The switch mentioned above takes 10A at 125V (DC I assume?)
10 x 125 =1250W
1250W / 24V = 52A
Wrong reasoning. The switch capacity is not determined by the power but by the current.
The problem is arcing
when the switch opens. The switch rating is 10 A @ 125 V and is valid for AC. When a switch for AC opens he contacts, the air gap between the opening contacts will become ionized and current will continue to flow between the contacts. As the ionized gas has a comparatively high resistance, lots of power is being dissipated and the contacts can melt. With AC this problem is solved as with every zero crossing of the AC current the electric arc is interrupted giving the air a chance to cool down while the contacts open further until they reach the end position. Thus the arc is extinguished, no current flows, no power is dissipated.
With DC there is no zero crossing of the current. The arc may be sustained and the contacts can burn away. This can be solved by one of two methods:
- A wider gap between open contacts. A wider gap will eventually lead to a breakdown of the electric arc and the current will stop.
- An additional blowout magnet within the switch placed directly next to the contacts. This magnet creates a magnetic field which in turn will push away the arc from the contacts, thus lenghtening the path and quenching (extinguishing) the arc.
It is not uncommon that a switch can, for example, operate 1000 W with AC but only around 30 W with DC.
I second the recommendation by @kellys_eye
to use an automotive relay. These are made to handle high current at 12 V DC.