Comparing Battery Technologies in Solar Lighting

The battery determines runtime, lifespan, and cold-weather performance. Here’s how technologies compare.

Lithium-ion (18650 cells):

Capacity: 2000-3500mAh per cell

Cycles: 500-800 to 80% capacity

Temperature: 32°F to 113°F optimal

Cost: $5-8 per cell

Best for: Most residential applications

Lithium Iron Phosphate (LiFePO4):

Capacity: 1000-1500mAh per cell

Cycles: 2000-3000 to 80% capacity

Temperature: -4°F to 140°F operational

Cost: $10-15 per cell

Best for: Extreme climates, commercial use

Nickel-Metal Hydride (NiMH):

Capacity: 2000-2500mAh per cell

Cycles: 300-500 to 50% capacity

Temperature: -4°F to 122°F operational

Cost: $3-5 per cell

Best for: Budget applications, warm climates

Lead Acid (SLA):

Capacity: 2000-8000mAh

Cycles: 200-300 to 50% capacity

Temperature: -40°F to 122°F operational

Cost: $15-40 per battery

Best for: High capacity needs, cost-sensitive

Performance comparison table:

Technology Cycles Cold Performance Cost/Cycle
LiFePO4 2000+ Excellent $0.005
Li-ion 700 Good $0.007
NiMH 400 Fair $0.008
SLA 250 Excellent $0.060
Selection guidelines:

Residential moderate climate: Li-ion

Extreme cold/hot: LiFePO4

Budget projects: NiMH

High capacity stationary: SLA