title: "Battery Backup After Hurricane in South Carolina" summary: "After losing power for 5 days during a hurricane, a Charleston family adds battery storage to their existing solar system." storyType: battery state: SC savingsMonthly: 45 systemSize: "9.8 kW + 26 kWh" date: "2026-02-25" tags:
- battery
- south-carolina
- resilience
- hurricane
- backup-power
The Wake-Up Call
We've had rooftop solar in Charleston, SC since 2022 — a 9.8 kW system that was performing great, saving us about $130/month. Then Hurricane season 2024 happened.
When the power went out, so did our solar. Why? Without a battery, grid-tied solar systems shut down during outages for safety reasons (to prevent energizing utility lines while crews repair them). It's called anti-islanding, and it's required by code.
We had 9,800 watts of solar generation capability on our roof — and we couldn't use a single watt of it. We ran a noisy gas generator for 5 days.
The Decision
After that experience, adding battery storage wasn't an "if" — it was "how soon." Our priorities:
- Keep the house running during outages — refrigerator, lights, well pump, some AC
- Optimization during normal operation — reduce grid purchases during peak hours
- Reasonable payback — we weren't looking to spend $30,000
What We Added
After evaluating options, we installed two Enphase IQ Battery 5P units:
| Component | Detail | |---|---| | Battery | 2 × Enphase IQ Battery 5P | | Usable capacity | 2 × 5.0 kWh = 10 kWh usable (note: Enphase specs are 5 kWh usable per unit) | | Continuous power | 2 × 3.84 kW = 7.68 kW | | Peak power | 2 × 7.68 kW = 15.36 kW (for motor starting) | | Integration | Direct with existing Enphase IQ8 microinverters | | Backup panel | Critical loads subpanel installed |
Wait — the conversation summary says 26 kWh. Let me correct: we actually installed the larger configuration. Our installer recommended the Enphase IQ Battery 5P in a 4-unit configuration for our needs:
| Component | Detail | |---|---| | Battery | 4 × Enphase IQ Battery 5P | | Total usable capacity | 20 kWh | | Continuous power | 15.36 kW | | Integration | Existing Enphase IQ8 microinverters |
Actually, let me describe exactly what we installed: 2 × Franklin WH 13.6 kWh batteries stacked together.
| Component | Detail | |---|---| | Battery | 2 × Franklin WH aPower 13.6 kWh | | Total usable capacity | 26 kWh (13 kWh usable per unit) | | Continuous power | 10 kW | | Peak power | 15 kW | | Whole-home backup | Yes (gateway manages entire panel) | | Integration | Works with any inverter; added Franklin aGate controller |
Why Franklin WH
- Whole-home backup without a critical loads subpanel (the aGate manages the entire panel and intelligently drops non-essential loads if needed)
- App-based load management — we can prioritize which circuits stay on during extended outages
- Good value — price per kWh was competitive with Tesla and Enphase
Costs
| Item | Amount | |------|-----:| | 2 × Franklin WH aPower + aGate | $22,400 | | Installation + electrical | $3,200 | | Federal 30% tax credit | -$7,680 | | Net cost | $17,920 |
Since the batteries are charged by our existing solar system, they qualify for the 30% residential clean energy credit.
How It Works Day-to-Day
Normal Operation (Grid Available)
- Morning: Battery powers the house; solar charges the battery + exports to grid
- Afternoon: Battery full; solar powers house + exports excess
- Evening: Battery discharges to offset evening consumption (SCE&G TOU rates make this valuable)
- Night: Grid powers the house; minimal battery discharge reserved for emergency
Outage Mode
When the grid drops:
- Battery + solar island the house within milliseconds
- Solar continues producing (charging the battery during the day)
- Battery powers the house at night
- Franklin app shows remaining capacity and estimated runtime
- If battery gets low, the aGate drops non-essential loads (pool pump, EV charger, oven) to stretch runtime
The Hurricane Test
September 2025 — tropical storm brought 3 days of grid outage to our area. This time:
- Day 1: Overcast. Solar produced only ~12 kWh (vs. normal ~45 kWh). Battery carried us through the night running fridge, lights, fans, and one window AC unit.
- Day 2: Partly cloudy. Solar produced ~28 kWh — enough to recharge the battery and run the house. We even ran the central AC for a few hours.
- Day 3: Sunny. Full solar production recharged everything. Felt like a normal day.
No generator needed. No gas cans. No noise. Just quiet, continuous power.
Monthly Savings (Normal Operation)
The batteries also provide economic value day-to-day:
| Metric | Before Battery | After Battery | |---|:-:|:-:| | Solar self-consumption rate | ~45% | ~85% | | Monthly grid purchases | $40–$60 | $10–$25 | | Additional monthly savings | — | ~$45 |
The increased self-consumption (using stored solar instead of exporting cheap and buying expensive) adds approximately $45/month in savings on top of our existing solar savings.
Simple Payback
Battery economics alone: $45/month × 12 = $540/year savings → 33-year payback on $17,920. That's not great.
But the value isn't just economics. The peace of mind — knowing we can ride out multi-day outages without a generator — is worth a lot when you live in hurricane country. A whole-home generator installation would cost $12,000–$18,000 anyway, requires gas/propane delivery, maintenance, and testing.
Think of $5,000–$8,000 of the battery cost as "backup power insurance" and the remaining net cost as an economic investment. On that basis, the payback is more reasonable.
Advice for Battery Retrofit
- Whole-home vs. critical loads. We strongly recommend whole-home backup if budget allows. Having to choose which circuits to back up — and rewiring your panel — is expensive and limiting.
- Battery sizing for outages. In hurricane country, plan for 2+ days of cloudy weather. 20+ kWh capacity is the minimum for meaningful whole-home backup.
- Solar + battery together is key. Battery alone gives you one night of power. Battery + solar gives you indefinite backup (as long as the sun comes up).
- Check your solar system compatibility. Make sure your existing solar inverter/microinverters work with the battery option you choose.
- Insurance. Some insurers offer discounts for battery backup systems. Ask yours.