Solar Batteries: The Basics
Solar batteries store excess energy from your panels for later use. Instead of sending extra power to the grid, you save it to use at night, during outages, or when electricity rates are highest.
How Solar Batteries Work
- Morning: Solar panels start producing, powering your home directly
- Midday: Production exceeds use - excess charges the battery
- Battery full: Once charged, excess goes to grid (if grid-tied)
- Evening: Solar production drops - battery powers your home
- Night: Battery continues powering home until depleted
- Grid backup: If battery depletes, grid takes over (if connected)
Types of Battery Systems
- AC-coupled: Battery connects to your home's AC electrical system. Can be added to existing solar. More flexible but slightly less efficient.
- DC-coupled: Battery connects directly to solar panels before inverter. More efficient but requires compatible inverter.
- Hybrid inverters: Single inverter handles both solar and battery. Cleanest installation for new systems.
Do You Need a Battery?
The honest answer: most grid-tied homes don't need batteries. Here's when they make sense - and when they don't.
You Probably DON'T Need a Battery If:
- You have good net metering - Saskatchewan's full retail rate net metering means the grid is a free, infinite "battery"
- Power outages are rare - If you lose power once or twice a year for a few hours, a battery's cost doesn't justify the backup
- Your budget is limited - Batteries add $8,000-$20,000+. That money could buy more panels or go toward other priorities
- You don't have critical loads - If you can manage without power for short periods, backup isn't essential
A Battery MAKES SENSE If:
- You experience frequent outages - Rural areas with unreliable power benefit most
- You have medical equipment - CPAP, oxygen concentrators, or refrigerated medications need reliable power
- You work from home - Power outages mean lost income
- Your utility has time-of-use rates - Store cheap solar power, use when rates are high
- Net metering is poor - Some utilities pay less for exports than you pay for imports
- You want energy independence - The peace of mind of reduced grid reliance
Saskatchewan Reality Check
With SaskPower's excellent net metering (full retail rate), batteries rarely make financial sense in Saskatchewan purely for savings. The main reasons to add a battery are backup power and energy independence - not economics.
Battery Costs
Upfront Costs (Installed)
| Capacity | Typical Cost | Cost per kWh |
|---|
| 5 kWh (small) | $6,000-$9,000 | $1,200-$1,800 |
| 10 kWh (medium) | $10,000-$14,000 | $1,000-$1,400 |
| 13-15 kWh (large) | $12,000-$18,000 | $900-$1,200 |
| 20+ kWh (whole home) | $18,000-$30,000+ | $900-$1,500 |
Financial Payback
Battery economics depend heavily on your situation:
- With good net metering: Often never pays back financially (value is in backup)
- With time-of-use rates: 10-15+ year payback typical
- With poor net metering: 8-12 year payback possible
- Off-grid: Essential - no payback calculation needed
Warranty & Lifespan
- Warranty: Most quality batteries have 10-year warranties
- Lifespan: Expect 10-15 years of useful life
- Degradation: Batteries lose ~2-3% capacity per year
- Cycles: Most rated for 4,000-6,000 charge cycles
Popular Battery Options
Tesla Powerwall 3
- Capacity: 13.5 kWh
- Output: 11.5 kW continuous
- Features: Integrated inverter, excellent app, whole-home backup capable
- Price: $12,000-$15,000 installed
- Best for: Whole-home backup, Tesla ecosystem users
Enphase IQ Battery
- Capacity: 3.4 kWh or 10.5 kWh units (stackable)
- Output: 3.84 kW per unit
- Features: Modular, works great with Enphase microinverters
- Price: $8,000-$16,000 installed
- Best for: Homes with Enphase microinverters
Generac PWRcell
- Capacity: 9-18 kWh (modular)
- Output: Up to 9 kW
- Features: Scalable, good for varying needs
- Price: $15,000-$25,000 installed
- Best for: Customers who want expandability
LG RESU
- Capacity: 9.6-16 kWh
- Output: 5-7 kW
- Features: Compact, reliable, good track record
- Price: $10,000-$15,000 installed
- Best for: Reliable backup without premium pricing
Sizing Your Battery
Step 1: Define Your Goal
- Essential backup: Fridge, lights, a few outlets, WiFi - 5-10 kWh
- Extended backup: Above plus some appliances - 10-15 kWh
- Whole home backup: Everything including HVAC - 20+ kWh or multiple batteries
Step 2: Calculate Your Loads
| Appliance | Watts | Hours/Day | kWh/Day |
|---|
| Refrigerator | 150 | 8 | 1.2 |
| LED Lights (10) | 100 | 6 | 0.6 |
| WiFi Router | 15 | 24 | 0.4 |
| Phone/Laptop Charging | 50 | 4 | 0.2 |
| Furnace Fan | 500 | 8 | 4.0 |
| Essential Load Total | ~6.4 kWh |
Step 3: Add Buffer
Multiply your daily essential load by 1.5-2x for realistic sizing. Batteries shouldn't be fully discharged, and you want reserves for unexpected needs.
Example Sizing
6.4 kWh essential daily load x 1.5 buffer = ~10 kWh minimum battery size for one day of essential backup. A 13 kWh battery would give comfortable margin.