Help with Intermittent low voltage light on 2008

[SteveT]

Took the 2008 Viper out for a quick drive last week. The starter sounded a little weak, like the battery could have used a charge. It had been sitting for a 6 to 8 weeks without a trickle charger on it so no alarms went off in my head.

Proceeded to drive into town, about 10 miles, pulled up to my destination and after sitting idling for a minute the voltage gauge drops to 10.5 or so and the red warning light in the gauge comes on. I rev the engine to about 2000 rpm and after a minute or 2 the voltage gauge begins to slowly climb back up to the normal 14 volt position. I turned it off and left it for about 10 minutes, got back in and it fired back up and everything was normal.

I decided to replace the battery since it was a little over 3 years old and at one point it was run completely dead, in my experience they are never the same after that. Installed new battery yesterday and went for a 25 mile drive. Stopped and let it idle for 5 minutes and all was ok. Drove back to the house and just as I was pulling into the garage the gauge starts dropping to the 10.5 and the light comes back on.

No other warning lights came on and it seemed to be running fine when the low voltage occurred.

Of course it is out of warranty by 65 days with a whopping 3,500 miles on her. Anyone have any thoughts on what is going on?

 

[bluesrt]

well i would say u got the alternater hot from it chargeing your battery and not shutting off soon enough and fryin the alternater, it happens

 

[Sonoman]

Once the alternator goes out, the voltage would typically drop steadily and not recover. It's a little odd that the voltmeter dropped suddenly. Would be good to put another handheld voltmeter right on the battery terminals (or the jump start terminals) when you see this problem-- make sure it's not just the dash gauge or its wiring. Also, a slipping belt could cause poor charging, though you might hear the slippage. I've had two alternators die on other cars, but they were not intermittent at all, just stopped working for good, causing a gradual discharge of the battery while driving. This doesn't mean your alternator itself is not intermittent; it can happen!

The intermittent part makes this one harder to troubleshoot. It's possible you just have a bad connection to the battery and vibration is causing it to come and go. A high resistance connection would cause a voltage drop at that point as the car attempts to pull current through the poor contact point (or damaged wire). Re-check the battery connections for tightness and that they are clean. It is true that attempting to re-charge a dead battery does stress the alternator, but I would expect a newer, low-mileage example to be able to handle that, unless this is a characteristic weak point on these cars. In any event, a sudden drop in voltage from normal operating to 10.5 seems more likely to be a bad connection, especially on a new, fully charged battery.

 

[Steve-Indy]

What they said...though I DO NOT assume that all new batteries are "good", nor do I assume that they are fully charged until I have done so BEFORE installation... having been burned on these points more than once !!!

 

[CitySnake]

Interesting you posted this Steve. I'm taking my 2008 to Tator's in the next few eeks for an oil change, et. al., and I've asked him to check out an identical situation with mine. If you don't get an answer, I'll post up my (Chuck's) findings.

I can't remember prior to this issue, but when you start up a cold 2008, does the charge light come on for a few (call it 5) seconds while the charge increases and then goes out? Mine does that now and I just never noticed it before.

 

[sssammm]

Ill bet my ole lady's wages its the alternator, ive had at least 6 go over the years

sam

 

[SteveT]

I normally charge all new batteries before I install them but this time I did not. I have it charging now and will take it for an extended drive tomorrow.

I plan on checking all the grounds and electrical conections I can find, are there any hidden cables/straps that I might miss?

CitySnake - I believe the light coming on for a few seconds is normal. Please let me know what you find out.

Thanks for the help guys.

 

[SteveT]

Just an update. After installing the new battery and charging it fully I have not had the low voltage condition occur again.

I have driven it several times with trips ranging from 10 to 50 miles over the last month. I had the air blowing on high and the lights on
just to put a load on it and all is well so far.

At this point in time I am thinking it was a weak battery.

 

[bluesrt]

Just an update. After installing the new battery and charging it fully I have not had the low voltage condition occur again.

I have driven it several times with trips ranging from 10 to 50 miles over the last month. I had the air blowing on high and the lights on
just to put a load on it and all is well so far.

At this point in time I am thinking it was a weak battery.

it will happen again- the new battery did not fix it, if your car fired up fine and the starter sounded good and strong, u have another lingering problem comeing and going, make shure your battery cables are tight and all other related pieces. you stated after your new battery install,it still did it,was the new battery that low on charge?

 

[SteveT]

The new battery was low but not sure exactly how low.

I have checked all cables/grounds and they are all tight and corrosion free.

Prior to all this starting, the car had not been driven for 5 to 6 months. Not sure if this had anything to do with it or not.

At least this gives me an excuse to drive it more often just to keep an eye out for the problem.

 

[bluesrt]

allways remember, if your battery is dead or super low, never jump the car and let the alternater just charge, for 1 it will never charge it fully, (u need a trichle to do that) and 2 you stand a chance of burning up your alternater cause it runs too long to get the battery up to your cars running standards.

 

[GreenVenom]

Just took my 08 out for a drive, been parked for close to a month with a trickle charger on it. Original battery. Went for about a 40 mile drive with A/C on everything is fine pull into my neighborhood and hear a ding look at gauges and voltage gauge has dropped down and red light is on drive about 1/2 block and light goes out and meter is normal, come to stop sign same thing after sitting go a few light goes out and meter reads normal. Pulled in garage, Checked belt, it is fine. Any suggestions what to look for? Didn't want to bother anyone today with a call for advise since it's a holiday P.S. Seems like unless clutch is as far to the floor as possible ignition will not work, doesn't seem like I used to have to do that before?

 

[Steve-Indy]

Check voltage at battery without tender being connected. Try load test if in doubt. You can have a fully charged battery out of our 2010 if you like.

Our clutch switches sound the same...but if you think that yours has changed, take a peek at it to see if it has moved on shaft or has a bad connection. It seems to me that you were worried about this earlier this year.

 

[GreenVenom]

Thank you Steve, It will be at least tommorow before I can check things out. I left the tender off when I put it up.

The clutch I'm not sure about, even though it had been awhile since I started it, it just didn't feel the same this time. Be checking that out too.

 

[SteveT]

GreenVenom - Sounds like yours is doing the same thing mine was a few months back. Happened to me both before and after the new battery . The good news is that after 500 miles it has not happened again. The bad news is that I never found out what the problem is/was. Just have been driving it a little more often and that is not a bad thing.

 

[supersnake]

Went for a spin on Sunday, Car is always on a tender. Had not started the car for a couple of weeks, Went for a 150 mile drive and It was Very hot outside and we were idling in heavy traffic, Same thing heard the ding and the gauge was reading 10.5 volts. Revved it up to about 1500 and the gauge went back to normal. It did this only at a idle and in traffic. Once we got moving we drove home 150 miles and there was no more issues. Have done some research into the problem, I was told by a reputable alternator repair shop that the new alternators have plastic brush holders and in excessive heat will make the brushes hang up, So I was told the computer will shut off the alternator briefly if it senses excessive heat and after there is more movement of air around the alternator to help it cool, It comes back on.

 

[the_postman]

I'm having the same issue as the OP and several others. Can anyone provide what the solution was? Did fully charging the battery truly fix the issue? I've tried 2 different new batteries and have the same issue with both.

 

[SteveT]

Other than supersnake's post above I don't think there has really been any solutions/reasons for the issue to occur.

After I started driving mine more often I did not have the issue again. After I replaced my battery at 3+ years it still occured a time or two but nothing since late 2011.

Just a side note, the original battery is still going strong in my 69 camaro.

 

[the_postman]

I already drive mine pretty regularly and keep the battery on a tender for the most part when it's going to sit for extended periods. But I didn't fully charge the new battery before starting it, so maybe that is part of the problem. I put it on the tender last night to get a full charge. I'm thinking I'll probably take the alternator up to have it tested in the next day or two.

This is just such an odd issue. Mine doesn't care if I rev the motor up (as supersnake did), the voltage stays where it is. Sometimes it's 14.5ish and then boom, it drops to 12 for no rhyme or reason. One day it took 15 minutes for it to drop, another 30 seconds and then one time it started and never climbed above 12. All are random and the next time it starts it may be just fine again.

 

[the_postman]

Well, I may have solved it tonight. My friend and I took the alternator out and over to Autozone (yeah, I know...) for a bench test and it checked out good. This won't tell if a diode is bad but it did tell me if it was the regulator and it said it wasn't. I realize bench tests aren't the end-all be-all, but I took this as a good sign. so then we started thinking about what has changed on the car recently. I put the ACRX headers on about a month ago and we were removing the ground wires when taking off the starter. So we look at the starter and sure enough, one of the bolts holding the ground was loose just enough to give the wire some play. We tightened it up and took it for a short test drive and all was good. Let it sit for a while, then took it out for a longer drive with no issues, then another drive and still reading regular voltage. SO, the problem MAY be fixed, I'm going to drive it a bit more this week and keep an eye on gauge to see how it does.