Thread: Battery voltage down to 12.7

Vehicle type may help get some responses and advice ??

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?

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?

Originally Posted by DiscoMick

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.

Got 226000 on the clock, is it time for a new alternator?

Originally Posted by TheEntertainer

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.

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.

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