Battery Test

[Rev Jules]

Got one of these gadgets that tests the battery voltage, showing 13.2 would that be the output from the alternator, or is it the actual state of the battery.

Rev

[steve-45]

Depends if the engine is running.

With engine off its the static battery condition.

[Rev Jules]

Originally Posted by steve-45

Depends if the engine is running.

With engine off its the static battery condition.

Hi Steve.
That's with the engine running. on my others it shows 14 plus.

Rev

[Arctic]

Hi Rev.
A good battery state should measure 12.6 volts when standing no engine running, with engine running volts should be 14.7 bit of a scale below for you Arctic.

STATE OF BATTERY CHARGE SET OUT BELOW.
Voltage State of Charge
12.6+ 100%
12.5 90%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%
BATTERY SHOULD NOT HAVE BEEN CHARGE OR USED FOR ABOUT 1 HOUR BEFORE THIS TEST IS UNDERTAKEN.
I am not shouting in the above text just highlighting it

[Mickyboy]

Originally Posted by Arctic

Hi Rev.
A good battery state should measure 12.6 volts when standing no engine running, with engine running volts should be 14.7 bit of a scale below for you Arctic.

STATE OF BATTERY CHARGE SET OUT BELOW.
Voltage State of Charge
12.6+ 100%
12.5 90%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%
BATTERY SHOULD NOT HAVE BEEN CHARGE OR USED FOR ABOUT 1 HOUR BEFORE THIS TEST IS UNDERTAKEN.
I am not shouting in the above text just highlighting it

I completely agree with your chart relating to the static battery percentage before the engine is running, however from a lot of testing I have done recently I have found that the ECM controls the charge rate and is putting out a higher charge rate when the engine is cold approximately 14.6 /14.7 however once the vehicle is up to temperature the ECM reduces the charge rate back down to approximately 14.3.volts
Mick

[Rev Jules]

Originally Posted by Arctic

Hi Rev.
A good battery state should measure 12.6 volts when standing no engine running, with engine running volts should be 14.7 bit of a scale below for you Arctic.

STATE OF BATTERY CHARGE SET OUT BELOW.
Voltage State of Charge
12.6+ 100%
12.5 90%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%
BATTERY SHOULD NOT HAVE BEEN CHARGE OR USED FOR ABOUT 1 HOUR BEFORE THIS TEST IS UNDERTAKEN.
I am not shouting in the above text just highlighting it

Cheers Artic.
Its just the battery seems to be losing its charge over a couple of days, is a new battery imminent.

Rev

[Mickyboy]

If it’s putting out 13.3v on Idle then that alternator is faulty mate, that’s way to low, by the time you start running accessories like lights, heater, radio et cetera it will be below 13 volts.
Mick

[Rev Jules]

Originally Posted by Mickyboy

If it’s putting out 13.3v on Idle then that alternator is faulty mate, that’s way to low, by the time you start running accessories like lights, heater, radio et cetera it will be below 13 volts.
Mick

Is that the ultimate answer, or could the battery not be capable of taking a charge.

Rev

[Brunty]

Last Friday when my car would not let me in, everything was frozen. On Saturday morning I tried battery voltage with a Draper battery tester, it lit up on red showing 5 volts. Battery knackered! Now replaced.

[Mickyboy]

Originally Posted by Rev Jules

Is that the ultimate answer, or could the battery not be capable of taking a charge.

Rev

I’d have fully chargethe battery off the car left overnight and tested 24hrs later expecting the battery to have 12.6volts or there about, then placed on car started and using a multimeter monitor the charging rate, from cold expecting to see 14.6/7 volts when cold, once warm I’d expect to see the rate drop to 14.3 volts or around that figure.
Then I’d turn on all accessories and see what charge rate it’s producing, A fluctuating charge rate is sometimes caused often by the regulator.

However if you have a drop tester available like I do I would simply drop test it initially And that would allow me to get a insight into the battery condition itself.

You will find that in some cases our alternators fail early due to the alternator not be protected with rags or the such like when changing the oil filter, not suggesting that this has happened in your case.

Does the battery light illuminate while the engine is running? And do you have message center or a non message centre IPK
Hope that helps
Mick