Now this is perplexing....."Battery not charging" warning, but finding the fault....not so good....

[Meghan54]

This morning, around 6AM, 30F outside, I start the truck up, an '03 Silverado w/5.3L V-8, and the driver info. center says "Battery not charging" on my dash. This warning lasted ~5 sec. then disappeared.

Fearing a failing battery or alternator, I first drove home (this was at a store about 1mi. from the house when this happened) and hooked up my battery charger. It read a 65% charge on the battery. After a few hours on 15A charge, it said it was 100% charged.

Then, not leaving the alternator's condition to chance,took it to Advance Auto and had them test the alternator....checked out good.

Then had the battery checked. Says it's good but needed a little charge....it measured an 85% charge from this 1 mile drive to AAP and back after it was at 100% charge immediately before returning to AAP and its testing on the battery.

So, alternator is "good" and battery is "good", although something's not right. I'm really thinking it's the battery.....4 years old, a cheaper brand.

Honeslty, haven't had elect. problems at all with the truck. So, where'd you dive into first? I'm really leaning towards the battery slowly failing, but the alternator's age is unknown.

Damn, I'm sorta stumped. First inclination is to buy a battery, but at over $150 for the battery, it's not a cheap proposition. Neither is the alternator, but at least it's a tad cheaper than the battery.

In a quandary right now. What direction would you go?

 

[NutBucket]

I don't trust bench testing. It gives you some idea but something has got to give. If the output of the alternator measures normal my first guess would be the battery is starting to go. How old is the battery and you might as well buy it at Costco if that's an option.

 

[Yuriman]

Where do you live? It's been brutally cold in most parts of the country and that causes all sorts of odd battery behavior.

 

[dave_the_nerd]

I would also be looking to replace the battery - seems like it's discharging too fast. Costco has the one for your truck @ $90.

 

[NutBucket]

And the warranty is great. Apparently places like Pep Boys only do warranty replacements if the battery fails their tester. Costco could give two hoots less about a test. Warranty applies, no questions asked.

That said, the last battery I bought was a Bosch AGM from Pep Boys!

 

[PowerEngineer]

FWIW, I'm a bit skeptical of measurements of a battery's charge. I wouldn't necessarily take the 100% and 85% measurements at face value, especially as those measurements were made by different devices.

If you are parking your Silverado outside, then it might be time to replace a four year old cheap battery regardless of whether or not it is really the source of your problem. I agree with NutBucket on Costco being the way to go.

Most newer alternators come with the voltage regulators built into them. Did Advanced Auto check just the alternator, or did they test the functionality of the voltage regulator too? If the voltage regulator is a separate device in your Silverado, then get that checked too. If either are bad, then I'd replace both.

It also might be worthwhile to check the tightness of your battery cables and ground straps. You might also want to check your belts; a little belt slippage on startup could cause the problem you have described.

Good luck!

 

[sdifox]

battery is probably on its last legs

 

[crashtech]

Regulators are all internal these days, afaik. A simple DIY check is to start the vehicle, then turn on a bunch of high current stuff, rear defog, headlamps, blower moter, etc. Check the battery voltage with the alternator working to supply these loads, and if you still have voltage over 13V, you are probably okay on the charging side.

Also, battery terminals should have regular maintenance, pulling them off and wire brushing them wouldn't hurt as a first step. Sorry if that's overly simple, didn't see it mentioned in the op.

 

[Meghan54]

Thx for the replies! I do appreciate it.

I'm really leaning towards the battery, myself. Just wanted to get a feel of others' opinions on this before spending $200 on an Interstate.

As for the devices measuring the voltages and charge state, as mentioned previously, the measurements mentioned were from the same device. AAP did measure it, but really showed little difference from mine.

It has been cold down here.....I'm near Anderson, SC. NE corner of GA, just off Lake Hartwell. An hour from Clemson and Athens. Been in the mid-20's most of the past week or so, with a few days hitting the teens at night. And the battery that's in there is an AAP Autocraft Gold, which just ran out of replacement warranty 4 months ago. Hated buying it, but was in a pinch.

The cables are tight, btw. I am a tad compulsive with doing checks on the truck at least weekly. That was one of the first things I checked. Nice and tight.

Costco would be an option, except the closest one is 65 miles away in Greenville, SC. Next closest is Buford, GA (Mall of GA west of ATL) at 75 miles. Hate to make a 130-150 mile round trip just to buy a battery....certainly won't be using them to regularly buy gas.

So my choices are Advance Auto parts, O'Reilly's, a local shop with Interstate, WalMart, and a NAPA with the rudest, know-it-all staff in existence, that I'll never set foot in again.

Choices are limited, so guess going to splurge on the Interstate. The other choices are just more of the same crap.

C'est la vie.

 

[sdifox]

If it was the alternator your car won't run. The lights and electronics would go wonky while you are driving and eventually the car dies.

Ask me how I know :awe:

 

[mindless1]

Costco would be an option, except the closest one is 65 miles away in Greenville, SC. Next closest is Buford, GA (Mall of GA west of ATL) at 75 miles. Hate to make a 130-150 mile round trip just to buy a battery....certainly won't be using them to regularly buy gas.

So my choices are Advance Auto parts, O'Reilly's, a local shop with Interstate, WalMart, and a NAPA with the rudest, know-it-all staff in existence, that I'll never set foot in again.

Choices are limited, so guess going to splurge on the Interstate. The other choices are just more of the same crap.

C'est la vie.

The Walmart Everstart Maxx line is pretty good, probably about $95 for the 850CCA version, depending on the group size it uses. They're made by Johnson controls, same as some of the Interstates (others made by Exide).

Easiest DIY test of the battery and alternator is let it idle for a minute while you get out a multimeter. Voltage on a battery with a fair amount of charge in it ought to be near 14.0V if not higher. After some driving, leave the vehicle off for at least a few hours and measure voltage in the off state. It should be near 12.6V.

I'd get the battery because even if you need a new alternator, that extra strain on a mediocre aged battery is going to mean you'll need a new one soon enough anyway, won't be wasted money like a new alternator would if you guessed wrong. Then again, meh a 16 year old alternator could go at any time too, lol you just have to expect aging vehicles to nickel and dime you.

 

[Meghan54]

Well, wife took it to work. The drive has about 30 min. of straight 60mph run in it, out of 45 min. of driving time.

Drove out, sat 12 hrs., then drove back. Checked batt. with both multimeter and charger's testing function and battery had 12.6V, after sitting 4 hrs. in 32F. Charge, tho, was reported at 80% by the charger.

Guess a battery is in the cards. Suppose the alternator is probably past due on its expiration date. But neither look ready to expire tomorrow, so there's that. I just hate working in the cold....better temps later this week, like the 60's.

 

[pcgeek11]

There are many places that will install the battery free with a purchase.My local Costco does it and Autozone and Advance Auto does it.

 

[mindless1]

^ Walmart too, if it's one of their supercenters with the service bays. Question I always wonder is are they going to hook up a temp battery to preserve my radio/clock and other various volatile memory. If not then I'd as soon DIY and do that.

 

[jlee]

At 4+ years I'd replace the battery at any hint of electrical weirdness - it's about time anyway.

If it was the alternator your car won't run. The lights and electronics would go wonky while you are driving and eventually the car dies.

Ask me how I know :awe:

It'll run for a while (until the battery doesn't have enough in it to keep everything going). You could have a dead alternator and simply replace batteries as they die and keep driving indefinitely.

 

[mindless1]

^ If for a while you mean maybe a single-digit # of miles on an already weak battery. It happened to me too, had a vehicle that started fine, nothing unusual noted, no problems with the battery or alternator prior to that.

Drove fine for a little under 2 miles, stopped at a gas station, turned vehicle off and 3 minutes later it wouldn't even come close to starting.

Got a jump start but had assumed it was the battery so only jumped it long enough to start it, not put much charge into it, so barely made it two miles back home, dash lights for unrelated electrical systems going crazy the whole time. Granted it was night so my headlights were draining it too.

 

[sdifox]

^ If for a while you mean maybe a single-digit # of miles on an already weak battery. It happened to me too, had a vehicle that started fine, nothing unusual noted, no problems with the battery or alternator prior to that.

Drove fine for a little under 2 miles, stopped at a gas station, turned vehicle off and 3 minutes later it wouldn't even come close to starting.

Got a jump start but had assumed it was the battery so only jumped it long enough to start it, not put much charge into it, so barely made it two miles back home, dash lights for unrelated electrical systems going crazy the whole time. Granted it was night so my headlights were draining it too.

I got lucky, it died 200 m before I went on highway...it was dark too.

 

[jlee]

^ If for a while you mean maybe a single-digit # of miles on an already weak battery. It happened to me too, had a vehicle that started fine, nothing unusual noted, no problems with the battery or alternator prior to that.

Drove fine for a little under 2 miles, stopped at a gas station, turned vehicle off and 3 minutes later it wouldn't even come close to starting.

Got a jump start but had assumed it was the battery so only jumped it long enough to start it, not put much charge into it, so barely made it two miles back home, dash lights for unrelated electrical systems going crazy the whole time. Granted it was night so my headlights were draining it too.

I have a buddy who drove hundreds of miles home by stopping at a store, buying a bunch of batteries, and swapping them out as they died.

 

[mindless1]

^ I suspect his alternator was not completely dead, either that or a very old vehicle without EFI and ignition.

 

[jlee]

^ I suspect his alternator was not completely dead, either that or a very old vehicle without EFI and ignition.

Nope, it was a 3rd gen MR2. Remember, we're talking about putting a fully charged battery back in -- not relying on what little is left in the battery that has been inadequately maintained by a failing alternator.

 

[Meghan54]

I have a buddy who drove hundreds of miles home by stopping at a store, buying a bunch of batteries, and swapping them out as they died.

Wonder what his miles per batt. worked out? Inventive way to get home, and it works.

 

[Pick2]

Your battery probably has one weak/bad cell - that's why it's dropping from 100 to 80%
New battery should fix you right up.

 

[Meghan54]

Well, now, guess new batt. is in order, but alternator failed this morning when I started the truck. Idiot light stays lit, batt. not charging on my info. center display, and voltmeter shows just 12V.......and then it suddenly started putting out its proper ~14.7V, then drops to 12V, then jumps back to 14V, all while the headlights dimmed considerably at 12V and back to normal output at 14V indicated by my dash gauge.

Figure it's the voltage regulator that was the actual failure point. Alas, being internal, the alternator was pulled and changed.....just before it began to pour. Thank goodness I decided to go put gas in the truck this morning and got to observe the behavior.

 

[NutBucket]

I have a buddy who drove hundreds of miles home by stopping at a store, buying a bunch of batteries, and swapping them out as they died.

#roadkill ? LOL

 

[dave_the_nerd]

Well, now, guess new batt. is in order, but alternator failed this morning when I started the truck. Idiot light stays lit, batt. not charging on my info. center display, and voltmeter shows just 12V.......and then it suddenly started putting out its proper ~14.7V, then drops to 12V, then jumps back to 14V, all while the headlights dimmed considerably at 12V and back to normal output at 14V indicated by my dash gauge.

Figure it's the voltage regulator that was the actual failure point. Alas, being internal, the alternator was pulled and changed.....just before it began to pour. Thank goodness I decided to go put gas in the truck this morning and got to observe the behavior.

Cool. Congrats on your new alternator.