This one is for the Electrically Gifted

[Loren Beach]

The factory engine panel on our boat has the 60 - 0 -60 ammeter and it does really indicate amps in 'n' out.
I recall that one time when starting after two days of hard fridge use in a 90 deg. summer it dropped to under 11 for an instant when turning over the starter motor, and engine fired right up.
After an event like that it will often show a 30 amp charge for a few minutes, but that tapers down fairly quickly to 5 or 10.
Anytime I energize the glow plug circuit it shows quite a minus for the 15 seconds the button is held.

I thought they all did this.

Edit: our instrument panel (and others I have seen on Ericsons) only has a Universal label on it with no mention of Ericson yachts. I am almost sorta kinda sure that the panels I have observed on Catalinas have the Catalina Yachts logo on them.
Perhaps Catalina specified their own panel gauge and switch layout, being as they were ordering up so many at a time. (?)

 

[Emerald]

Think of volts as water pressure, and amps as water flow or even the diameter of the pipe carrying the water (and hence changing flow rates for a given pressure or voltage) So when the amp meter is showing a big negative, while operating the glow plugs or getting that beer cold, it's showing the flow (current), not the pressure (voltage). Here's a nice little write up I found that does a pretty good job of relating the basics on simple electricity concepts:

http://elf.torek.net/torek/elec/basics.html

 

[Tom Metzger]

If you make the changes that I recommended you have run the alternator output to the solenoid which is connected to the battery with large wire - likely 1/0 through the 1-2-both switch. This means that the only current that goes to the engine panel is the engine operating current - fuel pump, glow plugs, instruments, and blower.

If you don't make these changes all alternator current goes through the ammeter on the engine panel and the meter can read + or -, depending on alternator output.

 

[Stu Jackson]

It's interesting that our boats may have come with different ammeters than the 0-60-0 ones you have installed. I didn't actually see the ammeter that was originally installed on our boat 'cuz the PO had removed it before our purchase. Except for the large starter draw mentioned, the relatively small amperages that our boats normally see, 10 to 15 even with a fridge running, maybe 20 with running lights and a fridge, will hardly even register on those ammeters. I do not know, and would like to learn, if they have internal or external shunts, and how they're wired.

 

[Tom Metzger]

Stu - The shunt is "internal", but it could possibly be mounted on the meter's studs - I don't remember and have no pics. Teleflex's catalog gives no indication that it is external.

Why would you expect anything unusual about the wiring? A standard center zero meter movement with a shunt across its terminals.

The starter current does not go through the meter. The starter is wired through the solenoid to the battery.

FWIW, on my son's PS/E-333 a 50 amp ammeter on the AC/DC panel has an external shunt, but I can't remember if it was the AC or the DC meter, or both. Which ever it was, I fixed the bad connection and it worked again.