The Stovebolt Site Forums The Shop Area The Electrical Bay Connecting ammeter per instructions

Okay, Autometer says their ammeter I have does not need a shunt. Apparently built into the gauge.

According to instructions, connections on the gauge, one side goes to pos. battery, the other side to the alternator pos. To me, that's a dead short.

Because...The alternator pos. connects to a terminal on the fender, which has a wire connecting to the starter, which has a battery cable going to the pos. battery post. I know the gauge is in series. Since these are all basically the same point, why not go from the alternator pos. to the gauge, then from the other side of the gauge and back to the alternator pos.? Am I overthinking this?

Yes.

No current would flow in the loop you describe because both ends are the same place.

So...I can go from any battery positive point through the ammeter to any other positive point (I would use the alternator positive). I'm basically just trying to eliminate great distances of wire (at $1 a foot). And I'm thinking going from the starter positive.

Wiring an ammeter is ridiculously simple. It takes a huge amount of help to misunderstand it. Run one heavy wire (#8) from one ammeter post to the battery cable connector at the starter. Attach EVRTYTHING else- - - -ignition switch, power to the fuse block, headlights, AND the charging wire from the alternator to the other ammeter terminal. Absolutely NOTHING could be simpler. If the ammeter indicates backwards (- direction with the engine running) reverse the connections.
Jerry

The idea is that the ammeter (a meter) is to read the lack of charge or no lack of charge .......so......... battery hot to one terminal of ammeter, everything else, including alternator, to other terminal. (All on the ammeter or a terminal block for added space.)

Alternator output's main duty is to charge the battery when battery voltage is low enough to allow current to flow. When battery is up, the flow is "blocked"/"equalized". Of course the output is regulated and the rate is per speed of alternator shaft.

Basically you want to see the needle always on the plus side or middle. A lot when alternator is charging battery and a little when battery is up.. If it shows discharge that's when you start checking. Alternators are good at charging at fairly low RPM's. However starter motor will have drawn down battery for a short time.

It would seem very silly to sell an ammeter without a shunt. The ammeter reads the shunt. An ammeter is a giant buss bar with a tiny bypass circuit called a shunt.

Didn't see Jerry's post, so Pete and Repeat.

One tiny correction- - - -the purpose of a charging system is to provide power to everything- - - -ignition, lights, heater blower, sound system, etc. and then use whatever capacity is left over to recharge the battery. Most alternators are sized to carry the current demand of all the accessories, plus around a 25% over capacity for battery charging. Adding heavy current demand stuff without increasing the charging system capacity proportionally can lead to a chronically under charged battery from making up the added load.
Jerry

Okay, thanks everyone for the input, a lot more confident, just didn't want to burn up a $100 gauge.

So...are you saying that to connect everything else to the other post of the ammeter that, I need to hook into all the other connections you mentioned with a separate #10 fused link wire, or... that I can just run the wire to a post on the fusebox, or...just run the other wire to the alternator?

I understand the concept, just not the literal aspect of how to physically include all the other connections.

Most ammeters that are worth installing have one long stud that will accommodate several lug terminals. That also serves as a junction block so you don't need a complicated wiring harness. If you choose to add a bunch of unnecessary connection points, each one becomes a potential loose or corroded connection. I believe in the KISS principle for wiring- - - -it's worked for me for the past six decades, so I'm reluctant to do something different just for the sake of appearances. Very few people are going to go to the effort to stick their heads under the dash to admire the wiring.
Jerry

I'm not choosing to add any connections I don't have to. I'm merely trying to find out what/where I have to connect the 2nd/output wire from the ammeter so that I include all the points you mentioned. On one hand it sounds like you're telling me I have to run wires from all those points (ignition, power from the fuseblock, headlights, and alternator) to the ammeter, and on the other hand it's not necessary, keep it simple.

So again, my question is...Do I need to hook into all the other connections you mentioned with a separate #10 fused link wire, or... that I can just run the wire to a post on the fusebox, or...just run the other wire to the alternator?

Let's take this discussion to PM or a phone call- - - - -I spent 30+ years teaching automotive subjects, including electrical systems, to barely literate high school students from inner city ghettos, but not via the internet. A 2-way conversation is always better than a cyberspace keyboard battle.
Jerry

Tonerman, here is the kicker here. 1969 is little past our usual gig here. We do not have a wiring diagram for it. The 69 dash has either idiot light or an actual "battery" gauge. You seem to be adding an aftermarket ammeter. You chose not to replace whatever is in the cluster. The 1969 had moved to a more moduled approach with a printed circuit board on back of the gauges. Which has a connector and all the wiring harnesses to connect everything properly. Including the ammeter or idiot light.
You now know the general idea of an ammeter.

We don't know how you are going to connect the various wires from a printed circuit board and it's connector to you ammeter. That's up to you. In general most wires except for the 12ga from battery to ammeter, are per a wiring diagram. 20ga to 14ga. We don't know how you will connect other harness wires to the aftermarket ammeter. You know that almost everything should be feed from the ammeter. Probably should have done a volt meter. MUCH MORE SIMPLE IN YOUR CASE.

The ignition switch usually turns on some fuses in the fuse box and some fuses are "always hot". So many accessories will get power from the fuse panel. Ammeter to ignition, ign to fuse panel, if that is what the diagram says. Some things have a separate fuse/separate wire, maybe wiper, heater, light switch whatever. Just get them wired. Some things get direct power from the battery, your truck may feed battery power to the horn relay and use it as a "terminal block" to feed power to some things. light switch, ignition, etc.

You will need to refer to a 1969 C10 diagram or someone may post one here.

You know the plan, the hook up. Do it the best you can. Don't worry about how many connections or length. Everything is short under the dash anyway.

Is your alternator internally regulated or do you have a separate voltage regulator box?

Just to throw this in for the archives. When you see a negative symbol on the back of an ammeter (-)...It DOES NOT mean ground.

Well, I just connected one side to the starter solenoid and the other to the alternator. working as it should, showing charge and discharge. Thanks for your assistance.

Hi Bartamos; Thank you for your input. After a week of asking questions and many Youtube videos, I believe I got a sense of how this electrical system works. Needless to say, many hands had been at the wiring before I got the truck years ago and wire colors are not consistent. Also, this being a basic dash with just speedometer and gas gauge with idiot lights for the rest, I have been improvising the instrument cluster and new bezel to accommodate my aftermarket Autometer gauges and sensors along with the current instrument cluster circuit board.

Somewhere along the years I acquired (in a $5 box of parts) this set of Autometer gauges, all working, and worth $300 I've found out, so that included the ammeter and the main reason I'm using it along with the electric temp and oil gauges. I've consulted with Autometer and found out the correct oil and temp sensors and that this ammeter did not need a shunt.

I finally connected the ammeter, one side to the starter solenoid and the other to the alternator, and in testing, it is working as it should. I do have a separate voltage regulator next to the horns by the radiator. Not sure how this plays into it, but, the ammeter is working. I'm wondering if I should make a fused link in each wire?

I've also installed a tach into the dash bezel which is also working properly. But, this created another obstacle because that is where the directional indicator lights were for the current instrument cluster board. The new bezel has the light openings further away so they won't work where they are. Could be I'll still have to get a new instrument cluster board.

All this, just because I bought a new shiny bezel.

Soon you will be answering questions on other posts regarding these issues for others to learn from you.. Good job. I salute your efforts and determination.