Ammeter Overcharging

[fastd]

Patrickt,

I’ve done this upgrade on other cars (without ammeters) with the goal of reducing power through the switch AND taking power directly from the battery to the headlights. I am getting a little confused about how to think about the wiring if the power stills comes through the fuse box. The trigger wire still run off of fuses 7 & 8 for my 289fia...is it still ok to take power for the relay from fuse 7 or 8 to power the relay/headlights.
Life might be easier and simpler if I take the ammeter out.

[patrickt]

Originally Posted by fastd

Patrickt,

I’ve done this upgrade on other cars (without ammeters) with the goal of reducing power through the switch AND taking power directly from the battery to the headlights. I am getting a little confused about how to think about the wiring if the power stills comes through the fuse box. The trigger wire still run off of fuses 7 & 8 for my 289fia...is it still ok to take power for the relay from fuse 7 or 8 to power the relay/headlights.
Life might be easier and simpler if I take the ammeter out.

That's just a case of confusing verbiage. We are not running through the fuse box. When someone says "take the power off the fuse box" that doesn't necessarily mean the fused side of one of the fuses, rather it refers to a nice easy convenient feed that is usually half way between the alternator and the battery. If you are staring at the two ERA fuse boxes, the one on the passenger side of the car is the first box. The top fuse of that box, on the passenger side of the fuse, is a direct feed from the alternator (and the fused side of that fuse runs to the fans). If you just tap that passenger side screw, it will always be hot, and it is unfused. So, whatever you run from a tap from that screw must have an inline fuse, or circuit breaker, to protect it. That's all the phrase means.

[patrickt]

Here, either of these two screws (if you look closely you will see they are connected to one another by a metal strip) is a nice, convenient tap for power that is both un-fused and is "coming off the fuse box." It is always hot, and it is my preferred tap for stuff. You must supply a fuse or circuit breaker for any line you take off it (headlights, fuel pump, rocket launcher, etc.)

[Gaz64]

Originally Posted by patrickt

That's just a case of confusing verbiage. We are not running through the fuse box. When someone says "take the power off the fuse box" that doesn't necessarily mean the fused side of one of the fuses, rather it refers to a nice easy convenient feed that is usually half way between the alternator and the battery. If you are staring at the two ERA fuse boxes, the one on the passenger side of the car is the first box. The top fuse of that box, on the passenger side of the fuse, is a direct feed from the alternator (and the fused side of that fuse runs to the fans). If you just tap that passenger side screw, it will always be hot, and it is unfused. So, whatever you run from a tap from that screw must have an inline fuse, or circuit breaker, to protect it. That's all the phrase means.

Fantastic others understand this.

Keep up the good work, as always, Pat.

[Anthony]

Originally Posted by fastd

Life might be easier and simpler if I take the ammeter out.

Well, I don’t know.

Maybe it would depend if and what the maximum continuous rating is for the ammeter? I mean if the gauge will read 60 amps , but it’s only rated for up to 40 amps continuous, then I would think keeping the amps under 40 would be safe/ fine. In my experience, I’ve burned up a lot of things, but I’ve yet to have burned up an ammeter.

Do these ammeters have ratings?

[fastd]

Anthony,

I'm not giving up on my ammeter for the moment; right now it shows about 7 amps cause I have my efi ecu hooked straight to the battery.

But since patrickt pointed out that fuses #1 and #2 are direct, unfused from the alternator, I can take my power for the highlight relay upgrade from there without confusing myself (or adding more amps across my ammeter)...my ammeter lives to fight another day.

[fastd]

Originally Posted by patrickt

Here, either of these two screws (if you look closely you will see they are connected to one another by a metal strip) is a nice, convenient tap for power that is both un-fused and is "coming off the fuse box." It is always hot, and it is my preferred tap for stuff. You must supply a fuse or circuit breaker for any line you take off it (headlights, fuel pump, rocket launcher, etc.)

Super good! thanks again.

[fastd]

Originally Posted by fastd

Really the volts don’t get in the 14s. Stays pretty close to 13.4. Do you agree with Anthony (thanks Anthony btw)

After actually checking - my voltage range is about 13.8-14.1