of 24 blemished 250W panels is \$480 (\$20/panel, \$0.08/W) before shipping.[^4_10][^4_11][^4_8] ### Signature Solar (Texas) New REC 350W panels have been spotted at **\$0.14–0.17/W** in pallet quantities. But shipping to Florida runs \$650+ for a pallet, which kills the deal unless you're buying a huge amount.[^4_12] ## The "Easiest 500W for Under \$100" Play For your 10 kWh/week target (needing ~400–500W): 1. **Check Facebook Marketplace Orlando daily** for ~2 weeks. You'll almost certainly find 2× 250W+ panels for \$50–80 total within driving distance.[^4_2][^4_1] 2. **Failing that**, grab that Edgewood Craigslist listing (\$100 for miscellaneous panels — Edgewood is basically next to Oviedo).[^4_3] 3. **If you want guaranteed supply today**, order 2 panels from SanTan Solar with BOGO — 4× 250W = 1 kW for ~\$60–70 in panels + ~\$125 flat-rate shipping = **~\$190 delivered for a full kilowatt**. That's double what you need and leaves room for mismatch losses.[^4_11][^4_8] The Facebook/Craigslist route is the true shoestring path — people upgrading their systems just want these panels *gone*, and you're a short drive from the densest solar market in Central Florida. <span style="display:none">[^4_13][^4_14][^4_15][^4_16][^4_17][^4_18][^4_19][^4_20][^4_21][^4_22][^4_23][^4_24][^4_25][^4_26][^4_27][^4_28][^4_29][^4_30][^4_31][^4_32][^4_33][^4_34][^4_35][^4_36][^4_37][^4_38]</span> <div align="center">⁂</div> [^4_1]: https://www.reddit.com/r/SolarDIY/comments/1n0wc1c/cheap_used_pv_panels_on_facebook_marketplace_id/ [^4_2]: https://www.facebook.com/marketplace/orlando/solar-panels/ [^4_3]: https://orlando.craigslist.org/search/sss?query=solar+panels [^4_4]: https://orlando.craigslist.org/search/ela?purveyor=owner\&query=solar+panels [^4_5]: https://a1solarstore.com/solar-panels/florida/orlando.html [^4_6]: https://a1solarstore.com/clearance-solar-panels.html [^4_7]: https://a1solarstore.com/fulfillment-center-fl-orlando-2.html [^4_8]: https://www.santansolar.com/condition/used/ [^4_9]: https://www.santansolar.com [^4_10]: https://www.youtube.com/watch?v=ftvKkMcibdw [^4_11]: https://diysolarforum.com/threads/santan-solar-deal.73373/ [^4_12]: https://diysolarforum.com/threads/0-17-cents-a-watt-panels-signature-solar.102788/ [^4_13]: https://news.yahoo.com/bright-idea-orange-county-offers-120000578.html [^4_14]: https://www.reddit.com/r/SolarDIY/comments/1l7ci7w/fair_price_for_used_panels/ [^4_15]: https://www.clickorlando.com/news/local/2024/02/26/more-than-5k-used-solar-panels-to-be-given-away-in-orange-county-heres-how-to-sign-up/ [^4_16]: https://www.youtube.com/watch?v=e54ltxdTUYs [^4_17]: https://solarrecycling.com/sell-solar-panels/ [^4_18]: https://diysolarforum.com/threads/wanted-a-few-panels-east-coast-central-florida-area.92777/ [^4_19]: https://www.reddit.com/r/SolarDIY/comments/1iatumx/santan_solar_is_offering_10_280w_poly_panels_for/ [^4_20]: https://orangecounty.craigslist.org/search/sss?query=solar+panels [^4_21]: https://www.santansolar.com/product-category/solar-panels/condition/used-solar-panels/ [^4_22]: https://webuysolar.net [^4_23]: https://www.santansolar.com/contact-us/ [^4_24]: https://www.reddit.com/r/SolarDIY/comments/1ma2bxi/signature_solar_quote_102w/ [^4_25]: https://diysolarforum.com/threads/a1-solarstore-18-large-panels.101880/ [^4_26]: https://www.cnet.com/home/solar/solar-panel-cost/ [^4_27]: https://www.santansolar.com/about-us/frequently-asked-questions/ [^4_28]: https://a1solarstore.com/blog/solar-panel-costs-prices-and-savings.html [^4_29]: https://www.youtube.com/watch?v=By6q_USt888 [^4_30]: https://recsolarpanels.com/solar-panels-florida/ [^4_31]: https://www.santansolar.com/product-category/solar-panels/mfg/santan-solar/ [^4_32]: https://offerup.com/item/detail/050db284-c136-31ce-95ae-c34eb65dc144 [^4_33]: https://aarauctions.com/servlet/Search.do?auctionId=3885 [^4_34]: https://www.facebook.com/marketplace/category/solar-panels/ [^4_35]: https://www.reddit.com/r/diySolar/comments/1mjk4t6/san_tan_solar_coupon_codes_15_and_20_on_pallet_of/ [^4_36]: https://www.facebook.com/marketplace/category/search/?query=solares-en-venta-baratos-en-orlando [^4_37]: https://www.santansolar.com/product-category/solar-panels/price-range/0-49/ [^4_38]: https://www.facebook.com/marketplace/category/search/?query=cheap-like-new-solar-panels --- # well i'm not set up with facebook and have trouble remembering and doing things in an ongoing manner and shouldn't spend more than like \$50 at the very most ... what makes sense to consider a prototype? Given your constraints — under \$50, no Facebook, no ongoing monitoring, just a one-shot purchase — here's what actually makes sense: ## Best Bet: IDEAS For Us Solar Giveaway (FREE Panels) This is almost too good. **IDEAS For Us** ran the "Great Solar Giveaway" in 2024 giving away **5,800+ free 175W panels** from the Orange County Convention Center, and their website shows a **2025 edition** too. These are 19-year-old SolarWorld 175W mono panels, 5.2 ft × 2.6 ft, 33 lbs each — still functional, just old. The pickup location was **right in Orange County**, essentially your backyard. You fill out a form, they confirm, you go grab panels. No ongoing checking needed — just one signup.[^5_1][^5_2][^5_3] **Check if they still have stock**: [ ideasforus.org/solargiveaway](https://ideasforus.org/solargiveaway/). Even one panel (175W) gets you ~6 kWh/week in Oviedo for the cost of gas to drive there. Two panels = your 10 kWh/week target, free.[^5_3] ## If the Giveaway Is Gone: eBay, Free Shipping A brand called **Rvpozwer** on eBay was selling **100W panels for \$35 with free shipping** from a US warehouse. That's within budget and zero hassle — order once, it shows up at your door. A single 100W panel gets you ~3.5 kWh/week, so you'd want two (\$70, slightly over budget) or one as a prototype to prove the concept first.[^5_4] For a strict **under-\$50 prototype**, a single 100W panel at \$35 shipped is your easiest bet. It produces ~0.5 kWh/day or ~3.5 kWh/week — not your full 10 kWh target, but enough to prove the pipeline works and start trickling charge into the car.[^5_4] ## Craigslist Orlando (One-Shot Check, Right Now) You don't need to monitor it ongoing — just check it once, today. There was a **"Miscellaneous Solar Panels" listing in Edgewood for \$100**. That's over budget, but people selling "miscellaneous" panels on Craigslist often take offers. Sending a "\$40 cash, I'll come today" message isn't unreasonable. Edgewood is ~10 minutes from Oviedo.[^5_5] ## Prototype Sizing For a proof-of-concept under \$50, you're realistically looking at **100–175W**, which gives you: | Source | Watts | Cost | Weekly kWh (Oviedo) | Effort | | :-- | :-- | :-- | :-- | :-- | | IDEAS giveaway (if available) | 175–350W (1–2 panels) | **Free** | 6–12 kWh | Drive to Orange County, fill form | | eBay 100W panel (Rvpozwer etc.) | 100W | **~\$35 shipped** | ~3.5 kWh | Order online, wait for delivery | | Craigslist Edgewood (lowball offer) | Unknown | **~\$40?** | Depends | One message + one drive | ## What You'd Still Need To actually charge the hybrid from any of these, you need a charge controller. A cheap **PWM controller is ~\$10–15** on Amazon or eBay, which stays within your \$50 budget if you grab a free panel. For the hybrid specifically, you'd charge a 12V battery as an intermediary, or use the panel to offset house grid draw while the car charges from the wall — either way the electrons end up in the same place.[^5_6] **My honest recommendation**: Hit the IDEAS For Us giveaway page right now. If they still have panels, you walk away with 175–350W for free and spend \$10–15 on a charge controller. That's your entire 10 kWh/week prototype for under \$20.[^5_3] <span style="display:none">[^5_10][^5_11][^5_12][^5_13][^5_14][^5_15][^5_16][^5_17][^5_18][^5_19][^5_20][^5_21][^5_22][^5_23][^5_24][^5_25][^5_26][^5_27][^5_28][^5_29][^5_30][^5_7][^5_8][^5_9]</span> <div align="center">⁂</div> [^5_1]: https://cleantechnica.com/2024/02/24/the-great-solar-giveaway-is-offering-thousands-of-free-175w-solar-panels-in-orlando-fl/ [^5_2]: https://news.yahoo.com/bright-idea-orange-county-offers-120000578.html [^5_3]: https://ideasforus.org/solargiveaway/ [^5_4]: https://diysolarforum.com/threads/rvpozwer-panels-on-ebay-100w-for-35-others-similarly-discounted-free-shipping.114372/ [^5_5]: https://orlando.craigslist.org/search/sss?query=solar+panels [^5_6]: https://footprinthero.com/diy-solar-car-battery-charger [^5_7]: https://www.youtube.com/watch?v=ftvKkMcibdw [^5_8]: https://www.reddit.com/r/SolarDIY/comments/1lhbixh/are_the_100_200w_solar_panels_on_ebay_trustworthy/ [^5_9]: https://www.reddit.com/r/harborfreight/comments/l0xw4q/why_are_hf_solar_panels_so_expensive_2watt_for/ [^5_10]: https://www.reddit.com/r/SolarDIY/comments/1bc60ob/sick_of_scams_looking_for_trustable_east_coast/ [^5_11]: https://www.harborfreight.com/100-watt-super-lightweight-foldable-solar-panel-70474.html [^5_12]: https://www.reddit.com/r/SolarDIY/comments/1iatumx/santan_solar_is_offering_10_280w_poly_panels_for/ [^5_13]: https://www.harborfreight.com/100-watt-amorphous-solar-panel-kit-63585.html [^5_14]: https://diysolarforum.com/threads/san-tan-solar-shipping-cost.106017/ [^5_15]: https://www.harborfreight.com/lawn-garden/outdoor-living/solar/panel-kits.html [^5_16]: https://www.santansolar.com [^5_17]: https://www.harborfreight.com/home/electrical/solar.html [^5_18]: https://www.santansolar.com/product-category/solar-panels/price-range/0-49/ [^5_19]: https://www.harborfreight.com/100-watt-monocrystalline-solar-panel-kit-70735.html [^5_20]: https://www.santansolar.com/product-category/solar-panels/ [^5_21]: https://www.harborfreight.com/100-watt-monocrystalline-solar-panel-71049.html [^5_22]: https://www.reddit.com/r/solar/comments/178s9zf/diy_1200w_solar_car_charger/ [^5_23]: https://www.renogy.com/blogs/buyers-guide/what-size-solar-panel-do-i-need-to-charge-a-12v-battery [^5_24]: https://www.ecoflow.com/us/blog/how-to-charge-12v-battery-with-solar-panels [^5_25]: https://www.reddit.com/r/solar/comments/dkcc0q/free_solar_panels_from_craigslist_safe_to_get/ [^5_26]: https://www.youtube.com/watch?v=pYSUl9qfkgw [^5_27]: https://www.spectrumsolarpower.com [^5_28]: https://www.youtube.com/watch?v=ZWY_5zXU9Fs [^5_29]: https://www.reddit.com/r/orlando/comments/hxclrz/free_roof_solar_companies_is_this_a_scam/ [^5_30]: https://www.instructables.com/Lightweight-Solar-Panel-12V-Battery-Charger/
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