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TallXIII

Member

• Oct 25, 2019

• #1

So I've been having issues with battery drain for just over a year or so now.
It would normally take between 3 and 4 days of being stood to drain but I fitted an isolator and all was good, well as good as it could be
But last week it started dropping over an 8 hour period, only by a volt or so but enough to not start.
Needless to say it's become a concern as I dare not go to far in case I can start it up, can anyone offer up any ideas?
I don't know if it's anything to do with the long term drain getting worse but I'm just wondering if it has or its something else entirely.

Cheers

 

sierrafery

Well-Known Member

• Oct 25, 2019

• #2

What about the voltage with engine running ? ... and what kind of disco ?

 

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TallXIII

Member

• Oct 25, 2019

• #3

Sorry it's an 02 plate td5 D2, it's charging at around 14.29-14.35

 

sierrafery

Well-Known Member

• Oct 25, 2019

• #4

You'll have to measure drain on the engine bay fuses, use the procedure from the video then report on which fuse you get the big value

 

robhew86

Well-Known Member

• Oct 25, 2019

• #5

You sure the battery itself is in top working order and not been on it's way out??

In my experience, when a car battery has died, it's never the same again...

I thought my RR had a drain but it didn't.... Was just the battery slowly coming to it's death

 

T

TallXIII

Member

• Oct 25, 2019

• #6

The battery is only a year old and the initial drain was before it was replaced

 

Stanleysteamer

Well-Known Member

Full Member

• Oct 27, 2019

• #7

I take it you have connected an ammeter between the bat and its connector on one side to check the amount of current drain once it is just sitting there, "turned off"?

 

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TallXIII

Member

• Oct 28, 2019

• #8

Every 2 hours in an 8 hour period it dropped just over half a volt

 

Stanleysteamer

Well-Known Member

Full Member

• Oct 28, 2019

• #9

R U sure all interior lights, in the glove box etc are going off? Nothing else plugged into a system not via the ignition switch first position? No wires chafed through with a positive feed earthing to the chassis or bodywork? Did you follow SF's thing?

 

Europa486

Well-Known Member

• Oct 28, 2019

• #10

Even a year old battery can be duff, one cell goes down and takes power from the other five,
Disconnect battery and fully charge her, leave her for 24 hours then check it’s voltage,
If it’s below 13volts it’s the likely suspect, very often alternators can consume power feeding back through the diodes,
So disconnect the heavy brown lead and see if you are still loosing power overnight,

 

kermit_rr

Very

Full Member

• Oct 28, 2019

• #11

A battery that's been left off charge overnight should settle down to around 12.8v at best if there is no draw on it