TD5 alternator overcharging - 14.8 volts?

**twr7cx** · 25th June 2013, 05:58 PM

I'm having some electrical issues with the vehicle.
I run a dual battery system with a standard Land Rover 850cca battery and in a dual battery tray an Optima D34/78 ( http://optimabatteries.com.au/wp-con...-YellowTop.pdf ) battery in a tray with a Matson Low Voltage VSR Parallel Switch ( Low Voltage VSR Parallel Switch | Matson ).

Over the last few weeks I've been having some issues with this. Frequently when starting the car I have the drivebelt squealing as the alternator tries to get the battery voltage up (I have changed the drivebelt to a brand new one and tried CRC Belt Grip).

Despite the vehicle being driven almost daily, four times the battery has been too low to start the vehicle, requiring a jump start (and I have to leave it connected for a minute or two to bring the Land Rover up to a level before it can start).

At first I figured it was likely to be a failed battery since the temperatures here have just dropped hitting as low as 0*C!
I removed the secondary battery from the system by disconnecting it to ensure that this was not the cause - problem continued.
I swapped the Land Rover battery with a Caterpiller 1000 CCA unit and the problem continued.

Started monitoring the battery voltage, and I have noted that it gets as high as 14.8 volts (this is with the headlights on, stereo playing, cruise control on and climate control running!

I believe this is higher than it should be. Rave doesn't seem to discuss any charging specifications in the section on CHARGING AND STARTING, so I'm not sure.
Does this sound like a failed regulator on the alternator?

**justinc** · 25th June 2013, 06:04 PM

Scott, 14.8 is the highest, even when revved? if so that is fine. 17 to 20v is overcharging with these

i would suggest checking the tensiioner to see if it is 'lazy', ie not freely pushing against the belt.

jc

Tombie · 25th June 2013, 06:25 PM

14.8v is pretty tame if that's the peak.

Hence the use of Calcium batteries..

**twr7cx** · 25th June 2013, 07:17 PM

Originally Posted by justinc

Scott, 14.8 is the highest, even when revved? if so that is fine. 17 to 20v is overcharging with these

Originally Posted by Tombie

14.8v is pretty tame if that's the peak.

Hence the use of Calcium batteries..

14.8 is a constant voltage though. So it'll be on that the whole 15km drive to and from work.

It doesn't really fluctuate much with the rpm.

Originally Posted by justinc

i would suggest checking the tensiioner to see if it is 'lazy', ie not freely pushing against the belt.

Will do, but the spring seemed pretty strong on it when I changed the belt over.
Also the squeal only occurs on start up, not while I'm driving which makes me think it's not the belt tensioner thats the issue.

Perhaps I've got an issue then with something draining the battery then?

**PhilipA** · 25th June 2013, 08:30 PM

14.8 is a constant voltage though. So it'll be on that the whole 15km drive
to and from work.

15Km X2 each day is not enough to charge 2 batteries. So the alternator will stay up at 14.8 if the volts are low in the battery.
I had a similar problem and just put it on a 20Amp charger every now and then.
Regards Philip A

**twr7cx** · 26th June 2013, 11:44 AM

Originally Posted by PhilipA

15Km X2 each day is not enough to charge 2 batteries. So the alternator will stay up at 14.8 if the volts are low in the battery.
I had a similar problem and just put it on a 20Amp charger every now and then.
Regards Philip A

It's been doing it fine for the last two years though... Actually last year I was working much closer to home so the drive was only around 5km each way!

I drove it again last night, the entire drive it stayed at around 13.9 - 14.0 volts with a peak of 14.1 a few times. There was no belt squeal on start up.

It seems to be only that if I have the belt squealing on start up then the alternator charges high (i.e. 14.8) - which makes sense as if the belt is squealing then it's likely the battery was low.

I'll test the current draw this weekend. Perhaps the issue lies there.

**PhilipA** · 26th June 2013, 02:42 PM

Maybe because one or both of your batteries are now getting old , they are not keepnig their charge.
When I bought my D2 , it had a 3 year old 800CCA battery which was on the way out, and it would lose charge overnight. When I fitted the second battery I would see the volts go down to below 12.4 next morning and the duals would disconnect.
Regards Philip A

**jf1056** · 26th June 2013, 02:58 PM

When I start mine lately and now most mornings I get the squealing belt. I have 2 batteries but the sqealing stops as soon as I turn the AC compressor off, IE the ECON button, turn it on gets a squeal, it does stop after a short time. I did a deep creek crossing a few weeks back and it was only after that it started. The tensioner seesmed a little suss but on closer inspection it is just the belt has worn, so this needs to be replaced.
This may be all that is your problem, the alternator does load up but not as much as the AC Compressor. I will be replacing my belt and expect no more issues..........................but is is a Land Rover!

**twr7cx** · 26th June 2013, 03:32 PM

Originally Posted by PhilipA

Maybe because one or both of your batteries are now getting old , they are not keepnig their charge.

If you reread the first post I have now disconnected the secondary battery (as it's not required for normal driving) and replaced the main battery with a brand new 1000CCA Caterpillar unit.
It is possible however that the new battery is faulty.

Originally Posted by jf1056

When I start mine lately and now most mornings I get the squealing belt. I have 2 batteries but the sqealing stops as soon as I turn the AC compressor off, IE the ECON button, turn it on gets a squeal, it does stop after a short time. I did a deep creek crossing a few weeks back and it was only after that it started. The tensioner seesmed a little suss but on closer inspection it is just the belt has worn, so this needs to be replaced.
This may be all that is your problem, the alternator does load up but not as much as the AC Compressor. I will be replacing my belt and expect no more issues..........................but is is a Land Rover!

It's about 3*C here most mornings so my airconditioner has been turned off for a while!

As per my first post I have also replaced the drivebelt already with a brand new unit.

**PhilipA** · 26th June 2013, 03:55 PM

If you reread the first post I have now disconnected the secondary battery
(as it's not required for normal driving) and replaced the main battery with a
brand new 1000CCA Caterpillar unit.

To check, put a volt meter across it before you start in the morning. If it is much less than 12.6-12.5 then you may have a battery problem. check it also after a run, and after settling the surface charge by running the headlights for 5 minutes. Voltage should be => 12.7.

My D2 drain is about 0.2 amps , so maybe also check the current across either the + or - terminal while switched off. More than 0.2 amps is probably indicative of some drain.

Regards Philip A

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