↓ Advertise on Defender2 ↓

Home > Technical > Could a faulty alternator be discharging battery overnight?
Post Reply  Down to end
Page 1 of 1
Print this entire topic · 
chopcat



Member Since: 11 Sep 2012
Location: Pembrokeshire
Posts: 408

Wales 2000 Defender 90 Td5 CSW Java Black
Could a faulty alternator be discharging battery overnight?
Tell you why..

I have started getting overcharging alarms on the luna twin battery meter when the car is running. I thought nothing about it but it has now started to drain the battery overnight. Luckily i have the second battery isolated so i have not got stuck so far.

Could it be that the two are linked and that something in the alternator has gone and results in both symptoms?

CC
Post #391090 21st Jan 2015 5:27pm
View user's profile Send private message View poster's gallery Reply with quote
VeeTee



Member Since: 06 Mar 2011
Location: Somewhere
Posts: 1512

Netherlands 
Yes, that is possible. There are diodes in de alternator (regulator), if one of them fails it can drain the battery. Cheers, Vincent
1959 Polynorm 1/4 Ton Trailer, Olive Drab Green (sold)
1970 M416 Military Trailer (Camping Trailer Conversion), Epsom Green (sold)
1975 Series III 88 V6, Light Green (sadly sold)
1996 Defender 110 CSW 300 Tdi, Epsom Green (sold)
2000 Freelander 1 TD4 3-drs, Silver (sold)
2006 Freelander 1 TD4 5-drs Facelift Automatic, Tonga Green (sold)

MySite
Post #391093 21st Jan 2015 5:36pm
View user's profile Send private message View poster's gallery Reply with quote
chopcat



Member Since: 11 Sep 2012
Location: Pembrokeshire
Posts: 408

Wales 2000 Defender 90 Td5 CSW Java Black
i shall investigate further with a bit of testing.

I have a 2000 TD5 120k miles is it likely that the regulator is replaceable or is it better to bite the bullet and get anew alternator completely?

CC
Post #391094 21st Jan 2015 5:38pm
View user's profile Send private message View poster's gallery Reply with quote
VeeTee



Member Since: 06 Mar 2011
Location: Somewhere
Posts: 1512

Netherlands 
You can have te alternator (including regulator) tested by a specialized company. They also can revise the alternator or swap it with a refurbished one. Or buy a new one.

I just had mine refurbished last week, it had been in use for 5 years, approx. 100 k km. Cheers, Vincent
1959 Polynorm 1/4 Ton Trailer, Olive Drab Green (sold)
1970 M416 Military Trailer (Camping Trailer Conversion), Epsom Green (sold)
1975 Series III 88 V6, Light Green (sadly sold)
1996 Defender 110 CSW 300 Tdi, Epsom Green (sold)
2000 Freelander 1 TD4 3-drs, Silver (sold)
2006 Freelander 1 TD4 5-drs Facelift Automatic, Tonga Green (sold)

MySite
Post #391110 21st Jan 2015 6:11pm
View user's profile Send private message View poster's gallery Reply with quote
munch90



Member Since: 26 Oct 2013
Location: guildford
Posts: 3558

England 
Quite common for alternator fault to cause battery drain
Post #391162 21st Jan 2015 7:50pm
View user's profile Send private message View poster's gallery Reply with quote
chopcat



Member Since: 11 Sep 2012
Location: Pembrokeshire
Posts: 408

Wales 2000 Defender 90 Td5 CSW Java Black
am having second thoughts.
tonight i got back to it and both batteries were good.

turn on the ignition and it seems to be draining huge current. so much so that the firs battery would not turn the engine snd only by linking the second did it turn over just.

I will measure it over the weekend. but there certainly seems something linked to the ignition that is killing it. and maybe not a gradual discharge.

we shall see. and thanks for all the suggestions so far.

CC
Post #391237 21st Jan 2015 9:42pm
View user's profile Send private message View poster's gallery Reply with quote
Ken B



Member Since: 17 Dec 2013
Location: Essex
Posts: 106

Hiya chopcat,

I had a similar issue recently, it turned out in my case the alternator was caked in mud after some deep wading! It seems that it shorted the circuit in some way and caused it to drain.. A heavy session with the pressure washer and all was resolved...

Check the voltage on the battery terminals when the vehicle is running you need around 14.7v, when you are all switched off you should have over 12v, test and take a reading then test in 12hrs to see what your result is the drop should be negligible if there is no drain.

In my case It did in fact fully discharge my main battery but fortunately I have some conditioning chargers and was able to recover safely in the workshop.

K.. Defender 90 TD5 County -
You need only two tools in life: WD-40 and duct tape.
If it doesnt move and it should: WD-40.
If it moves and shouldnt: duct tape it.
Post #391248 21st Jan 2015 10:05pm
View user's profile Send private message View poster's gallery Reply with quote
chopcat



Member Since: 11 Sep 2012
Location: Pembrokeshire
Posts: 408

Wales 2000 Defender 90 Td5 CSW Java Black
It appears that the alternator is working ok and that the overchard warnings from the luna gauge are quite usual when its cold.

I have a drain of about .5a so need to see if that is the cause but i have a feeling that this is something to do with the second battery and the relay which i have now isolated totally from the system to see if that cures it.

As i have added various bits on over time I think that I need to re wire these when it gets warmer and do a thorough check as I do it.

cheers
Post #391688 23rd Jan 2015 8:40am
View user's profile Send private message View poster's gallery Reply with quote
Naks



Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2579

South Africa 2010 Defender 90 Puma 2.4 SW Alpine White
Do you have a tracking device in your landy? If so, make sure the battery in there is not kaput, we had this issue on SWAMBO's Audi. --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport V8 Supercharged



Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ
Post #391696 23rd Jan 2015 9:00am
View user's profile Send private message View poster's gallery Reply with quote
chopcat



Member Since: 11 Sep 2012
Location: Pembrokeshire
Posts: 408

Wales 2000 Defender 90 Td5 CSW Java Black
a very good point. yes and its quite old so i shall get that looked at

cheers for the thought

CC
Post #391698 23rd Jan 2015 9:02am
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 1 of 1
All times are GMT

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2006-2024 Futuranet Ltd & Martin Lewis
DEFENDER2.NET RSS Feed - All Forums