How Do I Calculate the Size of the Off-Grid Solar System I Need?

If you’re thinking about going off-grid in Columbus or anywhere in Central Ohio, getting the size of your solar system right isn’t just important — it’s essential.

At BC Solar, we take a practical, no-nonsense approach to sizing your off-grid solar setup. Here's how we do it.

Step 1: We Start With Your Real Usage

Your energy habits are the foundation. We review:

• Your daily electricity use (in kilowatt-hours)

• Seasonal differences (more lights and heat in winter? more AC in summer?)

• Peak appliance loads (well pump, fridge, HVAC, etc.)

We’ll usually look at 12 months of electric bills or use a detailed load calculator if you’re building off-grid from scratch.

Step 2: Then We Assess Solar Access and Space

Solar panels need sunlight — but they also need space.

• Got a sunny, shade-free roof? Great.

• Need a ground-mount system? We’ll measure and plan accordingly.

• Live in the woods or have winter shading? That’ll impact panel count and battery needs.

Step 3: Battery Storage is Your Lifeline

Unlike grid-tied systems, an off-grid setup must store enough energy to cover:

• Overnight power needs

• Cloudy day deficits

• Backup for storms or extreme weather

We don’t cut corners here. In fact, we design with buffer capacity — because running out of power isn't an option.

“Overbuilt is better than undersupplied. It’s your lifeline.” — Brian Zaayer, Owner of BC Solar

Step 4: Backup and Redundancy Options

We may recommend:

• A generator (manual or auto-start)

• Hybrid inverter with smart switching

• Additional battery capacity for winter

Every system we install is custom, with safety and long-term resilience at the core.

FAQs

How much battery storage do I need for off-grid solar in Ohio?
It depends on your daily usage and how many “days of autonomy” you want. We usually recommend 2-3 days of stored energy as a minimum. For example, if you use 15 kWh/day, a 45 kWh battery bank is a solid baseline.

Can I run off-grid solar without a backup generator?
You can, but we don’t recommend it — especially in Ohio’s cloudy winters. A generator adds critical redundancy and helps recharge batteries faster in emergencies.

What if I already have solar panels — can I go off-grid?
It’s possible, but your existing system may need upgrades. Most grid-tied panels aren’t designed for battery backup or full disconnection. We can assess and retrofit if it makes sense.

Ready to get serious about energy independence?

Let’s talk about what your home really needs — no guesswork, just honest numbers.

📞 Call BC Solar at (614) 442-9700
📍 Visit us at 777 Busch Ct, Columbus, OH
🌐 Learn more at https://bc.solar