Electrical/Battery Mystery???

[92LongBed]

I am truly baffled at this point. I recently became a victim to bad batteries. Both batteries were within 3 years of age but my truck is not driven daily so I expected a little less than full life on the batteries even though a good battery should be okay with no use for months if stored properly (so i've heard) anyway. I take both batteries to Autozone to have them charged since my truck is dead in my apartment parking lot. I receive both as in "good" condition and reinstall them and my truck starts. (yay)

the next day my truck will not turn over and it is even worse off than the previous dead battery start. So I take my ass to Costco and replace BOTH BATTERIES because I am fed up. I replace the "main" battery against the solenoid passenger wall first and the truck kicks on like nothing was ever wrong. Very strong start and I am happy. So I wait a few days before I go to Costco to return the 2nd battery since i'm receiving 12v on both with my multimeter.

Then I drive to Autozone again to take care of a few reverse light bulbs that had been to dim for my liking and as I am in the parking lot turning my truck on and off (electrical only no engine start) everything is working and dandy. I go to leave Autozone and my f*cking truck isn't turning over AGAIN.

Autozone Tech comes out with his multimeter, shows 0v on both my alternator and my older battery and i'm like what????????? so we charge the older non replaced battery, his battery tester shows 85% charge and he suggests my alternator is crap at this point. Well I get home and use my multimeter to gauge all connections on both batteries and to alternator and they're all reading 12v ignition off 13v ignition on. I've tested 3 separate times over the course of the last 7 days. Truck still runs fine and i'm receiving no power input issues as of today.

All battery connections are clean and batt cables are secured. Traced all wires to started and alternator all wires are in good shape.

I just dont know enough about the possibilities of bad batteries and their symptoms.

Is there another issue I could be overlooking or did the original autozone battery charge just crap out and i'm going crazy or can batteries slowly die over time and i'm just running one good new battery and one old half assed battery that is just still hanging on?

EDIT: i'm reading other some what simliar issues and people are suggesting a replacement for the positive battery cable harness. Maybe it is just time for that to be changed.

 

[ih8minimumwage]

Batteries need to be replaced in sets, otherwise the older battery will drain down the new battery trying to equalize the resting voltage.

I wouldn't call anyone working at Autozone a "Tech", you could be dealing with something as simple as the fender mount solenoid going out.

What's your charging voltage with truck running? Any chance you have a test light to check for a parasitic drain?

 

[DaveBen]

One way to look at these batteries: ONE battery in TWO places. If you replace one battery you should replace the other as well or you are doing HALF the job.

 

[IDIBRONCO]

Did your test give you 13 volts with the ignition on and engine running or was the engine not running? I'm asking because it would be odd for there to be higher voltage with an electrical draw.

 

[92LongBed]

Batteries need to be replaced in sets, otherwise the older battery will drain down the new battery trying to equalize the resting voltage.

I wouldn't call anyone working at Autozone a "Tech", you could be dealing with something as simple as the fender mount solenoid going out.

What's your charging voltage with truck running? Any chance you have a test light to check for a parasitic drain?

damn ok that makes more sense replacing both. I shouldve known that. Solenoid has power going to it but idk if that means a damn thing at this point. My voltage with the truck running is 13v. I checked both batteries + to - and it gave me 13v running then i tested each battery - to +(alternator) and those readings were also 13v

 

[92LongBed]

One way to look at these batteries: ONE battery in TWO places. If you replace one battery you should replace the other as well or you are doing HALF the job.

this makes sense, i will get a replacement this weekend.

 

[92LongBed]

Did your test give you 13 volts with the ignition on and engine running or was the engine not running? I'm asking because it would be odd for there to be higher voltage with an electrical draw.

engine off all my power readings were 12.5ish and engine on and running all my readings were above 13v

 

[IDIBRONCO]

13 volts is a little low. Ideally, it should be 14-14.5 or so volts. Mine usually stays at 14.2 volts.

 

[92LongBed]

13 volts is a little low. Ideally, it should be 14-14.5 or so volts. Mine usually stays at 14.2 volts.

Ah okay, well I need to replace the other battery so maybe that will button all of this up. I appreciate the replies. Thank you

 

[IDIBRONCO]

If not, you may have to look into your alternator.

 

[MtnHaul]

Since I'm assuming the OP still has the original style alternator--not 3g--I would say the charging voltage does seem low. Before I swapped out to a 3g alt I was still getting 14-14.4 volts with engine running even with old batteries. Maybe just the voltage regulator? I never had to trouble shoot the original system so I don't know if the voltage regulator dies slowly or just cr*ps out.

 

[BeastMaster]

Both batteries grounded properly?

You may be working the hell out of one battery while the one with a bad connection contributes little to none.

Maybe try disconnecting one battery's negative terminal and try a quick start attempt, reconnect ground and disconnect the other and try again.

Both start actions sound nearly identical? Or is one battery trying to do the job all by itself?

I have had a sneaky glow plug relay malfunction of sticking contacts send me on a wild goose chase on the battery bus. You know, unexpected erratic draining of the batteries when everything was supposed to be off. And destruction of my alternator.

Edit...upon review, I just discovered I responded to a stale post.

Sorry. My bad...I forgot about the "similar threads", and wasn't paying attention to timestamps.

 

[Old Goat]

Yeah I have done it too.
The OP should have come back and completed this thread what his final out come was.

But what you added, will help someone down the road doing a search on this problem.

I read similar threads also, lot of people don`t know they are there,


Goat

 

[92LongBed]

Both batteries grounded properly?

You may be working the hell out of one battery while the one with a bad connection contributes little to none.

Maybe try disconnecting one battery's negative terminal and try a quick start attempt, reconnect ground and disconnect the other and try again.

Both start actions sound nearly identical? Or is one battery trying to do the job all by itself?

I have had a sneaky glow plug relay malfunction of sticking contacts send me on a wild goose chase on the battery bus. You know, unexpected erratic draining of the batteries when everything was supposed to be off. And destruction of my alternator.

Edit...upon review, I just discovered I responded to a stale post.

Sorry. My bad...I forgot about the "similar threads", and wasn't paying attention to timestamps.

all good i set notifications on all my threads just incase i can answer any suggestions or questions. I ended up replacing my positive battery cable/harness and my truck cranks like new. So I think all along I just had deep corrosion in my positive cables and it was giving me poor power circulation to starter and batteries. Essentially assuming i replaced batteries for no reason. and i bought a powermaster starter thinking it was my starter failing but oh well. new shiny starter, 2 new shiny batteries and a brand new posi battery harness. i'm driving happily now

 

[92LongBed]

Yeah I have done it too.
The OP should have come back and completed this thread what his final out come was.

But what you added, will help someone down the road doing a search on this problem.

I read similar threads also, lot of people don`t know they are there,


Goat

Sorry new to the forum experience and I need to remember my threads can help too. Ill be better about coming back with the results and success of any issues I bring up here