Do you ever get a static shock off the car when you touch it?
A bad connection on the battery will not give you a static electricity shock.
When I get one, it tends to be related to what I am wearing. Any man made fabrics on man made seats will create static.
Always worse on warm dry days.
The car moving through dry air, and tyres on dry roads can build up a static charge of a few thousand volts.
There are several solutions, conductive straps or chains that touch the road, or I have heard of people using pencil ( Graphite) and draw lines on the inside of the tyre from the rim to the tread in several places....###
Now this will open a few more discussions..:doh
Kath, certainly from reading the post, I would go for the battery terminals, clean up both the battery pillars and the battery connectors.
Be aware you will loose your radio so you will need the code, the NATS ( Nissan Anti Theft System ) tends to reset ok after battery re-connection, and the ECU ( Electronic Control Unit ) will re-learn the settings after a good run.
A cheap fix, especially if the terminals weren't cleaned up on battery replacement last year.
Good luck,
Rustic