Need to make a timed relay.

[quad]

Anyone got any ideas on how to make a relay hold 1-2 minutes after the ignitions is switched off. I've looked at using the flexitimer KA1732,
my idea would not to rely on a constant Voltage and a 12+ trigger.
I want to use this in my ute for my dual battery setup. I have a Solonoid Isolator activates when the car is started and deactivates when the car is turned off, but I want the solonoid to keep the two batteries contected for a couple of miniutes after the car is turned off.
I was thinking maybe the trigger 12+ could charge a capacitor which would then supply 12+ to the relay and hold it closed till it drained.

[Godzilla]

You could just buy a cheap turbo timer, dial in the time you want like 1 to 5 minutes and connect it to a relay to do what you want.

The good thing is you can turn it off or dial in what ever time you want as you feel you need.

Just wire it in not to run the engine but rather keep your relay active.

[watchdog]

A simple NE555 timer will do what you want. Google for circuits or give me a pm

[FTO King]

couple of ways, for maximum flexibility, use a micro controller embedded system it will require programming though.

If programming is not an option, a simple count down timer will do the trick.

[ecu-man]

use a Pixaxe 08M chip

[Chloe]

What do you want actual Ne555 timer you have already if you have ok so now you want google circuits we will share soon pm

[quad]

Thanks for the responses guys, At the moment I'll look into the turbo timer option as I already have one connected.
I was throwing the question in the hope that it would be possible to run with the relay via storing a charge that would hold the relay open, The reason I wanted to do this was so I won't have a supply voltage, just a trigger been the ACC that would charge the storage and when the engine was switched off it would slowly drain finally dropping the relay.
From the responses I have recieved this option can't be achieved?