Battery question

[Redrig]

Hey all, my truck won't start today I didn't even get clicks.

Radio wouldn't even come on, and the dome light would barely come on.

I grab my tester my battery is reading 12.45 volts, yet it can barely even light the dome light I'm talking very dim, barely even on.

I took an Uber to work and didn't have much time to do troubleshooting.

So the question is does this sound like a connection issue? Or can a battery be reading 12.45 and be dang near dead?

Just trying to line up the strategy for tonight. Thanks in advance

 

[alldodge]

12.4V is 80% charged
Look for corrosion on the ground cable connection

 

[racerone]

Step #1 would be to clean connections.----If that fails have the battery load tested.

 

[Redrig]

W

12.4V is 80% charged
Look for corrosion on the ground cable connection

Step #1 would be to clean connections.----If that fails have the battery load tested.

Thanks for the chart , 80% you would think would still be able to run a dome light.

It must be some crappy connections / build up .

Thanks for the info

 

[bruceb58]

Put the meter on it and try to start it. See what the battery voltage drops to during the start. A fully charged battery with no capacity left will still measure ok with no load.

Better yet, buy one of the cheap load testers like they have at Harbor Freight.

100 Amp, 6/12V Battery Load Tester

Amazing deals on this 100 Amp 6/12V Battery Load Tester at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Not great but will give you a general idea.

 

[Redrig]

weird , I dont recall ever having a battery fail in this fashion.

I left it on a 2 amp charger all day , volts were in the high 12s at rest when I got home from work.

as soon as I turn on anything , and I mean anything. Headlights, dome lights , simply just open a door , the volts plumet down to 8 or 9 within seconds, but then after a minute or so it will rebound up to 12.5ish (thats the weird part)

It just simply cant take any load at all. forget about cranking a starter , the dash lights are too much for it.

seems like ones that have failed in the past for me , just wont charge up...... but This one charges up but cant power a dang thing .

Thanks for the help again folks .

 

[dwco5051]

weird , I dont recall ever having a battery fail in this fashion.

I left it on a 2 amp charger all day , volts were in the high 12s at rest when I got home from work.

as soon as I turn on anything , and I mean anything. Headlights, dome lights , simply just open a door , the volts plumet down to 8 or 9 within seconds, but then after a minute or so it will rebound up to 12.5ish (thats the weird part)

It just simply cant take any load at all. forget about cranking a starter , the dash lights are too much for it.

seems like ones that have failed in the past for me , just wont charge up...... but This one charges up but cant power a dang thing .

Thanks for the help again folks .

Was this after you cleaned and tightened all the connections? If not sounds like a corroded connection. Are you reading the voltage with a meter on the battery posts or from the dash gauge?

 

[Redrig]

cleaned all my connections and the volts measured the terminals with a multimeter

 

[dwco5051]

Never saw a battery do like that before. Sort of narrows it down to the battery having an internal fault.

 

[04fxdwgi25]

99% of the time on a battery w/ 12+ volts, if the lights are on and you hit the starter and get a click, and lights go off, it's a battery connection (or very commonly, the grounding lead between the battery, block and / or the body), or a severely shorted battery.

Put a meter on the battery terminals posts, not the clamps, and watch voltage. Stays at 12 V, connection problem. If it drops super low, battery is shorted internally.

Check all the ground wires at battery, block and bonding wire to the body for tightness and / or corrosion. Correct any problems if found. Also, check the wired connections that go to the battery posts. Sometimes the wire itself, before the clamp, is crap.

Pull clamps off battery and clean them and the battery posts with a battery terminal brush, apply a little grease to the posts and re-install the clamps.

Drove a wrecker for AAA for many years, so this is from experience.

 

[dingbat]

What you describe fits the scenario of a battery dying of an internal short.

My truck died the same death two summers ago

 

[Redrig]

New battery and all is well now .

That was a learning experience for me for sure . That battery went from fine to less power than a watch battery literally overnight.

Thanks again all.

 

[racerone]

Drove my pick-up home one day for just over an hour.-----Tried to start it 20 minutes later and not a chance.----New battery solved it.

 

[bruceb58]

This is a standard way that a battery fails. It is especially true of batteries that have been accidently fully discharged once or twice. Starting batteries for vehicles have a lot of surface area on their plates. When a battery gets discharged like this, they sulfate which means a coating forms on the plates while the battery is severely discharged so your battery capacity gets extremely compromised.

Basically, the sulfation causes your once 70AH battery become a 1AH battery.

A 12V battery has 6 cells, if you drop a cell or have some sort of internal short, your max battery voltage would be one cells less voltage so around 10.5V with one failed cell....that was not the cause here.

 

[Redrig]

if you drop a cell or have some sort of internal short, your max battery voltage would be one cells less voltage so around 10.5V with one failed cell....that was not the cause here.

That's how most of mine have been taken out , can't get them charged into the 12s .

This one , by simply checking the voltage appeared to be just fine .

 

[bruceb58]

That's how most of mine have been taken out , can't get them charged into the 12s .

This one , by simply checking the voltage appeared to be just fine .

On this battery you just replaced, has it ever gone completely dead before?

How old was it?

 

[Redrig]

I dont recall it ever being ran all the way down before.

it was manufactured 5/14 , I live in Utah and I think our batteries last longer than alot of other states based on weather temps.

My Brother down in Havasu where its stupid hot has to buy one every couple years he says

 

[airshot]

Yes, heat is worse on a battery than cold !! But...keeping them charged and on a maintainer when not in use will help greatly no matter what the weather...

 

[flashback]

You got 8+ years, I'd want another just like it..

 

[airshot]

You got 8+ years, I'd want another just like it..

You never get two good ones in a row !!!