Will a bad battery show low voltage?

[Dieseldad97]

Yesterday the truck started slow, looked at my voltage and it was lower than normal. Back when my alt. went out the tach stopped working, but now it works fine.
I removed and cleaned the terminals charged the batteries over night and it's still not showing the regular 14 volts. Can a dead/faulty battery cause my volt readings to be low?

I'm going to do a load test later on tonight.

Anything I'm missing here guys/gal?

Thanks for reading.:smile5:

 

[NVW]

Yes it can, what is the voltage? Also a bad cell will drop peak volts by 2v

Leo

 

[Matt Bachand]

Yesterday the truck started slow, looked at my voltage and it was lower than normal. Back when my alt. went out the tach stopped working, but now it works fine.
I removed and cleaned the terminals charged the batteries over night and it's still not showing the regular 14 volts. Can a dead/faulty battery cause my volt readings to be low?

I'm going to do a load test later on tonight.

Anything I'm missing here guys/gal?

Thanks for reading.:smile5:

Of course Good idea with the load test.

 

[Dieseldad97]

Yes it can, what is the voltage? Also a bad cell will drop peak volts by 2v

Leo

Not really sure the exact reading, it's a little over the 1/4 mark on the gauge.

 

[mfgguru]

What is it with us and starting/power issues? Must be a southern Manitoba thing!):h

A poor battery will cause you problems, but so will poor connections.

If you replace a battery, do both right away.

Mike

 

[Dieseldad97]

What is it with us and starting/power issues? Must be a southern Manitoba thing!):h

A poor battery will cause you problems, but so will poor connections.

If you replace a battery, do both right away.

Mike

Maybe I shouldn't have popped by your house LOL. Seems to be rubbing off..

 

[mfgguru]

Naw, it wasn't me!

 

[Dieseldad97]

OK. Problem fixed. Did a load test and found one battery dead using the top post for testing. When I used the side post, it checked perfect. Seems the top post is a bit loose and I guess the battery lost all connection there.

I'll be looking for a new battery or batteries I guess.

Thanks for the help guys.

 

[iamdave0887]

when I had one battery go bad after jump starting someone my voltage gauge read much lower at idle(~12 volts but normally it's up just over 14). any increase in RPM would bring the gauge back up to it's "normal" mark over 14. i figured the alt was going(cheap chinese junk) and thought nothing of it other than "thank god for the lifetime warranty".

i went out the next morning and the batteries were so dead the truck wouldn't even attempt to turn over. Alternator was fine. :mad2:

 

[docdray]

two important things to remember out of this post:

1) just because top post tests good, the side post connection can be bad-or vice versa

2) even if voltage is correct, the battery can still be bad. just like a blown fuse can pass voltage but not amperage. load test is only true way to check.

an electrolyte test can help determine a bad cell

 

[JiFaire]

LOL... that's three things, Doc.

RayMich posted a thread like that recently... said something like "there are three kinds of people in the world; those who can count and those who can't"

j/k - great points about the battery issue - something that sooner or later, affects us all.

 

[Edzzed]

could maybe clean the top post terminals as the lead on the battery gets oxidized and that could cause a faulty reading. ever notice how shiny lead is if scraped clean. you could also sell the lead to a fisherman who makes their own downrigger balls. Ed

 

[docdray]

LOL... that's three things, Doc.

RayMich posted a thread like that recently... said something like "there are three kinds of people in the world; those who can count and those who can't"

j/k - great points about the battery issue - something that sooner or later, affects us all.

well, theres THREE things I will tell you, I mentioned two ways to tell if there is a bad battery, and second, the electrolyte test is just a gimmie if trying to salvage a battery- there!!!!:ciappa:

 

[JiFaire]

Yep, I been told by the Doc!