Replacing 10 Month Old Battery Today

[prix]

I will be getting a new battery put in today, but since the alternator is checking out fine, wanted to know what else could drain/ruin a 10-month-old battery. It's possible the battery was ruined by my driving habits (leaving the car sit for days, then taking short trips only when it was used), but I haven't ruled out a slow drain caused by an electrical or connection problem. So after I get the new battery in, I would like to get that checked out. Where would you start? Can someone knowledgeable post a sequence of 'do this, then this' step by step? Or is that even possible.

The one thing I know that is going on is the dash panel lights are going out. They flicker, sometimes are on, sometimes not. There is no backlight in the center console either (where the automatic shifter is), and I think the backlighting on the radio is out as well (not positive). The door locks work and the security alarm comes on (red light on in dash), and even when the dash panel lights are out, I can always see the icon that shows I need to replace a tail light, and I believe I can also see (there's an icon) what gear I am in. The windshield wipers work. The headlights/tail lights work. The seats power forward and back and the seats warm up. Haven't needed the AC in a while, but it always cooled when I needed it.

The one weird thing that happened a few days ago was, after taking the car out for a 30 minute drive (I was trying to get the battery to recharge itself before putting it away for the day), after I got home and pulled over, I heard a series of clicking noises under the dash panel (near the hood, in the center of the car) that lasted for four to five seconds. I had not heard that before. I heard it once again a little later (I drove off again to see if I could replicate the sound) for a few seconds then nothing since. Earlier that day, I had added a small amount (and I mean small, like a few tablespoons) of brake fluid to the reservoir, and did so while the engine was on idle. The owner's manual said if you have ABS that that is how you add brake fluid. I didn't add more fluids at that time because I realized I needed a funnel. Do brake lines run anywhere near that area? Could the sound be air working its way through? It almost sounded like a mouse doing a tap dance.

The other thing I wondered about is whether the air suspension was trying to 'lift' the car (it does this periodically when it senses more clearance is needed) but because of a weak battery, maybe it could not do what it usually does? I have no idea if the air suspension would even require power to function, but thought I would throw that out there.

1994 LS400 97K miles.

[curiousB]

Modern cars never actually stop using current from the battery. They drop to a very low power drain state called different things such as hibernation. The most common term is key off current.

This can be measured with an ammeter in series with the battery. It should be less than 50mA but for sure less than 100mA.

The with the car off and all lights and doors closed disconnect one side of battery (preferably the negative and run an ammeter in series. If you leave the hood open with this test check for a hood open switch and use a wire tie or something similar to spoof it into being closed just for the test period. Then wait 30-40 minutes to take a reading (cars don't instantly drop to low power state they gradually shed load items before they reach lowest power state).

Thats it. If you see current of hundreds of milliamps or more it suggest maybe a trunk, glovebox, or other light is always on and draining battery. Failing that, a bad alternator with leaky stator diodes can act as a vampire current path and gradually drain a battery (although this is fairly rare). To see if it is the alternator disconnect +positive wire to alternator and re-do the key off current drain test.

[1990LS400]

Also make sure that the battery terminals and cable clamps are spotlessly clean - shiny and bright. Use baking soda mixed with water to take off any powdery gunk and a wire "battery brush" to clean the battery terminals and insides of the battery clamps. After everything is cleaned up and reconnected, coat the battery terminals/cable clamps with a thin layer of petroleum jelly.

Of course, it is possible to get a bad battery that doesn't last long.

I thought the battery in my LS was failing in 2010 but all I needed to do was clean the terminals and cable clamps.

[prix]

I will print this and use to check things out. Thanks. I was just out and the car started right up. I called the tow/battery service and they said even tho the batt measured at 60% yesterday, that that's enough to start the car. If I get a good diagnosis on the electrical, then with a new batt I should be good to go for a time.

So test you describe is different from what AAA did last week? He hooked up jumper cables, started it, revved the engine several times, and eventually gave me a printout. Since AAA was done in 15 minutes (and what you describe involved a 45 minute wait), I assume you are describing a different test. The AAA printout said there were 'no problems' with the charging system.

Modern cars never actually stop using current from the battery. They drop to a very low power drain state called different things such as hibernation. The most common term is key off current.

This can be measured with an ammeter in series with the battery. It should be less than 50mA but for sure less than 100mA.

The with the car off and all lights and doors closed disconnect one side of battery (preferably the negative and run an ammeter in series. If you leave the hood open with this test check for a hood open switch and use a wire tie or something similar to spoof it into being closed just for the test period. Then wait 30-40 minutes to take a reading (cars don't instantly drop to low power state they gradually shed load items before they reach lowest power state).

Thats it. If you see current of hundreds of milliamps or more it suggest maybe a trunk, glovebox, or other light is always on and draining battery. Failing that, a bad alternator with leaky stator diodes can act as a vampire current path and gradually drain a battery (although this is fairly rare). To see if it is the alternator disconnect +positive wire to alternator and re-do the key off current drain test.

[prix]

Yes, this was done last week (cleaned connectors and posts), then again yesterday, when we had the batt out. He put a gadget on top of the posts and twisted. They are bright and clean. I noticed a small amount of corrosion at the base one of the terminal posts, and was kind of surprised by that since everything was cleaned off when we went through this process last week. He said it's possible the battery has a leak there. The only thing he didn't do was cover all with petroleum jelly when done. I can add that.

Also make sure that the battery terminals and cable clamps are spotlessly clean - shiny and bright. Use baking soda mixed with water to take off any powdery gunk and a wire "battery brush" to clean the battery terminals and insides of the battery clamps. After everything is cleaned up and reconnected, coat the battery terminals/cable clamps with a thin layer of petroleum jelly.

Of course, it is possible to get a bad battery that doesn't last long.

I thought the battery in my LS was failing in 2010 but all I needed to do was clean the terminals and cable clamps.

[jaswood]

The clicking you hear inside the center of the dash is more likely than otherwise the climate control system going through a COLD-START sensor and servomotor re-calibration. It only does that if the battery power is removed for a period of time. Has anyone checked the engine-chassis grounding straps?

Intermittently open cell within the battery will also sometimes yeild that result.

[prix]

I hope that is all that was. No, grounding straps have not been checked to my knowledge. I will add that to the list. Thanks.

The clicking you hear inside the center of the dash is more likely than otherwise the climate control system going through a COLD-START sensor and servomotor re-calibration. It only does that if the battery power is removed for a period of time. Has anyone checked the engine-chassis grounding straps?

Intermittently open cell within the battery will also sometimes yeild that result.

[prix]

Could having two tail light bulbs out over an extended period cause this type of drain? They are the two tail lights flanking (closest to) the license plate. I don't know how to change them myself, and planned to get that done the next time the car has to be in the shop. All the other tail lights are working.

[landar]

Could having two tail light bulbs out over an extended period cause this type of drain? They are the two tail lights flanking (closest to) the license plate. I don't know how to change them myself, and planned to get that done the next time the car has to be in the shop. All the other tail lights are working.

No, the burned out taillights would not drain the battery. An interior light like a vanity mirror left on would affect the quiescent current.

[jaswood]

Could having two tail light bulbs out over an extended period cause this type of drain? They are the two tail lights flanking (closest to) the license plate. I don't know how to change them myself, and planned to get that done the next time the car has to be in the shop. All the other tail lights are working.

Both in the trunk lid..... more likely means the cable harness in the driver side trunk hinge is compromised.

[prix]

@landar @jaswood -- ok, thanks. i'm not seeing any interior lights or anything staying on when i lock the car up. i think i will take it in to an electrical shop (along with my 'list') and have them give it a good going over.