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I've heard about that 13V thing but was stated that it can happen for very short time after charging... i stand corrected if you say so , what i said was that i've never seen one
About the new battery, it seems it's in perfect condition and that your multimeter id OK, better rely on it than on nanocom readings...here's the discarge chart
https://www.aulro.com/afvb/images/im...015/06/112.jpg
Regarding the multimeter reading, I am reminded of the saying regarding instruments, Man with thermometer always knows the tempeture, man with TWO thermometers is never quite sure!!! :D
The thing with taking readings is use the same instrument over multiple readings. Yes. It may not read the same as your mates, but it will give you a consistent graph of whats happening, and that is what is needed to see what the item you test is doing.
The nanacom may read a few points lower than at the battery, but if used consistently will give you the graph of whats happening.
Cheers Scott
A battery with this voltage left for a few days will possibly be stuffed.Quote:
Originally Posted by Islandnomad
Quote:
Originally Posted by d2dave
Dave as soon as I new it was at 1.5v RACQ jump started me and I went for an hour drive and got it back up.
Still have no idea how it got so low though, didn't leave interior light on etc......bit of a mystery really?
Keep in mind: 1 hours drive wouldnt have fully charged it...Quote:
Originally Posted by Islandnomad
Assumption of a flooded LA battery: current take up of maybe 15a...
Crude calculation: if the battery was a 100ah battery - in that hour you only injected 15ah
You did say though in your OP that the vehicle had been sitting around for a few days.Quote:
Originally Posted by Islandnomad
So how do you know how long it was at such a low voltage?
Dave true, I can only assume it was around 12v and over 3 days went to 1.5v, can't really say how long it was at 1.5v as I haven't really determined how this happened.Quote:
Originally Posted by d2dave
So I have my new battery as a backup. Decided to do Aliens Load Test and the results are as follows via Multimeter only:
Leave everything connected with the motor off.
Check voltage reading. Was 12.57v attached and while running 14.6v
Turn high beam lights on for 5 mins.(high current load).(no spotlights)
Turn lights off and check voltage reading. 12.37v
This should help take any surface charge off the battery.
Be aware if it does have a dead cell it may not restart after this. Thanks for letting me know so that I could get the backup battery 1st.
Try to start the motor, if it does start shut it of fairly quickly and repeat 5 or 6 times.
Recheck the voltage reading. Started car quickly 5 times now at 12.63v
Start and see if the voltage rises to @14 when running. Yes it did voltage started at 14.35v and rose steadily to 14.44v.
Also check the voltage when running with the head lights on. 14.36v
I then turned car off and voltage was at 13.45 attached so unattached it and it was at 13.06v, then checked it attached again and it was at 12.92v, so left it attached.
I then tried sierraferrie's Parasitic Drain test. I think I have a 16ma drain. What does that mean? Sorry might have to redo this as I forgot to wait 1.5hrs for slabs. Will repost result in an hour or so.
I am not sure what parasitic drain is normal but 16 milliamps is nothing to worry about.
This equates to 1 amp every 62 hours, which is roughly 2.7 amps per week.
If you have a 110 AH battery and your car sat for two weeks without starting
you would have a loss of 5.4 amps. No big deal.
If ECU's are going to go to sleep and reduce this, even better.
+1^^^ no worries about parasitic drain, that battery seems OK for now, check if your alarm sounder is working on volumetric alarm or not cos the only thing which comes in my mind right now about what could have drained that battery so bad in 3 days is that maybe the volumetric alarm was triggered few times by something and it doesnt sound to observe it if you dont watch the hazards and that might be the cause
so leave a window opened, lock it, wait untill the alarm led settles down then reach within the car with your hand and make some movement(dont open the door)... if no sound this way open the door to see what happens...if the alarm doesnt sound we'll speak then
Having thought this through, and now that the battery seems ok, I'll provide a little more detail.
The last couple of weeks prior to the "Drain to 1.5v" issue I have had another flat battery as well as a near miss.
What happened was that my gf said to me after we got home one night, 'is your interior light supposed to be on and I said yes and that they time out after a few minutes. She noticed a fair few hours later that the interior light was still on, told me and I went and turned it to the off position it was the front light only from memory". The car was labored in starting the next day but started so a near miss.
Then a couple of days later, I went to start the car and it wouldn't start, no dash lights at all. I put it on my charger, but the battery mustn't have been below 7v and my charger charged it up again no problem. No interior light issues evident. Can't really explain why this discharge occurred at all.
Then I had the big drain event and I hadn't used the car for 3 days which is unusual. I did consider the interior light as the cause, but I discounted it as once I had RACQ start the car, I was very careful not to touch things like interior light switches etc, as if it were left on, it would be on once started, I didn't touch any of these switches etc for at least the 1st week deliberately, and have not had any problem with interior lights since. The interior light in the front middle and back were not on when RACQ started the car. However I do note, that somehow an interior light has caused a battery to discharge once before this event, at least.
Is there an issue with any of these interior light switches with say corrosion, that leave them on beyond when they are supposed to timeout? As this could be a reason that the battery was flattened, grasping at straws here.
I'll also try the volumetric alarm tomorrow.