Uploaded December 2025 | Updated September 2026, 1 week ago
Link to the calculator: cleversolarpower.com/dc-to-dc-charger-wire-and-fuse-calculator
š My Best-Selling book on Amazon: cleversolarpower.com/off-grid-solar-power-simplified
š Free Diagrams: cleversolarpower.com
In this video I explain how my DC-DC charger wire and fuse calculator works, and why I built it in the first place. I kept getting the same questions about wire gauge, fuse size, voltage drop, and āwill my battery still charge to 100%?āāso this calculator puts the math in one place and makes the decision process simple.
Youāll see the calculator on screen and Iāll walk through exactly what each input means, what the calculator is calculating in the background, and how to interpret the results. The goal is to help you size wiring thatās safe, avoids overheating, and doesnāt rely on guesswork.
Then I go through two real examples step-by-step: a 12V to 12V 30A DC-DC charger setup, and a 12V to 24V 15A DC-DC charger setup. I explain how the wire run length affects voltage drop, why the recommended wire size changes with distance, and how the fuse selection ties back to protecting the cable.
I also address a common worry with long wire runs: āIf I lose voltage in the cable, wonāt the battery never reach the target charging voltage?ā I explain why thatās not how charging works in practiceāvoltage drop is highest at full current, but as the battery fills up the current naturally tapers down, the voltage drop becomes much smaller, and the battery can still reach full charge.
Link to the calculator: cleversolarpower.com/dc-to-dc-charger-wire-and-fuse-calculator
š My Best-Selling book on Amazon: cleversolarpower.com/off-grid-solar-power-simplified
š Free Diagrams: cleversolarpower.com
In this video I explain how my DC-DC charger wire and fuse calculator works, and why I built it in the first place. I kept getting the same questions about wire gauge, fuse size, voltage drop, and āwill my battery still charge to 100%?āāso this calculator puts the math in one place and makes the decision process simple.
Youāll see the calculator on screen and Iāll walk through exactly what each input means, what the calculator is calculating in the background, and how to interpret the results. The goal is to help you size wiring thatās safe, avoids overheating, and doesnāt rely on guesswork.
Then I go through two real examples step-by-step: a 12V to 12V 30A DC-DC charger setup, and a 12V to 24V 15A DC-DC charger setup. I explain how the wire run length affects voltage drop, why the recommended wire size changes with distance, and how the fuse selection ties back to protecting the cable.
I also address a common worry with long wire runs: āIf I lose voltage in the cable, wonāt the battery never reach the target charging voltage?ā I explain why thatās not how charging works in practiceāvoltage drop is highest at full current, but as the battery fills up the current naturally tapers down, the voltage drop becomes much smaller, and the battery can still reach full charge.
