400W Solar Panel Output - How Much Power?
A 400W solar array is the sweet spot for serious mobile living. It provides enough power for a fridge, regular laptop use, lighting, and occasional high-power devices. Expect 1600-2000Wh per day in good conditions.
Rated Power
400W
Daily Output (Summer)
2000Wh
Voltage (Vmp)
40V
Typical Use
Full-time van life
Output Calculator
Your Battery (for charging estimate)
Daily Production
1700Wh
Peak Output
340W
Charge from 50%
1.8 hrs
Charge from Empty
3.5 hrs
Recommendations
* Actual output varies by location, season, panel angle, and shading.
400W Panel Output by Conditions
| Conditions | Peak Output | Daily Production |
|---|---|---|
| Full sun (summer) | 400W | 2000Wh |
| Partial sun | 240W | 1200Wh |
| Winter / cloudy | 160W | 800Wh |
| Overcast | 80W | 400Wh |
* Based on typical conditions. Actual output varies by location, angle, and temperature.
Battery Charging Times
| Battery Size | Voltage | Time to Full Charge |
|---|---|---|
| 200Ah | 12V | 8 hours |
| 300Ah | 12V | 11 hours |
| 400Ah | 12V | 15 hours |
* From 50% to full in ideal sun conditions. Charging slows as battery approaches full.
- ✓Full-time van life
- ✓Extended RV trips
- ✓Small off-grid cabin
- ✓Liveaboard boats
- ✓Serious preppers
- ✗Running AC regularly
- ✗Electric cooking
- ✗Off-grid homes with normal appliances
400W Solar Panel Tips
- •The comfortable minimum for full-time van/RV living
- •Can fully recharge a 200Ah battery bank daily
- •Requires 30-40A MPPT charge controller
- •Consider wiring panels in series for higher voltage (less current, thinner wires)
- •Leaves headroom for cloudy days and winter
Panel Specifications
Typical Dimensions
4x 100W or 2x 200W panels
Weight
50-70 lbs total
Voltage at Max Power (Vmp)
40V
Current at Max Power (Imp)
10A
Frequently Asked Questions
Is 400W solar enough for off-grid?
For a van or small RV with efficient 12V appliances, yes. For a cabin or larger RV, you likely need 600W+. It depends entirely on your consumption.
What battery size for 400W solar?
200-300Ah of LiFePO4 pairs well with 400W. This gives you 2-3 days of autonomy during cloudy weather while still being able to fully recharge on good days.
How many solar panels is 400W?
Typically 4x 100W panels or 2x 200W panels. Four 100W panels often fit roofs better and provide redundancy if one panel is shaded.