Battery testing

[RBS-C5]

Paul - In your column lock videos I understood you to say that the minimum battery parameters for the C5 are 12.5v and 500 CCA.

Using the Solar BA7 battery tester I got 9.92v during the cranking test. The BA7 still gave me a green LED on the cranking voltage test. Is this the reading that you say should not fall below 12.5v?

All the other tests on the battery and charging system got the green LED and CCA measured as 800. Am I correct in assuming that you would say "replace it" due to the low cranking voltage?

The reason I got the tester was because 1) it's a neat tool and 2) while working on the car recently I had the doors open for around 6 hours and the ignition on for about an hour. After the 6 hours I got a warning on the DIC that said "Low battery voltage 9.6 volts" - and the car would not crank. Overnight on a trickle charger allowed it to crank - but that's when I ordered the BA7.

[c4c5specialist]

Hi there,

Yes, replace it.

Allthebest, c4c5

[RBS-C5]

Which test on the BA7 corresponds to your 12.5v minimum in the videos? I'm guessing the cranking voltage...

[c4c5specialist]

HI there,

The standing voltage when you first connect to the battery.

Then, if the voltage passes, then you test for CCA.

Just remember, if your battery terminals are NOT clean and NOT torqued correctly, you will get false readings.

Allthebest, c4c5

[RBS-C5]

In the video you mentioned that the trick to getting a torque wrench on the battery terminals is to tip the battery back.

I tried that and still did not have enough room for a torque wrench. Perhaps if I also moved the base of the battery forward while tipping the top backwards that might provide enough room for a torque wrench.

What is your technique?

Or, do you just have a small torque wrench?

[c4c5specialist]

HI there,
1/4 in drive torque wrench, and a 8mm short socket is all I use.

Allthebest, c4c5

[RBS-C5]

Originally Posted by c4c5specialist

HI there,
1/4 in drive torque wrench, and a 8mm short socket is all I use.

Allthebest, c4c5

That explains it, I have a 3/8" torque wrench.

Guess I'll be getting a 1/4" torque wrench next.

[RBS-C5]

Originally Posted by c4c5specialist

HI there,

The standing voltage when you first connect to the battery.

Then, if the voltage passes, then you test for CCA.

Just remember, if your battery terminals are NOT clean and NOT torqued correctly, you will get false readings.

Allthebest, c4c5

What is the minimum cranking voltage that you recommend for the C5? I.e. the voltage level that if the battery falls below that voltage while cranking you would replace the battery.

[c4c5specialist]

Hi there,

NOTHING lower than 10 VOLTS!!!!

Allthebest, c4c5

[RBS-C5]

Originally Posted by c4c5specialist

Hi there,

NOTHING lower than 10 VOLTS!!!!

Allthebest, c4c5

This is an update on what I've discovered.

With my old battery I consistently got cranking voltages in the 9.8 - 9.9 volt range (with no column lock issues), so I got a new ACDelco 78-6YR battery. To my surprise that battery also got cranking voltages in the 9.9 volt range (with freshly cleaned battery connections and 11 ft-lb torque). All the while the green LED on the BA7 was lit during the cranking test.

I contacted cloreautomotive.com (makers of the Solar BA7 battery tester) and asked what range of voltage they use to transition from green to yellow to red LED. Their answer is below, but the interesting thing is that they consider a cranking voltage of 7.2v or higher to be OK.

I tried the BA7 on a friend's C5 with an older battery and his cranking voltage was 8.4v, still with no column lock issues and the green LED.

This leads me to wonder if the BCM is smart enough to not to make the column lock check during or shortly after cranking. That would make sense considering that 10v or higher is required for the BCM's column lock test to function properly. I would think that the BCM would make any voltage sensitive tests as soon as the ignition switch was ON, but prior to cranking.

I suppose that if the BCM makes the column lock test shortly after cranking, and due to a degraded battery the voltage has not risen to over 10v by the time the test happens - that could cause the column lock problem.

Are you still convinced that a cranking voltage of less than 10v indicates a problem?

Solar BA7 LED transition voltages:

Charging system test
Normal (green): 13.4 - 14.6 Volt
High (red): > 14.6 Volt
Low (yellow): < 13.4 Volt

Starting system Test
OK (green): > 7.2 Volt
Weak (yellow): < 7.2 Volt
Problem (red): < 4.8 Volt