12v Battery drain

[Gohedo]

Have a 2012 Jazz FIT imported from Japan registered in UK 2023, only 50000 miles on clock, gorgeous car, loks like they make them better for their own market. Have a problem with the 12v Battery, after leaving the car standing for 3/4 days the battery is dead. At the moment it is with an auto electrician who has done a diagnostics test on the battery and everything is A1, charging ok, holding a charge, the alternator working fine, and showing a drain of 0.02 which they say is normal , the only thing that they could find was that the battery was a little on the low side(which would be right being as i just jump started it to get to the electricians which was only about 8 miles). So they charged the battery fully and left it overnight, when they tested it the following morning the battery had lost 1/2 a volt. They recharged it and left it 3 nights and the battery was just enough to start the car but very low.
Any ideas as to what may be causing the drain???

[guest334]

First off how old is the battery the makers all place a code or numbers and letters on the battery usually on the top .

Second point get your garage or mechanic to test for battery drain there a set process which will I'd the causes.
One you've solved this then think about trickle charger these are invaluable before colder days are upon us. I've used  the CTEK without any issues.

[Gohedo]

Thanks for your reply. The battery is 9 months old, can't tell you what the numbers/code is as the car is with the auto-electrician but will have a look when I get the car back. They did a drain test on it and the mechanic said it was a normal 0.02 drain.

[Lord Voltermore]

If they have done all possible tests on the battery condition  ,including cranking test under load  (which might require specialised equipment) and have measured a normal minimal parasitic drain  it does point to something drawing an abnormal load  that only becomes evident  after the car is locked up  and left.   Maybe a central locking  solenoid short circuiting.           I once had an opel corsa  that had an after market  alarm system fitted, which included an optional plug in motion sensor. (meant to detect if windows are smashed by a thief.)
The car battery would go flat quite quickly  .  When I unplugged this module I had no further problems  (the car battery lasted 12 years  ! )  The module  had its own flashing LED but I dont think this alone was enough to explain the excessive drain.  But maybe it was.   

[Gohedo]

Thanks for the suggestion, I will suggest that to them when I speak to them tomorrow

[Kenneve]

Gohedo, states his electrician considers a drain of 0.02 to be normal.
I assume he means a drain of 20milliamp.
The 12v battery capacity on the Jazz is given as 45Ah, so the battery would be completely flat in around 13 weeks and probably failing to start, much sooner.
Having said that,  perhaps a drain of 20milliamps is rather high?

[HertsHonda]

Was drain measured by ammeter in series with battery and vehcle wiring ?
Presume the other terminal of battery was connected to vehicle wiring.
If so then surely devices like clock, central locking, alarm interior light, boot light, auto idle stop and engine 'computer' might be drawing some current?
Was the battery the one from Japan (how many weeks to ship from Japan?) or was car shipped less battery and 'new' one fitted on entry to U.K.

[Gohedo]

In reply to your first point on how the drain was measured, I am not sure as it was done by a qualified auto electrician so can only assume and hope that he knew what he was doing. The second point regarding the battery, the company I bought the car from actually sent me a new battery (when the issue first started) to replace the one that was fitted to the car when I bought it and assume the original battery was the same battery that came from japan with the car.
 

[Brakballe]

20 mAH is a tad high but OK. Check all boot, interior lights. I would suspect a bad battery. Especially if it's a generic China crap brand with no date of mfg stamp OR if it has been drained completely and then sitting like that for days or even weeks OR stored in the shop for extended periods without maintenance, which is pretty common (NEVER accept a new battery over the counter without measuring the voltage first!!!).
Check the battery with a proper tool that also put a load on it for CCA etc.
Check the system voltage while driving, should be between 14.0~14.4v. Many cheap voltmeters out there you can just plug into the 12v outlet in the center console, some doubles as USB-chargers.

[madasafish]

20MA is the standard drain for a Honda Jazz.
The battery is FUBAR  Probably standing for months before shipping.

Buy a new Yuasa one on line  for under £80. My last one lasted 9 years.

[Brakballe]

Just do a CCA test under load when fully charged. The results will speak.