I'd be reluctant to use something like that when there are purpose-built switches available for the job. Automotive DC electrical systems carry more amperage than any household circuit, even considering the voltage difference. DC systems are just different, and even a fraction of an ohm of resistance in the wrong place can cause problems. J.C Whitney, and several other mail-order or online parts dealers have cutoff switches that are drsigned to work with an automotive system.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!