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TheEntertainer
26th April 2019, 07:51 PM
Hi all,

I noticed over the last few days that for prolonged periods of time the voltage input to the main battery when driving drops down to 12.7 and would stay there for 20-30 minutes.

Is it not supposed to sit at 13.7? All the time?

Td5 defender

Thanks

J
scarry
26th April 2019, 07:53 PM
Vehicle type may help get some responses and advice [biggrin]??
p38arover
27th April 2019, 08:25 AM
12.7 is fully charged for a battery that isn't on charge. It sounds like your alternator is not charging the battery. faulty alt or a connection problem?
DiscoMick
27th April 2019, 10:23 AM
Yep, 6 x 2.1 is fully charged.
Also depends on whether the alternator has variable or fixed output. My Defender just sits on 13 all the time, but newer vehicles such as D4s have variable outputs which drop down once the battery is fully charged.
What vehicle do you have?
DiscoMick
27th April 2019, 10:24 AM
Yep, 6 x 2.1 is fully charged.
Also depends on whether the alternator has variable or fixed output. My Defender just sits on 13 all the time, but newer vehicles such as D4s have variable outputs which drop down once the battery is fully charged.
What vehicle do you have?Oh, sorry, a Td5 - missed that.
TheEntertainer
27th April 2019, 10:27 AM
Got 226000 on the clock, is it time for a new alternator?
DiscoMick
27th April 2019, 11:19 AM
Got 226000 on the clock, is it time for a new alternator?Get an auto electrician to test it. Might just need a service and cleanup.
scarry
27th April 2019, 01:22 PM
TD5 didn't have variable voltage alternator,so something could/is going on.

Only 3.0l D4 had BMS and variable voltage alternator,2.7l D4 didn't.
ian4002000
27th April 2019, 03:49 PM
12.7 volts isnt a huge problem. does the voltage increase/ decrease when headlights and all accessories are turned on and off ?
Does the voltage start higher first up in the morning and reduce later ?
What is the voltage of the battery before you start the vehicle and what is the voltage when cranking ?

At 225000 kms i would be considering getting the alternator replaced or rebuilt and it is usually cheaper in parts and batteries to do this earlier than later. and check your idler pulley at the same time.

Ian
Bittern
DiscoMick
27th April 2019, 05:44 PM
Yeah, alternators are not that expensive. Get a new one for peace of mind.
TheEntertainer
12th June 2019, 06:26 AM
Bit early yo tell but after replacing the SM relay the voltage is back to 13.9. Could that have been the issue...
TheEntertainer
7th August 2019, 03:52 PM
Solved, one of the wires was not in good shape. Replaced it and all has been good. Hey!