Hi everyone,

My car battery lasts maybe 10 days before being unable to start. Oreilly and autozone have tested my battery and starter and said it was good so I decided to try doing a parasitic draw test. When I have everything closed, the amp draw starts at 1.5 and then slowly drops to 0.5. Seems weird to me that it drops, so I had a friend stand outside and start the test while I sat inside. Once he touched the multimeter to the negative terminal and wire, I heard the cassette player making noises. Is this common?

I pulled the radio fuse (#16 on right hand side) and the amp draw fell to 0.05. Now my problem is I don't know what it could be. Cassette player? One thing to note is my right speaker still works but it seems like the cone came disconnected cause I hear a plastic clunk when I close the door or go over bumps.

One thing I found was the wiring diagram from: https://www.clublexus.com/forums/ls-...am-please.html but I'm not too sure how to read it and see what could be related.

 

That amp draw is fairly normal, these cars do not like sitting too long.

 

The original CD changer in my car - even with the car off for a period - just made a ton of noise unless I propped open the feed slot.

 

Hm is it really normal? We used to let the car sit for a month to go overseas and it would be fine.

 

It is only "Normal" as the cars age. It is really NOT normal, its an old car and the problems just creep up on you just like an aging person. You have to find and cure them.

 

Lock the car, and wait about an hour, it should only be around .25-.5 amps once everything shuts down. These cars still run the alarm and some other systems like the smart key system and if you leave it sit the manual shows you how to disable the smart key

If the battery ever got low enough to not start it's permanently weakened and if it was already old that doesn't help. If you don't have the smart systems and feel the radio is the issue then pull the fuze and see if it still dies/has draw but these cars simply have a lot of systems that occasionally take power when sitting.

 

Yeah I definitely understand that. I wish the wiring diagram I linked is easier to read. I pulled the radio fuse and I'm letting the car sit for a week to see if it'll start up. Then the next issue is how to figure out the draw from radio .


It is weird to me that when we connect the multimeter, amp draw starts at 1, drops to 0.5 while I still hear the cassette tape trying to take in a tape and then it drops to 0.05 once I pull the radio fuse.

 

Put a tape in it and remove the tape to make sure it's not confused. It's normal for it to drop like that since when you lock it the car shuts stuff off. My 460/430/A8 all stay around 5 and taper down to .3 after about 10 min once it's done closing all the AC flaps, setting actuators and alarms, charging the brakes, and all the other little things they do when you lock and leave the car. The A8 will actually fully sleep after two weeks, you need to manually unlock it and then it will wake up again

 

Update: I still have the radio fuse unplugged and left the car parked for 6 days. It started but really struggled today. The draw is still low so I guess this is just normal and we just forgot how often we used to drive the car.

 

If your battery has been repeatedly flattened, then that battery is damaged and needs replacing.
A draw of 0.5A is very abnormal and will completely flatten a 70Ah battery in 140 hours or 5 days, but you won't be able to start the car after just 2-3 days.
Normal static (ignition off, all doors closed) draw should be well under 0.05A which will give you well over 30 days before it won't start.
My 2004 car draws just under 0.001A even with the SmartKey enabled and drops to lower than my ammeter can measure when I switch that off.

You will need to fit the ammeter, then switch off the car and go drink a beer/coffee for 20 or so minutes before returning to see the "static" draw value.
After ignition off and especially after disconnecting & reconnecting the battery (which you have to do to fit the ammeter), the car does a whole load of maintenance items before it finally reaches it's static state.
As an example, if you switch off the ignition and just sit in the car, after about 30-40 secs you will hear the car do some air vent servo checks and such which is part of it's maintenance/shutdown routine.

I drained my battery on Friday after a long wait in a car park listening to music. Had to use a jump pack to get her started.
After that she ran fine all weekend and started without a hitch every time, but 3 hours of music with the doors closed and engine off (ignition in ACC position) shouldn't drain the battery that much.
Because of that I will shortly be fitting a new battery, but then my battery is at least 4½ years old so it's probably on the way out anyways.

 

I guess my concern with that is how do I get to the fuses that are inside if I need to lock the car and let it sit for an hour.

Maybe I should just leave it. I left the radio fuse unplugged and 6 days of sitting later, car almost didn't start. I'm barely a DIY guy so electrical stuff is a little beyond me.

 

I replaced my battery and on investigation found that one of the cells was low on electrolyte, below the level of the top of the plates.
On a battery tester it showed as OK even under a load test, but that low electrolyte will impact the batteries capacity and was almost certainly the cause of my not being able to start after 3 hours with the ignition switch on ACC.
I topped up the low cell and put it on charge and it now seems OK. It'll remain in my garage as a spare. The new battery is a Yuasa YBX5005

You should be able to open your car with the physical key even when the battery is flat.
It will only unlock the drivers door if the battery is flat but you can always get in.

 

Ah what I meant was that they say to unplug your multimeter before opening your door. If I let it sit for an hour with the multimeter on the battery to test load, I won't be able to open the door.