btanchors

Greetings.

I have a 2003 GS430 - I am the original owner, 101,500 miles.

The original battery failed about 6 years ago - I replaced it back then with an Optima Red Top battery. Fast forward to December 2013. Engine started cranking slowly. The Optima Red Top battery was 6 years old, and although I didn't think that was particularly outstanding life for a Red Top Battery, I went ahead and ordered a new Red Top.

Installed it at the end of December 2013. The new Optima battery had a manufactured sticker on it indicating it was made in November, 2013, so it was a very freshly made battery.

Fast forward again to late April, 2014. I noticed the engine cranking well, but perceptibly slower than it did when the battery was brand new. Slower cranking, but definitely within the range of normal, and not enough to do anything about it.

Last week, I ran an errand during work, and when I returned, apparently I didn't shut the drivers door completely, it was slightly ajar. I assume this left the interior courtesy lights on. I was only away from the car for about two hours, and when I returned, I only got clicking sounds when attempting to start. Strange, I thought, I didn't think courtesy lights would drain the battery so fast, especially a new one. On the third attempt, the starter turned over, but *very* slowly, although the engine started. The VSC light stayed on, and pressing the VSC button didn't do anything. I figured it was the low voltage screwed some things up. I drove the 8 miles home, using lower gears so the engine would rev faster, hopefully that would help the alternator charge the battery up some. When I got home, I connected it to my 10 amp battery charger. According to the meter on the charger, it was charging heavily, but indicated the battery was fully charged only 15 minutes later. I thought that kind of strange, as if the battery was really that low, it should take longer to charge. Removed the battery charger, and the engine turned over very fast, like new. I figured everything was fine.

I took some time off this past Memorial Day weekend, drove home Thursday, put the car in the garage, and didn't attempt to start it until this morning (Tuesday, 4.5 days later). Engine started but cranked very slowly. I drove it to work, and again, this evening starting up to come home, the engine cranked slower than normal.

When I got home, I got my volt meter and charger out. Here are some readings and observations:

Battery reads about 12.5 with engine off.

With car started, it reads 13.65 at idle. No electrical accessories turned on. Accelerating the engine does not significantly change the reading.

Turning on a single electrical accessory, like the HID lights, or AC blower by itself, momentarily causes voltage to drop (for a split second) but voltage goes back up to about 13.6 in a split second. Accelerating brings it up to 13.65 - 13.7.

If I return the engine to idle, and really load it down by turning HIDS, rear defogger, and AC fan on high, at idle, voltage drops to 13.1. Accelerating brings it back to 13.6 at about 1500 RPM. When the radiator cooling fan kicked on, it went down to 13.5.

These results are pretty repeatable.

After conducting these tests, I turned the engine off, then connected the charger. It charges at about 5 amps for a few seconds, and rapidly goes to zero, indicating the battery appears to be fully charged.

From this, can I reasonably conclude the problem is the battery and not the alternator? It took a very heavy electrical load to bring voltage down to 13.1 at idle, and accelerating brings it right back up to 13.6. Operating only a single electrical accessory does not significantly lower the voltage, even at idle.

This Optima battery is only 6 months old, and is still under warranty. Could it really be the battery is at fault here?

ttaylor993

How about the obvious. If the battery numbers are ok, and the car has issues starting, how about the starter!

JJaySilver

I agree, it could be the starter. But 13.1 with everything on is really low for an alternator at idle.

GSGenesis

battery voltage with car off(looking for >12.6v), are the battery connections are clean/tight, and if the alternator produces 13.2-14.8 volts at the battery with the car running. Betting on a poor battery, connections, etc. If the alt does not produce at least 13.2 at ~2k rpms, then you have a bad alt

btanchors

All - more data:

1) I mentioned the VSC light was on after the first difficult starting incident. I forgot to mention that the light turned off and stayed off when the engine was shut down and restarted. The light has not come on since. No other warning lights are on - everything indicates normal.

2) The starter was replaced less than two years ago. I do not think the starter is at fault since it always turns over rapidly if the start occurs after the battery has been charged with my charger.

3) At 8:00 PM last night, I took a reading from the battery with the car turned off and no accessories running. It read 12.47 volts. This morning, at 7:00 AM (11 hours later), it read 12.33 volts. I do not think it is a parasitic draw, because I connected my battery charger after taking the voltage reading. The charger momentarily indicated it was charging at 5 amps, but then immediately went down to zero. So, the charger indicates it doesn't need charging. If it was a parasitic draw, It should have taken awhile to charge back up, since the battery would have been partially discharged.

I think the bottom line is the battery is not holding its charge. Unless someone else comes up with something to check, I'm going to try to exchange the battery for a new one. I will update this thread with the outcome.

burny

I would bet battery from my experiences with the GS300

GSGenesis

I'm telling you I just went through this, same exact scenario, I had orielleys check my battery and alt. and they told me both were good. Car hesitated at starts inbetween days WAY more than it should have. So I took the battery out, took it to them, and told them to charge it and check how it does, turned out, battery was donzo.... Replace it. You'll see. Unless your shorting somewhere which will drain your battery as well, or your voltage regulator is bad, which I doubt as well.

offbad

iTrader: (5)

you can try this:
have the car running and disconnect the negative terminal

if it stops, alternator
if it runs, not alternator.


also alternator should be putting out nearer to 14

bonesnj0

Check battery with Battery load tester, Then I would check all connections terminals and grounds.
I believe if alternator was bad voltage would not have came back after momentary drop.

btanchors

Here's the update:

It was the battery. The problem got worse over the last several days - Got to the point where even only a few hours after being shut down, the engine would turn over slowly when starting. Yet the charger indicated the battery was fully charged.

I exchanged the battery for a new one under warranty - it didn't cost me anything. Engine now turns over very fast. I am disappointed an expensive battery like an Optima would only last 5 months. The new one is also freshly manufactured, in April 2014. Hopefully it will do better than the last one.

Thanks to everyone for their response!

Cranix

Just to let you now checking a lead acid battery with no load on it is worthless. You can check voltage all day and it will read 12,13 volts on a bad battery. You have to put a load on it and watch the voltage drop. From
what you said above it looks like a bad battery. The bad starter is a possibility only if it was using excess current
killing your battery. You could have a parasite load from a faulty system draining your battery. You can check
it by disconnecting the positive lead from your battery and checking current draw with the car off or using a small
light. It should not light up.If it does you have current draw. Start pulling fuses tell you find it. Hope this helps.

TNSC

Where do you put the light? Between positive terminal and cable ? Are the Lexus (2004 LS) regulators internal or external ? Thanks!

Cranix

Yes. Hook one end to the positive terminal and the other to the positive cable you removed.
As far as the alt goes don't know for sure. I've worked on a lot of different models of cars over
the years and I haven't come across a external voltage regulator for a long time, except on pre 70's cars. Everything now days are internal or screwed on the side of the alt.

GSGenesis

Dam I'm so dam good..... And on top of that, (Combs hair) so dam sexy..... ******..... HAHAHAHAHAHAHAHA!!!!! Jk jk, glad we could help brotha, now another one bites the dust.