TD5 Charging Question

[CraigE]

Charging Question.
OK just another issue with the Defender, all of a sudden alternator does not seem to be charging properly. It seems to for the first part of the drive and then drops below 13v. I have it on charge at work atm. Did the same yesterday and dropped main battery to around 12.5v causing it to run rough. I am fairly certain the alternator is OK, but will need to work out how to test. Only put a new one in a few months back. How likely is it there is an issue with the charge wire to the battery?
This thing is really trying my patience lately.
Any easy way to test the alternator at the alternator?
I dont have my multi meter on me atm to tong the battery, but Nanocom shows it is not charging as does volt meter, though it does seem to intermittently kick in.
Time to look for a new dual cab I think.
Cheers
Craig

[Slunnie]

In my Td5 Disco, the GPS always displays the voltage and its pretty normal for it to start at a higher voltage than lower the voltage. It usually starts somewhere in the 13's, I have seen it in the very low 14's I think. After its been running for a while it will be in the mid-high 12's.

[CraigE]

In my Td5 Disco, the GPS always displays the voltage and its pretty normal for it to start at a higher voltage than lower the voltage. It usually starts somewhere in the 13's, I have seen it in the very low 14's I think. After its been running for a while it will be in the mid-high 12's.

Yeah just seems to be a bit lower than normal since my rear wheel departure and I had to refit a set of old ABS sensors.

[AK83]

The voltage will depend on where you take the reading from.

I have a few volt meters in my D1.
Kind'a not my fault, just the accessories I've installed.

Main volt meter is the 1Gauge set, which have the aux battery connects at the battery, and the main battery connect at the ign feed.
I also have a few USB ports, and they all have volt meters on their faces .. just the easiest types to find cheaply.

I've checked them all and they all fall within a 0.1v accuracy range.

So 1Gauge usually shows about 14.1v after about 30sec on the main, and usually about 14.3v on the aux.
At the same time tho, the USB ports show 13.9-14.0 volts on the main(direct connect), and the USB connected direct to the aux displays voltages closer to what the similar connection that the 1Gauge shows(about 14.3v).

Of course as already said, once they've charged a fair bit, they do drop.
But lights, indicators, fan(vent), brake lights .. they all affect the 1Gauge main batt reading, more so that the USB port directly connected to the battery does.
That is, the 1Gauge, the way it's connected via the ign feed seems to show a more accurate voltage of the drop in volts, as various electrical components would impact the battery.

eg. where the 1Gauge might show 13.8v with the park lights on, the USB port meter will show 13.9v or maybe even 14.0v concurrently.
similarly with the Aux, where if I have my fridge connected at the dash port(which is wired along with the USB port), it shows a larger voltage drop with the fridge running, than I see on the 1Gauge.

So it begs the question, what have you got running when you see your voltages, and how is the volt meter connected?

Although, in saying that 12.5v is way too low, unless you have a lot of electrical equipment on at the same time .. eg. A/C(the condenser fan uses a lot of power(I think more than 10A), lights(LEDs save a fair amount of power), radio/amp .. etc.
Going by your description, sounds like a regulator issue, if it seems to be kicking in intermittently.

[PhilipA]

Geez that all sounds complicated.
The alternator should start off at about 14.2-14.4 cold.
Then should drop to 13.8- 13.9 hot with no loads like aircon , lights etc.
I have mine measured at the battery terminal and have checked against a multi meter.
You probably have a crook diode, as brushes are go/no go.

Regards Philip A

[trout1105]

Geez that all sounds complicated.
The alternator should start off at about 14.2-14.4 cold.
Then should drop to 13.8- 13.9 hot with no loads like aircon , lights etc.
I have mine measured at the battery terminal and have checked against a multi meter.
You probably have a crook diode, as brushes are go/no go.

Regards Philip A

I had a similar problem with my D2a's alternator with the charge working on startup then failing after a few k's and all it took was to replace the brushes in the alternator.
I have done more that 15k since the repair and the alternator is still going strong[thumbsupbig]