what's draining the battery? VDJ79 Landcruiser 2007 V8 4.5lt

Submitted: Saturday, Jan 28, 2012 at 14:00
ThreadID: 91511 Views:14519 Replies:13 FollowUps:7
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Does anyone know what might be draining the start battery on my cruiser please? Everythihg appears to be switched off, but when I connect the second of two wires (first being the starter motor) to the battery a tiny spark indicates that there is power flowing somewhere. Takes nearly 2 weeks with no use, to flatten the battery (which is 20 months old). Also think I damaged a relay while charging the battery, but don't know its' location. Even though battery is fully charged (12.4v) it won't start with out the aid of the second battery via the Projecta over-ride button. Help please! thanks.
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Mark

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Reply By: dbish - Saturday, Jan 28, 2012 at 14:48

Saturday, Jan 28, 2012 at 14:48
Easy just put an multimeter set on amps in the line that sparks. Then start pulling fuses one at a tim untill the current draw disapears. Some newer vehicles ive checked have had upto 250Ma current drew for the many Computer keep alive memories.
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Reply By: PeterInSa - Saturday, Jan 28, 2012 at 14:56

Saturday, Jan 28, 2012 at 14:56
Did the meter check, after I found the battery was going flat over time. turned out to be a dud diode in the alternator. The diodes can be replaced but easier to fit a new alternator.

Agree on the standing current though, ie clock, alarm system etc.

Peter
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Reply By: The Bantam - Saturday, Jan 28, 2012 at 15:07

Saturday, Jan 28, 2012 at 15:07
It might just be the battery is buggered, lots of things will "spark" when connected buy they may not draw continuous current.

If you have an electronic dual battery controller that will draw current but it will be bugger all.

If the battery wont start the vehicle when it is "fully charged" its probably "had the dong"

The age don't matter..if a battery has had it, it's had it.

Generally when batteries are near death all the properties of the battery go out the window, and one of those is self discharge.

You think you have damaged, what relay and how?

First point of action should be to put the battery on a good quality multistage charger and see how it goes......how long does it take to come up to "full charge" and how long does it hold charge , will it then crank.

cheers
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Reply By: Allan B (Member, SunCoast) - Saturday, Jan 28, 2012 at 15:13

Saturday, Jan 28, 2012 at 15:13
Hi Mark,

It is not unusual to observe a small spark when reconnecting the battery. It is usually caused by electrolytic capacitors (condensers) being charged-up and does not necessarily mean that a significant current will continue to flow after the initial charge-up. Only by connecting a milliammeter in series with the wire will you determine if current is being continually drained from the battery. A small current will normally be continually drained by a few devices such as engine management systems and radios but this should not drain the battery.

What causes you to think that you have a "damaged a relay"?

Your cranking battery may be faulty with a high internal resistance. It can still indicate voltage of 12.4 or more yet not be able to supply the current needed by the starter motor. An indication would be to connect a voltmeter with the engine not running and observe the voltage drop when the headlights are switched on. If the voltage drops by more than about 1 volt then the battery is faulty.




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Allan

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Follow Up By: Notso - Saturday, Jan 28, 2012 at 15:49

Saturday, Jan 28, 2012 at 15:49
12.4 volts is not fully charged, a fully charged 12 volt battery will be around 12.6 to 12.8 volts once it has settled down after charging.
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Follow Up By: Allan B (Member, SunCoast) - Saturday, Jan 28, 2012 at 16:28

Saturday, Jan 28, 2012 at 16:28
Didn't say it was Notso!

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Follow Up By: Notso - Saturday, Jan 28, 2012 at 16:46

Saturday, Jan 28, 2012 at 16:46
Never said you did, I was just passing on to the enquirer that his battery wasn't fully charged.
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Follow Up By: Allan B (Member, SunCoast) - Saturday, Jan 28, 2012 at 16:58

Saturday, Jan 28, 2012 at 16:58
Then why did you post it as a Follow Up under my post instead of as a Reply to the enquirer? You've been on here long enough to drive this system properly without confusing the issue.

In any case, in the context of the original post you are simply splitting hairs. It matters not whether it is 12.4v or 12.6v, Mark was simply saying that the battery was charged, not discharged. Your comment to correct him added nothing to the discussion.



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Allan

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Follow Up By: Notso - Saturday, Jan 28, 2012 at 17:07

Saturday, Jan 28, 2012 at 17:07
Well actually a battery at 12.4 volts is not "Charged" it would be probably around 75%.

The reason I put the thing in as a follow up and not a new reply was that it was relevant to what you were saying in your post as well. So please don't take it as a criticism of yourself but simply me trying to add a little to the discussion and explain that a battery at 12.4 volts is not "Charged"
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Follow Up By: ModSquad - Saturday, Jan 28, 2012 at 18:40

Saturday, Jan 28, 2012 at 18:40
Thanks gents that's enough of the "mines bigger than yours" contest. It's serving no purpose but to hijack the posters thread.

"Edited at the request of Allan B"


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Reply By: olcoolone - Saturday, Jan 28, 2012 at 15:47

Saturday, Jan 28, 2012 at 15:47
Don't be to concerned.... most modern vehicles will flatten batteries if not started over a period of time.

You starter battery is only rated at 60 to 70 amps per hour so a load of 200 milliemps per hour will draw nearly 5 amps per day..... times that by 14 and your using 70 amps.

Most common power draws are factory radio and clock.
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Reply By: Member -Pinko (NSW) - Saturday, Jan 28, 2012 at 17:48

Saturday, Jan 28, 2012 at 17:48
I have the same vehicle as you and over a week the cranking battery will go flat from fully charged.
I'll watch the thread.
Stan
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Follow Up By: Allan B (Member, SunCoast) - Saturday, Jan 28, 2012 at 18:05

Saturday, Jan 28, 2012 at 18:05
Standby time of one week is pretty poor. If this is all you can get from the vehicle with a reasonable (not necessarily new) battery then Toyota have designed a poor product.

Park it at the airport while you go on a one-week trip and it's call the NRMA when you arrive back at the airport!

Seems like a backup battery would be an essential.

This is one of the reasons that I like my 2002 Troopy with no fancy electronic systems, even though I have spent my life in electronics.

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Reply By: Member - Phil G (SA) - Saturday, Jan 28, 2012 at 17:57

Saturday, Jan 28, 2012 at 17:57
Do you run a second battery and if so, what isolator?
What other aftermarket electrical gadgets have you got and what source of power?

This thread will probably go nowhere unless you measure the current and disconnect a few accessories to see what is drawing power.

PS 12.4 is not fully charged :-)
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Reply By: Member - Old Girl - Saturday, Jan 28, 2012 at 20:08

Saturday, Jan 28, 2012 at 20:08
Have a look at the glove box light or something stupid like that. We just replaced our battery after 130,000.
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Reply By: Member - Bucky - Sunday, Jan 29, 2012 at 06:55

Sunday, Jan 29, 2012 at 06:55
Mark
12.4 volts, means that your battery is 50% state of charge or less, depending on what article you read, or who wrote it...Just Google "state of charge for lead acid battery" and have a good read.

Bang the battery on a charger for 2 nights in a row, checkk the voltage, and then drive it.
See what happens the next morning.

Check the voltage, if not 12.7v or 12.8 v, but 12.4v, then I would say the battery is history.
Also keep an eye on your auxillary battery, as it may go too !
Quite often one battery will carry the other, and it can be too much forthe Auxillary when a new battery is hooked up into the system

May no tbe 100% true, but that is what I have found

Cheers
Bucky

AnswerID: 476248

Reply By: gragra - Sunday, Jan 29, 2012 at 09:29

Sunday, Jan 29, 2012 at 09:29
Two ideas for you, the first is I am wondering if you have a caravan brake controller fitted? I had a 100 series with a Tekonsha controller that intermittently flashed the brake
Lights when parked (apparently it was a fault with them), that drained the battery over about two weeks. The second is a faulty power relay to the engine management system, the EMS sucks power if it does not turn off, you could probably check that by measuring the quiescent battery current.
AnswerID: 476254

Reply By: Member - Neil G (VIC) - Sunday, Jan 29, 2012 at 10:34

Sunday, Jan 29, 2012 at 10:34
Hi Mark, Not sure if this will be helpful or not but I had a similar problem in my 60 series toyota and I couldn't leave it longer than 3 or 4 days without being able to start it. It turned out to be the electric brake controller which was using a heap of power in standby mode. I discovered that by unplugging it the battery is well upto starting the engine even after sitting for quite a while. I have plans to change the wiring so that the controller is linked to the ignition switch which will mean I won't have to remember to unplug it all the time!
Cheers,
Neil
AnswerID: 476263

Reply By: Member - tojofixa - Sunday, Jan 29, 2012 at 12:07

Sunday, Jan 29, 2012 at 12:07
My thoughts,
Original battery 20 months old is probably getting near the end of its useful life.
I have a similar vehicle, bought new in July 2007, battery started going flat if the vehicle was not started for a week or more, after about 2 years. Recharged the battery several times to no avail. Replaced the battery with a new one and problem solved.
My suggestion, fit a good quality new battery.
Cheers,
Derek.
AnswerID: 476276

Reply By: Markthemilko - Monday, Jan 30, 2012 at 00:09

Monday, Jan 30, 2012 at 00:09
Many thanks for all your replies. I fitted another battery - and it started no problem! That might solve the other problem of what is discharging the battery (over 10-14 days) as well! Hope so anyway, but if not I'll pull the fuses out one by one. No light in the glove-box, nor any trailer braking device.
thanks again, much appreciated.
regards, Mark
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Mark

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