99 tahoe running high voltage

[Oley184]

hey guys i just got a 99 tahoe and when i first got it it was running at 16-17 volts and though that was kinda high to i went out and bought a brand new one and also a new interstate battery and now its running at 16-18 volts. and if i let it sit out to long in the minnesota weather she has one hell of a time trying to start 9 time out of 10 i have to be jumped... so if anybody could helpo me out that would be awesome!

 

[westman995]

How do you know that its charging that high? did you use a multi meter to get that number?

 

[autolover3]

Don't always trust the gauge unless you compare to a multi-meter. You say Minnesota weather huh? What kind of temps you having there, I'm from ND. In cold cold weather like we get higher charging voltage is normal. Normal charging voltage is abotu 14.4 volts and when temps drop cold batteries need a higher voltage to be charged compared to a 70 degree day. Mine is usually at 14-16 volts charging in the cold.

Also not starting, do you have a block heater and plug it in while it sits?

---------- Post added at 01:31 AM ---------- Previous post was at 01:30 AM ----------

Also make sure connections are good from alternator to battery that would prevent charging.

 

[kcb37]

You need to start checking for a drain.
Pull the negative battery cable, use a test light between the cable and the battery, start pulling fuses until the light goes out. That is the system draining the battery.

Like said it's not really the cold that causes a higher charging voltage. (does, not directly) It is the low charge of the battery caused by the cold that makes the voltage higher.

With a low battery or a dead battery the alt charges higher to get the battery charged and run everything.

 

[autolover3]

Damn you kcb37! I keep getting notifications and sure enough it's you

Just outa curiosity what is the pic of in your sig?? I just can't figure it out for some reason.