12 volt resistor relay

Can anyone tell me exactly how a 12 volt resistor relay works?  I need a relay that will supply 12 volts and not increase to 14+ volts with the alternator charging the circuit.  Thanks for your support, Tommy.

You need a 12V voltage regulator.

Do you know what type of voltage regulator?  I remember the old type from the 50's and 60's, is that the type you are referring to?  How about a part number and brand?  Thanks for your support, Tommy.

Typically 12vdc voltage regulators require about 2vdc of headroom, meaning you would need an input of greater then ~14vdc to insure correct output.  What are you trying to acomplish?

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Kevin Pierson

I'm working on a drivetrain conversion.  I installed a Chevy 3.8 V-6 into my 2002 PT Cruiser.  Due to electrical overloading on two relays, I fabricated a power distribution panel.  This new distribution panel now takes care of my fuel injectors, ignition control module and 02 sensors which were previously hooked up to the two overloaded relays.  The new distribution panel is feed directly from the battery.  The power runs to a distribution block, from there it runs to 3 breakers, from there it runs to 3 relays up to pin terminal 30.  The ignition switch then activates the relay contacts and the power then runs individually to a fuse block.  Each of the 3 circuits mentioned above has it's own breaker, relay and fuse.  Here is where the problem starts.  When the engine is running and the alternator is charging, the 3 circuits that are getting feed, is receiving whatever voltage that the alternator is putting out, which is just over 14 volts.  That's why I need something that will keep the voltage at 12 volts.  Hope this helps, Tommy.

A quick search on the Radio Shack website will land you with a few voltage regulators, however as previously stated some headroom will be required to ensure a stable output. Also note, that many voltage regulators can only supply about 1A of output current; likely less than you are needing. How much current are you needing to supply?

Rather than just being able to plug in a simple device, you will likely have to build a circuit to supply your needs.

The circuits require a 10 amp, 15 amp and 20 amp fuses.  The only thing I can think of using would be that old style regulator boxes from the 50's and 60's.  Not sure how they work though?  Does anyone know?  Thank you,Tommy.

It is 'normal' for all these circuits to get ~14.7VDC.  Your injectors, coils, and O2 sensors are designed to run off of alternator voltage.  Your 'stock ignition' wire is 14.7vdc when the car is running.

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Kevin Pierson

KPierson, I wasn't sure if that amount of voltage would damage the injectors, the ignition control module or the 02 sensors.  So, base on what you said, I really don't need to make any other modifications.  Thank you for your support, Tommy.

Nope, they will all be fine, they are designed to operate that way (assuming all the components are modern day 12vdc components and you don't have any 6vdc stuff in the mix!)

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Kevin Pierson

KPierson, awesome!  Yes, I don't have any 6 volt items in the distribution panel.  If you like you can email me at this email address: Chevyone@hawaii.rr.com  I'll send you pictures of the power distribution panel and engine compartment.  Thanks again, Tommy.