UMMMM No voltage

[JARichard]

Was Xmas shopping and the check gauges light came on. I had 0 voltage displayed. I knew this had to be wrong because all lights and electronics were working fine ( or I thought) . An hour later the light go dim and things started shutting off!

Well, I got to the garage and checked the voltage one battery measured 12. 56 volts the other 9. 3. Put the battery charger on the weak battery.





Then i said Hey Dummy turn the truck to ON and see what the voltage registers.

Still 0! ( It probably was a dumb move but I was not thinking properly)

Both eyes of the batteries are green and I am surprised I had that much voltage in them with the lights going dim and the ABS shutting off!



I let the battery charge for a while started the truck and the volt meter has worked ever since!!!



So, what do you think the problem is or where should I start troubleshooting????

 

[tkerrigan]

Get two new batteries, the 9. 8 volt battery has an internal short, the other battery is ok, but you want matched batteries.

 

[LesStallings]

Fully charged batteries are over 14 Volts. So much for the 12V battery myth!

 

[nps]

Get two new batteries, the 9. 8 volt battery has an internal short, the other battery is ok, but you want matched batteries.

Agreed on the 9. 8V battery. But why do you want matched batteries? I've been running an Optima Yellow Top along side one of my factory batteries with no ill affects.

 

[JARichard]

The batteries were low but I don't think the alternator was charginf because the volt meter was showing 0. before i could get home the lights were very damn dim. Plus, I was checking the batteries while they were still hooked up. To me they would have read the same. Is there something that just draws off of the passenger side battery and NOT BOTH?

 

[JFaughn]

Thats why thinking about the batteries and alt as seperate and test them both on a regular maintance scedual , the batteries can kill the alt and the alt can kill the batteries, with frequint chech ups you can find one before the other goes. a fully charged battery is 12. 75v , the higher voltage is charging current , and definatly replace batteries as pair , a 12v battery is made up of 6 cells and if one is bad then the battery is bad , same thing with a battery bank of batteries the bank is as good as the weakest cell or battery [ the bad limits how good the bank can get]

 

[K5IP]

If the two batteries were still hooked together they had to read the same. (They are in parallel) You either made an error in reading them, or there is a bad connection in the cable between them. There is nothing that can discharge one battery only.

If, indeed, you did measure different battery voltages while connected, you probably do have a bad connection between batteries. Look for corroded battery terminals. This could also explain the zero voltage reading on the dash since power take off points are distributed between the batteries. In addition, this also resolve the low voltage condition on one battery since it may have been isolated from the charging circuit. In fact, if you charged it with a battery charger and it is holding it's charge, as witnessed by a good voltmeter reading, the battery is probably also ok.

Rog

 

[MLimpert]

Check for trouble codes as well. My truck stored one when it did almost the same thing. That was 6 mos ago and it has not come back. I believe the volt meter works along the same lines as our oil pressure gauges, and it is just a computer generated idiot light.