8.5v when started... Need Batteries?

[chrispaine]

Well I left the radio on the other day with the truck off, for about an hour. With good batteries I'm sure it would have started so it was a good indicator that they are due to be replaced. I jumped the truck and drove it home (half hour drive) the next morning it was very slow to start and almost didn't start at all!
Put my fluke on it and it recorded a min of 8.5 (that's with the meter recording the min so the 8.5 is the very lowest the voltage dropped to) volts when started, and it was reading 14 volts when running. I am assuming it is just time for some new batteries but I just wanted to check with you guys and see what you think. At 14v is my alternator putting out normal voltage?

-Sorry, kind of a stupid question but with batteries being so damn expensive these days I just wanted to make sure that I need them!

[NoRalPh]

Even a 1/2hr drive isn't bringing them back to anywhere near to full charge.

For a "fair" test, you should get them on a Big charger and bring them back to Full Charge. Then monitor the starting voltage (keep in mind this is only a 1/2-assed test anyway, to really know you need to have them individually Load Tested after a full charge)

[chrispaine]

Originally Posted by NoRalPh

Even a 1/2hr drive isn't bringing them back to anywhere near to full charge.

For a "fair" test, you should get them on a Big charger and bring them back to Full Charge. Then monitor the starting voltage (keep in mind this is only a 1/2-assed test anyway, to really know you need to have them individually Load Tested after a full charge)

Thanks, I have a charger on the truck now but they are not disconnected from the truck so I am assuming it should charge them both. I will bring them into the parts store tomorrow. But they do have 07 date codes on them, came in the truck so I'm out of the warranty!

[NoRalPh]

Yea, they're Both getting charged at the same time.

5yrs/old is getting there (I got 8 ) but it's the winter starting that makes good batteries necessary. So, it they test border-line now I'd replace them....

They might well be good still though!

[chrispaine]

I will see what they go down to when cranking after a good charge, I have a 10amp charge on them now so will will see later tonight or in the morning.
And yeah the Michigan winter will kill them for sure so I will end up replacing them before then but i would like to get a few more weeks out of them, spent too much on the truck lately!

thanks man.