I plan on installing a radio shack SPDT or DPDT Bosche relay on a possible low voltage source.

What is the minimum voltage/power necessary to activate a typical relay ?

I will be using it to activate and de activate the fuel pump...

X2

 

Tough to say. Hook up the relay in question to a variable power supply, and increase the voltage until you hear it click. There you go.

The catch is, relays are heat sensitive. The hotter the relay is, the hotter the copper wire is, which increases its resistance, which means you need more voltage to activate it...

 

dude, if you find out, please let me know!!

 

Why dont you just got a heavy duty DC switch and use smaller gauge wire than the stock power line running to the fuel pump?

 

Not sure if this is helpful or not:

30 Amp Automotive Relay

DPDT 10 Amp 12V

 

most automotive relays require at the bare minimum of at least 10v to operate and even at 10v, it could be sketchy. anything below that might work, but prolonged use would cause it to "pulse"

 

This is why I need it.
I am putting in a relay for a fuel pump kill switch and of course don't want to use an inline switch. I want a relay'd switch for obvious reasons, but want to ensure the relay will stay engaged while powered and not shut off... I used to use a relay for my 12v in car neon w/o a hitch (flame if you want ) But want to make sure, cuz don't want the fuel pump to die on me.

Anyone else done a relay to kill the fuel pump ? Any probs w/ it ?

X2