Find the right charge controller size (MPPT or PWM) for your solar panel setup.
Controller Amps = Solar Watts ÷ Battery Voltage
Example: 400W solar ÷ 12V = 33.3A → 40A controller
Rule of thumb: Add 25% safety margin. A 400W system needs a 40A controller minimum.
| Feature | MPPT Controller | PWM Controller |
|---|---|---|
| Efficiency | 95-99% | 75-85% |
| Best for | 400W+ systems, cold climates | Under 200W, budget builds |
| Cost | $80-300 | $20-50 |
| Voltage handling | High Voc (up to 150V) | Must match battery voltage |
| Recommendation | MPPT is worth the extra cost for most van builds | |
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