What are the consequences of jump-starting a 12V car with 24V?

[LeJade]

There are multiple potential risks including excessive heat generation during charging, wiring burnout, charger damage, and battery failure. To safely charge a 12V system with 24V, several conditions must be met: 1. Avoid direct charging: Generally not recommended unless the 24V charger has built-in current-limiting and voltage-stabilizing control circuits. 2. Circuit modification required: If the charger lacks these features, you'll need to modify the wiring yourself, which requires hands-on skills and electrical knowledge. Battery charging requires constant-current/constant-voltage external charging equipment (like a proper charger). Without relevant control circuits, you may achieve similar results by adding external rectifier circuits (such as bridge rectifiers) at the output end.