Short answer: About 300–400 W of solar refills an empty 12 V 100 Ah lithium battery in one day with 4–5 peak sun hours. A single 200 W panel takes about two days.
100 Ah × 12.8 V = 1,280 Wh. Divide by sun hours × 0.75 efficiency:
| Peak sun hours | Solar for 1-day refill (lithium) | AGM (50% refill) |
|---|---|---|
| 3 | 569 W | 284 W |
| 4 | 427 W | 213 W |
| 5 | 341 W | 171 W |
| 6 | 284 W | 142 W |
Use the solar charge time calculator for your setup.
Safety: These are general estimates, not a design. Follow your equipment manufacturer's instructions and local electrical code, and consult a qualified electrician for anything connected to shore power, a house, or high-current batteries.
Yes, slowly: about 17 peak-sun hours from empty, so 3–5 days. It's fine for maintaining a battery or covering light daily use.
A 48 V 100 Ah battery holds about 5,120 Wh, so roughly 1,300–1,500 W for a one-day refill at 4.5–5 sun hours.
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