Switch wire for my Dual battery system

[Redboy]

Hi all,

My dual battery system consists of:
A relay, a solenoid, the batteries, a pull button switch.

When the relay gets closed, power goes to the solenoid, the solenoid joins the batteries.

All is good.

To close the relay, I used to have 2 options. One was to pull a pull button switch in the cab - effectively allowing me to jump start the car without getting out some jumper leads.

The other was a wire running from the back of my 2L altenator so the solenoid would join the batteries when the altenator was on (engine running).

With my new engine, 1UZ, this is not an option. So where can I connect the wire to ensure the solenoid joins the batteries only when the car is running? (the radio, etc, is out because I do not want them connected when key is on acc).

[Bluey]

could pick up 12v from the ignition run wire. this will only be at 12v when key is in run position. (same wire diesel guys tap into for their turbo timers)

[lexi]

I tapped into the charge light wire in alternator. Mine is Patrol. When you rev to put charge light out it feeds the relay.
Alex