ive been having a problem with my xj voltage gauge randomly going up to 19 volts then back down to 14 and not sure whats going on. alternator going bad? bad grounds somewhere? anyway ive wanted to upgrade my battery cables anyway because if youve looked at them before you would see how small they are. what do you guys run? ive seen the jeepers creepers ones and the 5-90 ones (http://www.kelleyswip.com/) what would you guys suggest? thanks

 

Before you suspect your cables (they're only 12 years old, if you're referring to the 2K in your profile...) there's a couple of things you should do:

0) Verify suspect IP readings with a direct reading, using a DMM. The earlier IP gages are worse, but the IP gages, in general, are notorious liars - and don't usually take a direct reading of system voltage.

1) Check your grounds. Clean/replace hardware/reterminate cables as indicated.

2) Check your battery terminals - corrosion under the clamps can cause all sorts of headaches.

3) Check your alternator mounting, make sure it's tight and clean. Oil there can contaminate the connection and screw with system voltage, and the alternator is grounded through its mounting.

Why is the separate check numbered zero? Because it should always come first. Period. Full stop. Any suspect reading at the IP should be verified independently before any other troubleshooting is undertaken.

ALWAYS.

 

Another problem that could explain overcharging is a short in the battery. Have the battery tested. If it tests ok, then go with what 5-90 suggested.