We just ran the ENTIRE design process. Twice. Same house. Same goals. Two COMPLETELY different results. The numbers are going to surprise you — and the monopoly hopes you NEVER see this page!
THE STARTING POINT
Same property. Same power needs. Same solar resource. ONE decision changes everything — the equipment path you choose.
- Location: Memphis, Tennessee (4.5 peak sun hours/day — national average)
- Goal: Power YOUR essentials — fridge, freezer, furnace fan, lights, internet, outlets
- Daily energy use: ~8 kWh
- Peak simultaneous load: ~2,000W
- Available space: South-facing garage roof, room for 6-8 panels
Two paths. Two price tags. VERY different results. Let’s show you EXACTLY what each one delivers!
PATH A: CONSUMER EQUIPMENT
The simple route. Grab a consumer all-in-one, plug in some panels, stack brand-matched batteries. Quick and easy. But the MPPT constraints are going to hit you — and NOBODY tells you this upfront!
Inverter: Consumer all-in-one, 3,000W continuous / 6,000W surge. MPPT specs: 2,400W max PV input, VOC 12-150VDC, 12A max input current. 120V output. Built-in transfer switch.
Panels: You WANT 6 x 400W = 2,400W nameplate, matching the MPPT max. Sounds GREAT on paper.
THE STRING MATH — WHERE THE TRUTH COMES OUT
Each panel: Voc 37.5V, Imp 12.8A.
- Three panels in series = 112.5V Voc. Under the 150V limit — good so far
- But one string of 3 panels draws 12.8A. That’s OVER the 12A max!
- Two parallel strings of 3 = 25.6A. WAY over!
WHAT YOU ACTUALLY BUILD
- Panels: 3-4 panels, ~1,200-1,600W of REAL solar input
- Battery: Two 2 kWh brand packs = 4 kWh total
- What it delivers: Handles summer overnight essentials. Falls SHORT in winter. Limited daily offset. But it’s simple and you can be up in a WEEKEND.
COST
| Item | Cost |
|---|---|
| Inverter + 2 battery packs | $2,500-$3,500 |
| 4 panels | $400-$600 |
| Mounting, wire, BOS | $500-$800 |
| TOTAL | $3,500-$5,000 |
PATH B: PROSUMER EQUIPMENT — THE PATRIOT’S CHOICE
MORE capability. MORE expandability. The MPPT window WORKS with you instead of against you. Takes more planning — but the numbers tell the REAL story!
Inverter: SRNE-based all-in-one, 5,000W continuous / 10,000W surge. MPPT specs: 5,500W max PV input, 120-500VDC range, 100A max input current. 120/240V split-phase. CAN bus battery communication. Generator input.
Panels: 8 x 400W = 3,200W nameplate. WELL within the 5,500W MPPT max — room to GROW!
STRING MATH — CLEAN AND SIMPLE
Each panel: Voc 37.5V, Vmp 31.2V, Isc 13.9A. MPPT window: 120-500V.
Single string of 8 panels:
- Voc = 8 x 37.5V = 300V (STC). Cold-adjusted: ~326V. Under 500V max. ✓
- Vmp at hottest = 8 x 31.2V = 249.6V (STC). Heat-adjusted: ~236V. Above 120V min. ✓
- Current: 13.9A Isc. Under 100A max. ✓
ONE string. ONE wire run. NO parallel headaches. The wider MPPT window handles temperature swings like a CHAMPION!
BATTERY
Two 5 kWh server rack batteries in parallel = 10 kWh total. At 85% usable depth of discharge — 8.5 kWh of REAL, usable energy. Enough for overnight essentials with ROOM TO SPARE. The rack holds two more units when YOU decide to expand!
WIRING AND BOS
PV wire from roof to inverter (~15 feet — voltage drop is negligible at 300V). DC combiner with fuses. DC disconnect. 10-circuit manual transfer switch. AC disconnect. Grounding to rod. Everything LABELED.
COST
| Item | Cost |
|---|---|
| Inverter | $800-$1,200 |
| 8 panels | $600-$1,000 |
| 2 x 5 kWh batteries | $1,500-$2,000 |
| Transfer switch | $300-$400 |
| Wire, conduit, fuses, disconnects, mounting | $800-$1,200 |
| TOTAL | $4,000-$6,000 |
THE NUMBERS DON’T LIE
| What You Get | Consumer Path | Prosumer Path |
|---|---|---|
| Solar input | 1,200-1,600W | 3,200W |
| Battery storage | 4 kWh | 10 kWh (8.5 usable) |
| Expansion room | Very limited | SIGNIFICANT |
| MPPT headroom | Constrained | WIDE OPEN |
| Setup complexity | Easy | Moderate |
| Total cost | $3,500-$5,000 | $4,000-$6,000 |
The consumer path gets you generating power FAST. The prosumer path takes more work upfront but delivers MASSIVELY more capability for barely more money!
Neither is wrong — but the math is CLEAR. For a small premium, the prosumer path delivers REAL energy independence. And that’s what we’re here for!
YOUR OUTPUT STATEMENT
When your design is done, you write THIS:
THAT is your system. THAT is your shopping list. THAT is the document that turns research into ACTION!
WHAT’S NEXT — TIME TO BUILD!
- Sourcing Equipment — Where to buy, what to AVOID, and how to get the BEST deal
- 200W Starter System — The simplest build to get STARTED
- 3.2kW Permitted System — The full prosumer build, step by step
- Back to Learn — Complete topic index
DATA SOURCED FROM: Component specifications from manufacturer datasheets (Voc, Vmp, Isc ratings). Cost estimates based on 2025-2026 retail pricing for consumer and prosumer standalone solar equipment. String calculations follow NEC temperature correction methodology. We show our math. THEY don’t.