Battery Voltage
1 - 7 of 7 Posts
Mine shows somewhere between 10.8>11.2 before start up & stays that way till i've ethier driven about 300yds,or cycle round the info button.It then goes to an acceptable level 13.8>14.2 depending on whats running on the electical side.
It has on previous models dropped to below 10,at which point the alternator gave out
![]()
.
As long as you get a good reading when the engines running i wouldn't think the alternator has any problems (unless its grating the bearings)if it is low,but charges,it maybe the battery on its last legs ??
2.3 93'CSE btw.
G.
It has on previous models dropped to below 10,at which point the alternator gave out
As long as you get a good reading when the engines running i wouldn't think the alternator has any problems (unless its grating the bearings)if it is low,but charges,it maybe the battery on its last legs ??
2.3 93'CSE btw.
G.
Joined
·
776 Posts
Hi,
Just to confirm what the last posting says really, if t helps to assure you that there is a correct tolerance in the readings.
Mine comes up roughly between 10.7 & 11.2 when turning key. Once engine is started, I too have to cycle through trip computer and it refreshes itself.
If I have all the toys on, AirCon, Fan, lights, CD etc, it may drop to as low as 13.6, but generally with just one thing on it settles to around 13.9...
(It has never been lower than 13.6, or higher than 14.2 by the way).
Cheers,
Andy.
Just to confirm what the last posting says really, if t helps to assure you that there is a correct tolerance in the readings.
Mine comes up roughly between 10.7 & 11.2 when turning key. Once engine is started, I too have to cycle through trip computer and it refreshes itself.
If I have all the toys on, AirCon, Fan, lights, CD etc, it may drop to as low as 13.6, but generally with just one thing on it settles to around 13.9...
(It has never been lower than 13.6, or higher than 14.2 by the way).
Cheers,
Andy.
Joined
·
776 Posts
Sorry, car in question is a '94 9000 CSE 2.3 FPT
Andy.
Andy.
*Before* you crank the engine, it should be 12.0V +/- 0.2V if you have everything else off.
I have just driven my CS 2.0 LPT for an hour and a half with a dead alternator (battery alone) and it was showing between 11.7 and 12.2, depending on brake-lights, indicators etc. Scary trip as it was getting dark!
Joined
·
14,305 Posts
The dash voltmeter readings are not always very accurate- they are often not calibrated properly. It's best to check the terminal voltage with a multimeter. You can correct any errors with Tech 2.
The thing to watch for is if the reading changes from what it has been previously.
The thing to watch for is if the reading changes from what it has been previously.
Further to Marks comment above...
The Handbook states voltage shouldn't fall below 11v under starting load, but we all know it does!
Of course, voltage will be lower in winter and cold mornings (when battery is cold and hence power level drops), and higher when outside air temp is warm. Also, if engine is already warm, the battery will need to provide less power for easier starting, hence pre-fire battery voltage will drop less.
The voltage display should show initial battery level when ignition turned on, then following engine fire up, it holds the voltage that the battery dropped to under load, for approx 3 seconds - before returning to alternator output voltage.
The Handbook states voltage shouldn't fall below 11v under starting load, but we all know it does!
Of course, voltage will be lower in winter and cold mornings (when battery is cold and hence power level drops), and higher when outside air temp is warm. Also, if engine is already warm, the battery will need to provide less power for easier starting, hence pre-fire battery voltage will drop less.
The voltage display should show initial battery level when ignition turned on, then following engine fire up, it holds the voltage that the battery dropped to under load, for approx 3 seconds - before returning to alternator output voltage.
1 - 7 of 7 Posts
Join the discussion
