center zero ammeter

G'day. I do a wee bit of electrical installation for mates. I have a Trisco G1101 Center-Zero ammeter, as does a mate. My question is this: The instructions for it have 3 different methods for installation- 1 For cars with magnetic starter switch 2 For cars with a seperate, or horn relay, mounted junction terminal 3 For cars with the starter solenoid mounted directly on the starter Which set do I use for a 1989 Nissan Sentra and a 1996 Mazda Lantis? I'm guessing no. 3 for my Sentra? Also what gauge wire? Will 10 be ok or do I need to go to 12? Cheers Falcon

Heres a link to an auction site with a pic of the unit. It doesn't say anything about a shunt but says "To install the ammeter correctly requires that all the added wiring be the same gauge or larger as the wire originally found on the car(typically #10 or #12 AWG" This makes me think it has an internal shunt as it requires same gauge. Judgeing by the diagram method no 1 is in series with starter, no 2 is in series with horn relay and no 3 is in series with starter

I would not connect it in series with the starter.  What are you trying to monitor, The output of the alternator, or powe concumed by an amplifier?Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

In the Lantis I want to be meausuring consumption of amp and charge of battery. In Sentra I want to measure charge/discharge of battery.

In both cases, between the battery and the alternator will be the best spot.  However 60 amps is probably lower than the alternator is rated at.  If you see that the meter is consistently running near the edge of it's limit, you may need to add a jumper wire across the shunt of the meter, and just use it as a reference so you will know if it is charging or not.  The jumper will make the meter inaccurate.  But it will be better than melting the shunt out of the meter.Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB