How does the MPPT calculator work?
This calculator helps you choose the right MPPT (Maximum Power Point Tracking) charge controller for your solar panel setup.
Frequently asked questions
Why the 1.15 cold weather factor?
Solar panel Voc increases as temperature decreases. On a cold winter morning with full sun, voltage can be 10-15% higher than rated. Exceeding the controller's max input voltage can permanently damage it.
Series or parallel — which is better?
Series increases voltage (higher efficiency, thinner cables) but requires a controller with higher voltage rating. Parallel keeps voltage low but increases current. For most camper setups with 2-4 panels, series is preferred on a 12V system.
What if I need more panels than the controller can handle?
You can use multiple MPPT controllers, each with its own panel group. This also provides redundancy — if one controller fails, the other still charges.
Can I combine panels from different brands?
In series, panels must be identical (same current). In parallel they can differ in current but must have the same voltage. When in doubt: use one panel type.
What happens if my MPPT is too small?
The MPPT limits current to its maximum. You lose the excess power, but nothing breaks. It does waste your panel investment though.