Drop in voltage

For the last few weeks I have been having problems with my voltage, so today I installed a new Optima yellow top and a few weeks ago a new alternator. Instead of having 13-14volts im still at 10. So Im thinking that it is a grounding problem. What are the most common issues for this problem?
I have an 89 XJ.

-Frankie

are you baseing this on the in dash voltmeter or by using a handheld voltmeter directly on the battery terminals?
The factory in dash voltmeter sometimes lies on older vehicles.My in dash voltmeter on my 89 tells lies.Use a voltmeter on the battery terminals with the engine off it should read around 12.5 v and with engine running it should read around 13.7 or as high as 14v

Im baseing this off of my dash. Ill check it with a voltage meter as soon as I re-aquire one

xjfrankie said:

Im baseing this off of my dash. Ill check it with a voltage meter as soon as I re-aquire one

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Good idea - as mentioned, the IP voltmeter is a notorious liar.

However, primary grounds to check are the engine-firewall ground strap, the battery-engine ground, and the battery-chassis ground (1991-later.)

Also check that the alternator mounting is secure and clean (it grounds through the case,) and that you don't have a buildup of crud in the firewall ground strap (especially for 1990 & earlier.)

xjfrankie said:

Im baseing this off of my dash. Ill check it with a voltage meter as soon as I re-aquire one

Click to expand...

What looks like 10 volts (labeling on the meter, or lack thereof) is actually about 12 to 12.5 volts. Check the needle position with the engine off, power on, that position is the battery voltage which is about 12.6 ot 12.7 volts. If the running volatge is there or higher you are OK.

xjfrankie said:

Im baseing this off of my dash.

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The volt gauge is useless except for relative change, I've seen a few that read realtively accurate (with no electrical load) but most read low.