Hooking up many relays

[A70Runner]

I am going to be hooking up a few relays on my car. Headlights, Radiator Fans,Fuel Pump, and probably a fan on the Trans cooler. Two questions. Where is everyone hooking to ( I know not the battery) and is anyone using a central add on hookup point?

Hope this makes sense.

Thanks!
A70

 

[rmchrgr]

I would suggest using an MSD solid state relay. It has provisions for four devices and is run off one power wire. The triggers can be on the power or ground side. Yes, it's a bit pricey but it will save you a lot of hassle. I use them, they are a nice product.

MSD Solid State Relay

On the fans and trans cooler you'll need thermostatic switches to trigger the relays.

 

[radical rob]

Either that or a small separate fuse block fed directly from the battery, that would let you fuse each circuit

 

[Sixpactogo]

I fed my fan and headlight relays with a #8 wire off of the Alternator stud. Been working fine for 6 years.

 

[RJRENTON]

I am going to be hooking up a few relays on my car. Headlights, Radiator Fans,Fuel Pump, and probably a fan on the Trans cooler. Two questions. Where is everyone hooking to ( I know not the battery) and is anyone using a central add on hookup point?

Hope this makes sense.

Thanks!
A70

When I learned electrical system components, there were two types. IEC International Electrotechnical Commission (IEC) for electrical relays, focusing on functionality, safety, and performance. And NEMA (National Electrical Manufacturing Association). The trend now is to use the light weight IEC components or the industrial NEMA rated stuff. The IEC stuff is maximum amperage/time rated where as the NEMA components are horsepower rated. My preference is the NEMA stuff as it's heavy duty and the IEC stuff looks very light duty rated. There is a significant night and day difference between the two types, with the IEC stuff is cheaper. Just my opinion.....circuit design differences are similar but maximum amperage ratings are different, especially with relays...Both types are available on line and thru ebay...
BOB RENTON

 

[gkent]

The solid state are nice but this one allows relay and fuse replacement

 

[T2R9]

The solid state are nice but this one allows relay and fuse replacement

View attachment 1898428

This is the one I use. Very nice setup.

 

[72RoadrunnerGTX]

If running a stock ammeter-based charging system, never connect loads at the battery or anywhere on the battery side of the ammeter. If not wanting to connect directly at the alternator stud, you can use a simple stud mount near the bulkhead connector, land the alternator feed on it and run another wire through a grommet to the ammeter, by passing the troublesome Packard bulkhead terminal for the alternator to ammeter feed. Load placement matters.

Alternatively, you can use a stud passthrough and connect the new alternator feed from inside of the firewall. Both approaches require a hole in the firewall be created.

 

[Crackedback]

On OEM ammeter wired cars... With items that run in both engine on or engine off state, there is no perfect place to pull power. You have to make a choice and go with the pickup point that the accessory will run most of the time, usually engine running.

 

[72RoadrunnerGTX]

Of the items listed by the OP in the first post, which would you consider would not be in use most of the time while the vehicle is in operation, engine running? Other than convertible top pumps and station wagon rear gate windows, what other types of accessories are you referring to that would be better prioritized for operation while the vehicle is at rest, engine not running?

 

[gkent]

Other than those which are "factory wired", the only things I can think of that would need full-time power would be the fan(s) and waterpump (if electric). Everything else would be run off "keyed power". That said, it doesn't mean that other accessories need to be run through the ammeter. You can use relays connected to full-time power but triggered by the "key on" power. The relays draw next to nothing and are not a significant load through the ammeter.