Noticed a bit of odd behavior with the in-dash volt gauge.

Key to ON position (not start) = 11 volts
Key to cranking position = drops to 10 volts
Engine started, release key = up to 11 volts
After about 5 seconds, voltage rises to 14 volts
When on the road, 14.5+ volts.

I did a volt meter test of the battery (yesterday) and it showed 12.3 volts - according to the volt-meter manual, that's about a 50% degradation of the battery's life. I took the battery to the parts store (this AM) where i buy batteries from, and they did a charge (needed 15 minutes worth) and a load test and they state the battery is fine.

Belt is fine and proper tension and i've sprayed belt dressing on yesterday. I questioned the behavior when i stopped at a stop light a couple days ago (at night, lights on, heater on, 45*F weather) and the voltage dropped to 12 volts (should be 14.5 or so).

I spent about 15 minutes this morning checking the tightness of the various grounds straps in the trunk and under-hood (the visible ones).

My concern is the Key to ON position = 11 volts ... is that what other folks witness? I would think the normal voltage would be 12-something volts at key ON (not started).

OK, checked mine as a comparison.

Battery, at the battery = 12.6v

Ign ON =12v and a bit, battery still 12.6v

Start/crank pos is a tad hard, coz mine fires at first rotation, and the gauge/meter are not reactive enough to register.

Running, immediately after start = 14.2v, and settles to 13.6 +/- after 30 minutes or so. This is AT the battery, and the dash gauge is close to that same.

With a/c on, lights on, brakes on (lights that is) in "D" 13.6v at the battery, and 13 and a bit on the dash.

I reckon you have a battery that is one the way out, as we say. If in doubt, purchase a home charger, 4 amps is fine, and charge it overnight yourself, and see what if anything changes. My Jags get the batteries charged every month, and I have NOT purchased a battery for 9 years now.

I know you are up there and I am down here, but fair dinkum a 15 minute charge is not on. A battery requires a 24 hour "soaking charge" prior to any diagnostics. We have a C-Tec charger at work and anyone with a battery that is suspect, MUST leave it for an overnight "soak" prior to doing a load test etc. Batteries that are "belted" with these so called fast chargers mostly die in the near future, they just do not like it.

Hi Grant ... thanks for spending the time to provide a comparison.

I will get my meter out and do true voltage tests at the battery, rather than using the car's gauge.

For whatever it's worth, i did do a trickle charge (my charger can be set for 12v 6a or 12v 2a) overnight at the 2amp setting, before bringing the battery in for a test ... maybe that's why the auto parts store didnt have to do much of a charge?

I purchased the battery a year ago, almost to the month ... it's a 600 CCA @0*F / 750 CCA @ 32*F.

I'm sure you get temps Down Under similar to what we get here in Houston Texas ... it's not uncommon for us to endure 100*+F temps (plus 90% humidity) for 5-6 months, then as in the last few days , temps drop dramatically, which is taxing on a battery. Our "winter" lasts about 2 months, as a rule.

Again, i much appreciate you spent to the time to provide a comparison. I'll take more readings at the battery with the meter ...