The Tahoe has two platforms for battery placement, one on the driver's
side in the front corner and the other on the passenger's side, just in
front of the firewall.  Our Tahoe uses the latter so our battery is on
the passenger's side.
The battery platform measures approximately 8 1/2" x 10 1/2"

The fuse box for the vehicle is located behind the battery platform on 
the driver's side.  In fact, the fuse box is actually between that battery
platform and the driver of the vehicle.  This vehicle has many fuses and
circuit breakers.  It can be accessed by removing the large black plastic
cover protecting the fuses.  The tray holding the fuses can be lifted to
provide access on the wiring side but raising the two gray pieces on each
end of the tray.  These gray lever handles are stored in a down position but,
when raised to the up and down position, allow the tray to be pulled up.
The gray handle on the front also covers two large studs.  These are actually
studs to allow power to the owner's accessories.  Standing in the front of
the vehicle and looking at the fuse box, the left stud is fused at 30 amps and
the right stud fused at 40 amps.  The fuses used are the small 5/8" square 
fused just behind the studs.

I've located two fuses which seem to be only powered when the ignition switch 
is on:  #42 (FWD) 15A and #46 (IPC) 10 A.