Thread: 2011 D4 Battery Charging Voltage

Seems fine to me, pretty sure ours is about the same.

I'm no expert, but as I understand it the cigarette socket meter (I also have one) is not reading the voltage produced by the alternator. Its actually reading the level of electrical current flowing in your vehicle's electrical system. Both your battery and your alternator are feeding current in, but they could be producing at different voltages. So your alternator, battery and the electrical system could each give a different reading.
For example, I think your D4 would have a smart alternator which is charging the battery and varies it's output depending on the state of the battery. Your battery would be fully charged at about 12.7 volts, but could go above that depending on how much charge it is receiving from the alternator and what demand is on the battery. Your alternator could be varying it's output to keep the system operating at the ideal voltage.
I'm sure some expert will be along soon to give a better explanation.

Cigarette lighters often have a bit of voltage drop, therefore will show a lower voltage. If you have a multi meter just measure it at the battery

Mine sometimes goes to 14.5v according to both the cigarette lighter socket voltmeter & my GAP Tool.

Hi All of the above might true but on my car (2012) it goes up to 14.8/9 (measured on the Jayco meter plugged into lighter socket) after it starts and ten comes down slowly after that. It stays around low 14s once fully charged. Also when I coast off the throttle it jumps right up to 14.8/9 again even when fully charged. I understand that this is how it is supposed to work.

When the car has sat for a long period and I start it, I will see for a few seconds 15v. This can be a concern as I have Traxide DBS which is programmed to cut out at 15, but it hasn't been an issue.

I personally think your charge rates (at least if the voltmeter is to be believed) are a bit low for my liking.

Cheers J

Slightly different charge logic from 2012 onwards I believe....

Again, charge depends on current battery state and temp.

Would say that voltage through ancillary plugs would be 'limited' /restricted and effected by relays and number of different terminals and line changes/regulators etc.
best to use a multi meter straight onto battery.

• try before starting (with ignition off etc)
• start and measure again.
• them measure after a few mins to see a flat line charging state

shows if alternator working at the very least.

Also check once stopped for a while - and see if any current draw if you have a decent clamp meter (with DC capability) it can help tell you what the car is drawing in an idle state

Originally Posted by John & Deb

Hi All,
I've read here that that charging voltage rises up to 14.4V under certain driving conditions, but in my 2011 D4 it never changes from 13.8 or 13.9V (as measured by cigarette socket voltmeter), no matter whether I'm accelerating, cruising, braking or idling.
Is this OK?
Cheers, John

Is it a 2.7l or 3.0l?

If 2.7,that is identical to mine,i monitor the voltage with a cigarette lighter read out as well.Mine is always somewhere between 13.7 and 13.9 all the time.

As far as i know the 2.7 didn't have a variable voltage alternater,where the 3.0l did.

And for the record,the battery voltage is identical to the cigarette lighter read out.