[oil pan 4]

After an hour of very cool bum the ice melted.
I put almost a gallon of room temperature water in the bottom to start off the cycle then put around 3 or 4 pounds of ice in there.
The lines running to and from the cooler were uncovered too, collecting condensation and I ran the pump constantly. This adding additional heat to the ice.
So the ice lasts longer than I thought it would.
With efficiency add ons like covering the exposed lines and cycling the pump the ice should last even longer.

Toward the last of the ice I tried cycling the pump on and off.
To swap the warm water out for cold through 20 feet of line takes maybe 10 seconds. Then stays cool for around 2 to 3 minutes.
A live well pump timer runs 30 seconds on then stays off up to 5 minutes.
So the live well timer I was thinking about using should be perfect.

My amp meter says the pump draws a little under 2 amps at 11 volts (the jump pack is getting low on power).
If we say the pump runs for 30 seconds then stays off for say 90 seconds.
At most its only average of a half amp.
Even 30 seconds on, 30 off is 1 amp average, so it will work well with an alt delete. It will use a fraction of the power of the A/C where you need a few amps to energize the magnetic compressor clutch, then 10 to 20 amps to run the blower fan.

The numbers say it should work well, in practice it works a lot better than I ever expected.
I am not often surprised like this.