Battery not charging

[tinmanSC]

I have two issues, they may or may not be related. This is a Lexus GS300, 2000. A grounding strap disintegrated last week. I was under the car, it looked like it was all ratty and broken. I touched it and it just fell away in my hands like dust on the driveway. It is the strap between the frame under the drivers seat and the transmission bell housing, not far from the starter. It was a green strap, maybe 1/2 to 3/4 inch wide and flat. Then this week, my battery will not charge. I can drive it, the car works great, all accessories are fine, but the battery will not recharge. It has slowly gone dead over the last few days. I noticed it a day or two ago, it was turning over slowly, then as the days went on it got slower and slower. Now it barely turns over at all. The voltage at the battery is low, it;s 10.2v with no load and the car off. If i turn on the lights that goes way way down, to maybe 7v or so, again with the car off.

 

[beast3300]

10V, 7V you probably have a bad cell in the battery. What is the voltage at the battery with the engine running?

 

[crazyoildude]

When the car is running and you put a voltmeter on the battery it should be around 13.5
If that checks out how old is the battery?
Also does it go dead when you are driving it or when it sits???
Let me know there there is another easy test to do with a volt tester..
Also replace that strap it could be an important ground strap for the trans

 

[wrcsixeight]

First of all, charge that battery, quickly. It is destroying itself sitting at 10.2 volts. 10.5 is considered fully discharged. An automatic battery charger might not even do it because the voltage is too low. You will then have to parallel a good battery to the discharged battery so the charger will recognize it as a chargeable battery. After a little while, disconnect the good battery so the full amperage of the charger goes into the depleted battery.

It is very possible it has a shorted or dead cell as well. If the battery is over 3 years old, consider just replacing it. It is rare for a 3 year old starting battery to rebound from a 100% discharge.

Second, replace that ground strap. It does not have to be a wide thick flat strap, you can get a short 4 awg insulated cable in any AP store for under 15 dollars. This ground might very well have been the main return path for the alternator current, without it, the other grounds had to take up the slack and might not have been upto the task.

You should also find and clean the other Grounds, like the battery to engine, battery to firewall, ect.

Clean the battery terminals too. Make the lead look like silver on the mating surfaces.

With a fully charged battery and all the above connections clean and tight, and if you are still not seeing at least 13.6 volts engine running, then you can attempt to diagnose other problems like voltage regulator, alternator, and any inline fuses in the charging circuit. Attempting to do so before eliminating the above items as culprits is foolish.

Also asking your alternator to charge a fully dead battery is bad for the alternator, and it will not do an adequate job of it unless you drive several hundred miles, and possibly not even then.

 

[tinmanSC]

The voltage with the engine running holds steady between 13.95v and 14.10v

 

[wrcsixeight]

Then your battery is shot. It likely has a shorted cell. Still replace that ground strap Asap.

 

[SIURXP]

A fully charged battery is 12.6 Volts NOT 10.5 volts.

Replace your battery.

 

[ahoier]

Definitely replace that ground strap.

Take the battery to Walmart, they have a diagnostic machine that can diagnose the battery. Just be warned, it can take up to 60-90 minutes for it to completely "test" and diagnose the battery.

Their machine can "breathe new life" into batteries that our household bench chargers can not

Likely, because the machine they use probably goes for $500 lol....a normal battery charger, is what? $80

Little price difference

 

[tinmanSC]

I cleaned the (remaining) grounding points (I found 4) and cleaned the battery terminals. It's running much better! The voltage is still ~14.1v when running, but after running the engine for a while on a short drive, the battery voltage while under no load and the engine off is ~12.75v. The slow starting issues seem to have been resolved, but this is just my testing this evening. I will retest in the AM.

 

[wrcsixeight]

10.5 volts is what you would expect a fully charged battery with 1 bad/dead/shorted cell to read. There is no bringing a battery back from a shorted cell. The fact that the headlights drop this to 7 volts from 10.5 is a sign the some of the other remaining cells have very high resistance.

Any device which forces a dead battery to fully charged in 90 minutes is severely abusing the battery. A battery cannot be load tested unless it is fully charged. Walmart does not want to have to replace any battery under warranty, so they pump a dangerous amount of amps into the battery in an attempt to see a green light from the load test machine, which only takes a minute or 2 to render a verdict.

It is true some severely depleted batteries do respond to a huge surge of amps. Even if it works, the batteries capacity has been reduced by the severe depletion, and then the intentional blast of amps.

A 100 amp hour battery should not really receive more than 20 amps, so a fully dead battery should not be recharged faster than in 5 hours. And once the 80% charged threshold is reached the battery can accept less and less, and as it heats up and can accept even less.

Winter's coming, just replace that battery. It is beyond redemption.

 

[wrcsixeight]

Originally Posted By: tinmanSC
the battery voltage while under no load and the engine off is ~12.75v. The slow starting issues seem to have been resolved, but this is just my testing this evening. I will retest in the AM.


Well perhaps the battery does not have a shorted cell with those voltage readings, but 12.75 after a short drive is just the surface charge voltage. I would be surprised to see it over 12.0 in the morning.

Put it on a regular battery charger overnight. Borrow one if you have to.

 

[morris]

get a really big ground cable. be sure it is black in color, as the electrons know what color the cable is. tongue in cheek, lol

 

[tinmanSC]

Originally Posted By: morris
get a really big ground cable. be sure it is black in color, as the electrons know what color the cable is. tongue in cheek, lol


I heard they only travel through blue cables or OEM cables. Is this false? It has to be true, all the after market grounding kits for the GS300 are blue. This must make the car go FASTAR! One would assume that it's the blue making the car go faster, not the better grounding.

 

[wrcsixeight]

To mitigate the increased wind drag with a big thick insulated blue or black round Ground strap(it is in the underbody slipstream right?), you will need to apply several coats of wax that contains PTFE.

I have used blue wires running under my vehicle and noted 2 second faster 0 to 60 times and a 25% improvement in MPG. But I installed a tornado and fuel line magnets at the same time too so it's hard to say whether the blue wires or the magnets had more effect.

Tis no joke!

 

[mechtech2]

Of course, replace that strap.
Clean where it seats nice and shiny, first.
This applies to every other ground and hot lead that you have.
Kinda tedious, but you have to do this and have it right to expect anything else to work OK.
Sure, you may have a bad battery or alternator, or both, but you should start here.
Then make your voltage checks off and running.

 

[tinmanSC]

Originally Posted By: wrcsixeight
To mitigate the increased wind drag with a big thick insulated blue or black round Ground strap(it is in the underbody slipstream right?), you will need to apply several coats of wax that contains PTFE.

I have used blue wires running under my vehicle and noted 2 second faster 0 to 60 times and a 25% improvement in MPG. But I installed a tornado and fuel line magnets at the same time too so it's hard to say whether the blue wires or the magnets had more effect.

Tis no joke!

Was this before or after you locked your A/C into the on position to get more power from the colder air coming out of the vents? Also, I read your post on straight 140 weight LSD gear oil in the crank case. It will brilliant.

 

[tinmanSC]

I checked it this AM. This is what i found:
Voltage of the battery alone with engine off and no load is 12.7v. Put any load on it, and it drops right away. I was getting 9.3-9.7 with just the running lights on and the cabin air fan blowing. I can start the car (turns over slowly, but it does start) and the voltage jumps immediately to 14.1 and holds between 13.95-14.10 no matter what electrical load I put on the car. I know that I need to replace that strap, and I will do it today or tomorrow. But does this sound like a grounding issue to you? Maybe it's hard to say. T-shooting electrical issues over the Internet is probably a pain.

 

[brianl703]

No, that is not a ground issue, that is a "battery is bad and needs replaced" issue.

 

[wrcsixeight]

Originally Posted By: brianl703
No, that is not a ground issue, that is a "battery is bad and needs replaced" issue.


x2. I happen to have a digital battery monitor for my Solar system. It displays and counts Amp in and out of the battery and displays voltage. Here is a story of 3 equal size/make/age Walmart dual purpose batteries.

One time@ 13 months, I noticed the voltage was lower than it should be. I unparalleled the batteries and found one was 12.7 volts, the other 10.5. Shorted cell.

A while later(@ 29 months), I noticed a similar problem, but only while under load. I separated the batteries and both read 12.6. I then applied an 18 amp load to one and it dropped to 12.3 volts. I applied the same load to the other and it dropped to 8.7 volts. When I removed the load the battery rebounded to 12.6 volts within 5 minutes. Very high resistance across one or more cells.

This left me with one of the original 3 batteries(now at 39 months), and I moved it to my engine compartment and have stopped cycling it. It is failing in the traditional manner. Shortly after driving, or fully charging with an outside source, the voltage drops to 12.3 volts. It can still turn my engine over, but it is ticking.

Replace that battery!

 

[tinmanSC]

Well, I have some good (or bad, depending) news. I replaced the grounding strap and all is well in the world again. The battery seems ok. I didn't have it tested, but it is once again reading at 12.5v while under load (lights on, cabin air fan blowing) without the engine running, still 14.10v with the engine running at idle. The engine starts just fine with nothing noteworthy to report. I will give it a try in the morning and see if everything holds.