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My 3.5 yr old Sear Diehard Platinum battery slowly died since the summer heat came on here in Florida. Sluggish starting was mostly noted and it has finally failed to start the car recenlty. Note that all this time I've been using the A/C and playing stereo heavily.
I can jump start the car ok and up until just this week the battery will charge if I let the car idle in garage for an hour with no additional load. But now the battery will not charge at all.
I took the car to Sears and right off the bat the guy tells me its the alternator since this line of battery has a very low failure rate. This was said without even testing the charging system so I'm suspicious.
They run a test and said for sure it's the alternator: 13.1v at idle and it should be 14v. They put the battery on a charger and it took nearly 4 hours for it to charge. Note here they told be it was fully charged when they finished. They also gave me an estimate of $500 for an after market alternator installed. I of course said no.
Today ( 2 days after taking it to Sears) the battery is dead again. I measure the voltage from the alterator at 13.1 at idle, but it does idle low and its a 11 year old alternator. at 1500 rpms the alternator is putting out 13.7v.
If I pull the cables off the battery the car continues to run fine even at idle. If I run the rpms up some I can operate the A/C and radio fine without the battery. I've never seen a battery indicator light come on.
Now this seems to me the alternator is still working fine though a little low but still enough to charge.
I take the car out for an hour drive on the highway with no A/C or radio on and the battery is holding no charge...car won't start after I stop.
when my battery was going out earlier this year, i went to autozone and had one of the dudes check the charge. battery was low and suggested i get a new one. also mentioned that if you keep using a battery with a low charge that it'll start to affect the alternator and cause premature death!
Replace the battery and I think that should fix your problems seeing that a battery that is unable to hold proper charge will cause a high ripple voltage which in turn means bad battery also preventing your charging system to charge up to par. Also, like previously stated, running it like this for too long could cause the diodes in the alternator to burn out so just change the battery, 3.5 years is close to if not better than average battery life here in Florida.
Replace the battery and I think that should fix your problems seeing that a battery that is unable to hold proper charge will cause a high ripple voltage which in turn means bad battery also preventing your charging system to charge up to par. Also, like previously stated, running it like this for too long could cause the diodes in the alternator to burn out so just change the battery, 3.5 years is close to if not better than average battery life here in Florida.
I agree, the output of your alternator seems normal.
I run a Scangauge with the alternator voltage displayed and I see voltage between 13.1 to 14.2 all day long.
Do not replace the battery...yet. If that is indeed the cause. Buy one of these. www.pulsetech.com. It has brought at least 5 dead batteries back to life.
Thanks guys. I agree. The battery is definitely failing. A full charge only lasting 2 days is likeyly the battery. I pulled the trigger and installed a Durolast from AutoZone.
99 lexus rx 300 I need help here please. Battery light comes on and when I turn the car off will not start back up. But I waited a few hours and it started up again drove home wouldn't start back up. Called mobile mechanic guy he said it's the battery he took it to Auto zone battery is fine. Came back and said he thinks it's the starter. Now I had him to put the battery back in and I started my vehicle and it came on but battery light shows on dashboard. If I had to guess I think it's a belt?? Reason being when I turn the car on in the morning it makes a loud noise and a few minutes later it stops and that's pretty much my routine every morning especially when it's cold. I'm no mechanic I no NOTHING about cars!!! It's a 99 I bought it from a private owner in 2016 drives good just these last few days having problem with battery light coming on and starting up. So is it the starter or belt or could it be the alternator........"Please give info"
Hi Ymelton here is an cheap & easy way to monitor/test your battery and your alternator voltage, and charge a phone too. lol
I got mine online but may be available at local auto part stores.
PS- I keep mine plugged into my cigarette lighter at all times so I can monitor my voltages easy.
Also, I forgot to mention- my voltage is higher(2004 RX330) when first starting the car and as I drive it a while the voltage
can go down to as low as 13.3V and this is normal because it is automatically regulated.
It is hard to see because the sun is shining bright on it but here is my battery voltage- Key on but not started.
And here is my car with engine running showing alternator voltage.
Wrong forum but I’m sure your issue crosses over to our model as well. I don’t think I’ve ever seen a battery light ever come on because the battery is actually bad. It comes on when there is low voltage while the car is running which would point at an alternator or possibly a short/ bad connection somewhere. I have a WIFI elm327 OBD2 reader and run the OBD Fusion App on my iPhone. One of the features shows voltage. You can see voltage while the vehicle is running which would be the alternator or when the car is off which would be the battery. If the alternator isn’t putting out enough voltage the battery won’t charge.
Hello sorry for responding on the wrong forum.
yes the battery symbol comes on the dashboard after a few minutes of me turning on my car (because my car starts) but once I turn my car off it want start. So I'm not sure if it's the starter or alternator Have been googling and I'm still somewhat confused. But thanks for responding👍
A general rule is, a starting problem, is a battery issue. But if it's having trouble after it's started, then it's an alternator/charging issue. However it's not always a problem with the alternator or the battery. I would think a top of the line battery like that has a minimum lifespan of 3 years. I live in Utah and the temperature swings from the teens, like today, up into the low triple digits thru July and August. And even through those extremes, I usually get 4-5 years out of a quality battery.
Any auto parts company will test your battery for free. Just stop by and they can test it in the car. They can also look at the output of the alternator and see what kind of amps are reaching the battery. It's best to test the alternator out of the car. But if u have a GS400, that's not a job want to do unless your certain its the problem.
What's more likely causing your problem is the copper wires transferring current from the alternator to the battery, or the positive or negative main battery cables. I am sure it seems hot in Florida, but part of that feeling is the humidity. All that moisture in the air, can wreak havoc on a piece of exposed copper with current running through it. Look for an ugly greenish blue smootz growing on the battery terminals, or the end of any of that main battery wires. Sometimes you have to get a razor blade and cut some of the insulation off the wire, and see how the copper looks underneath. Try checking a couple inches from the terminal. And if the copper is still nice and shiny, it's ok, just use some electrical tape to repair where u made your cuts.
I have a feeling your going to find one of your battery cables is full of corrosion, and the battery doesn't have a good conduit to transfer power too and from the rest of the electrical system. Good luck
08-04-10, 01:01 PM
Bad battery or failing alternator?
