is it possible a battery can read 12volts but...

[Etac 10+ year member]

ok sorry for the noob question

but i just redid my system with my new amp and everything... i drove to maine from new jersey.. stayed there for a week drove back... anyway i've been back for like 2 days and went to start my car this morning, but it wouldnt start...

it defently seemed like a problem with the battery and popped the hood.. and the terminals were covered in that white corrosion crap... but they were clean a week ago.. so this all happened during this trip..

i tried jumping the car.. no luck.. i cleaned off the cables... tried jumping the car again.. and it very slwly kicked over...

i drove it around let it charge, everything worked fine... shut the car off... now it doesnt start again...

now the thing is, my whole elctrical system is acting funny... from how strong the fans blow.. locks wont work.. headunit wont even kick over... ect..

but when i check the battery with my voltmeter it still reads over 12 volts... but are odds this battery s dead or a problem possibly somewhere else?

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[jco1385 5,000+ posts]

dead cell. wont hold a charge.

and the corrosion could be loose cables

 

[Etac 10+ year member]

yeah i figured the connections were prolly a little loose, but i know they're fine now cause i checked voltage at my distro block in the trunk and it reads the same as the battery... and that cable is the last one on my terminal.. so im sure the connects before it (which is everything else) is seeing a clean connection...

 

[altoncustomtech 10+ year member]

It's absolutely possible... I've just replaced two different Orbital batteries //content.invisioncic.com/y282845/emoticons/mad.gif.c18f003ab0ef8a0d9c27ca78d77a6392.gif at $285 each because they wouldn't hold a charge right... they'd show 12+ but couldn't start a fire let alone the van... got an optima now and doing good... The tip to me is the corrosion that wasn't there before.... Most batteries i've seen that start that real bad have some internal problem and need replaced.... besides now would be a good time to have a worth while battery installed and do your BIG 3

 

[Etac 10+ year member]

well i had the big 2 done lol.. didnt redo engine block but it had a pretty decent connection already

 

[teen 10+ year member]

it isnt a good idea to drive around and let your alternator charge your battery like that. an alternator is meant to hold the charge, not charge the battery when and if it goes dead.

next time put the battery on a charger and then take the car for a ride.

it seems odd that the HU wont even turn on though. is the battery under warranty or what? how old is it?

 

[Etac 10+ year member]

i have no idea how old the battery is, its the same one that came with the car when i bougth it, but nothing is working right.. the power locks barely move.. my headlights dont turn on.. anything really... theres some power but barely any

and i dont have a charger so my options were kinda limited //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[teen 10+ year member]

i was just saying that puts a lot of strain on your alternator. i did it once too back when i first got my jeep with the stock alternator and stock battery, and i knew it wasnt good, but i wasnt home and had no other choice. once isnt gunna kill you, but i think you get what im saying.

try a new battery and see if that solves your problem. im pretty sure it will, because all these problems sound like the batteries shot.

 

[Vermithrax 10+ year member]

You say you cleaned the terminals, just the top? If the corrosion is between the terminal and posts it can cause the car not to start, yet the voltage still read fine. If you didn't already, take the terminal off and clean the inside until it's shiny, same with the posts. If you still have problems, you probably need to charge the battery up good and have it load-tested. No need to replace the battery unless it's absolutely necessary.

 

[Etac 10+ year member]

alright ill try cleaning them one more time.. see how it goes

 

[altoncustomtech 10+ year member]

I agree... make sure the terminals are completely clean.... Then take that thing to Autozone to test the alternator as well as the battery make sure your whole system is operating properly and they'll be able to tell you for sure whether that battery is good or not and the alternator if its getting weak.

 

[NoPh33rRaCiNg 10+ year member]

You say you cleaned the terminals, just the top? If the corrosion is between the terminal and posts it can cause the car not to start, yet the voltage still read fine. If you didn't already, take the terminal off and clean the inside until it's shiny, same with the posts. If you still have problems, you probably need to charge the battery up good and have it load-tested. No need to replace the battery unless it's absolutely necessary.

x2 i was having the same problem with my girls acura after i installed an amp and sub, the terminals were always corroded, if you twist the connectors on the post, you can sometimes find a sweet spot because it grinded away some of the corrosion, go to napa or schucks and buy some anti-corrosion spray, shit sprays out purple, and use a wirebrush and scrape the inside of the connectors and scrape the terminals, corrosion causes a barrier between the metals so the car doesnt start

 

[Etac 10+ year member]

well i went out this time with sand paper and cleaned em off as good as i could and she started right up so yeah i guess thats all it was... i just figured when i cleaned em before it was good enough and since it was reading 12v that power was getting through, obviously i was wrong.. thanks for your help guys

 

[Vermithrax 10+ year member]

NP, I love it when it's a simple fix. You were reading 12v because the system was idle. The corrosion as was stated created a barrier that prevented the amount of current required to engage the starter. If you'd had a DMM connected, it would have dropped from 12V to nothing when you turned the key.

 

[atoz350 10+ year member]

NP, I love it when it's a simple fix. You were reading 12v because the system was idle. The corrosion as was stated created a barrier that prevented the amount of current required to engage the starter. If you'd had a DMM connected, it would have dropped from 12V to nothing when you turned the key.

That and he was probably taking the readings from the battery posts, before the corrosion.