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Battery drain

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Old Nov 1, 2011 | 04:14 PM
  #1  
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Default Battery drain

Inaugural post although been member for some time - usually can find answers through search.
This one has me head-scratching a bit .......

99 LX470 - battery has been draining over last few days - actually first noticed yesterday after changing brake pads.
Charged battery fully yesterday afternoon, this morning would barely turn engine.

Started diagnostics, immediately found standing drain of ~1.25 A

Have disconnected everything - at least as far as schematic shows - and the drain is still there.

See the line I have high-lighted in red -

I validated that I have the correct cable at the fusible link end, by checking continuity to those fuse terminals (fuses removed)
So that cable is disconnected from the fusible link block and I have also removed the 30A Starter Fuse & also the 30A AM2 Fuse.
The 7.5A ALT-S Fuse is removed and the two high current cables on the other side of the 140A ALT fuse have also been disconnected.
The fusible link assembly with the main battery positive terminal is also unconnected.
Now - If I touch the cable which connects to those fuses (originally connected to the fusible link) directly to the battery positive, I get the 1.25A

So the big question is - where else is that going?
According to schematic, that line should be completely isolated when removing those two fuses.



post script
I also just found that if I touch the wire highlighted in Orange (that goes to the alternator) that also induces the 1.25A draw.

So I am suspecting an alternator issue - the question still remains where the connection on the 'red' line is going to complete a circuit through that wire?

Last edited by DEcosse; Nov 1, 2011 at 04:37 PM.
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Old Nov 1, 2011 | 05:26 PM
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Never Mind!

Beating my head against a brick wall all day & finally tested my meter.
It's not drawing that much current at all.
(I had wondered why no spark at 1.25A)

Looks like it's just the battery after all that.
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Old Nov 2, 2011 | 08:15 PM
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Originally Posted by DEcosse
Never Mind!

Beating my head against a brick wall all day & finally tested my meter.
It's not drawing that much current at all.
(I had wondered why no spark at 1.25A)

Looks like it's just the battery after all that.
Always a big fan of an easy fix.
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Old Nov 2, 2011 | 11:32 PM
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That was my first reaction - the battery is going. This is exactly what happens when it does not take/hold the charge anymore. In my experience the LX needs a new battery every 5 years or so.
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Old Nov 3, 2011 | 08:50 PM
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Originally Posted by AKoch
That was my first reaction - the battery is going. This is exactly what happens when it does not take/hold the charge anymore. In my experience the LX needs a new battery every 5 years or so.
It all depends on the battery you get. When I lived in AZ, the heat would destroy most batteries in 1.5 yrs. The stock Panasonic battery, which lasts upwards of 6-9 yrs in benign environments like coastal California, lasted 3.5 yrs in AZ. I replaced it with an Odyssey PC1700 with full metal jacket. So far, I've gotten 4.5 yrs in AZ plus nearly 1.5 yrs in NM. Next time I replace a battery, I'll get the same brand. It's used by law enforcement.
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Old Nov 4, 2011 | 04:10 PM
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I used only stock panasonic batteries so far in the LX. Only a few month ago tried a cheap over the counter Delta brand. So don't know yet how long will it last. But certainly you are right, it depends on the operational conditions a lot.
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