93 Cherokee charging system?

[WagoneerXJ]

I've got a 93 Cherokee 4.0 5spd. It charges intermittently. Usually charges in the morning when the engine is cold (according to the gauge on the dash) and after a while the gauge drops and stops charging. Have to charge the battery for a while at the end of the day.

 I put in a brand new Alternator, with no change. I was told the charging system is regulated by the computer, so I have a spare computer and swapped it in. Same year, same engine, but for an auto, it seems a little better, but it still quits charging eventually.

So I'm wondering what else I can do. Any ideas?

[jkrubi]

You cleaned all the wires to and from the altenator and battery? Checked your grounds? Battery posts and terminals? All cleaned.
As well you have no broken or burned or damaged wires?

Have you checked the output of the altenator yet? If still on the jeep the easy way is to start it and turn in all the high draw equipment that you can, ie rear defrost, high beams, heater fan on high, factory fog lights. Don't use aftermarket stuff, just oem jeep electrical, and see what the altenator is putting out at the battery. If its 13-14 volts ten its charging, if it's 12.? Usually it's not but it should be over the rest voltage of the battery.

As well before starting the test, fully charge the battery, and see what the voltage is sitting at rest. The alt will always be over that, if less then you will have problems.

If the alt is pulled out already take it down to auto value, I think the do free testing of the alt on a bench.

[jandh]

Throw a meter on your ground and monitor it vs your charge rate, see if there is any change around the same time your charge stops.  Also what kind of battery do you have? anything fancy with your electronics?  you could also try another battery if you have one around may not be an alternator problem, I have had similar issues with a brand new battery that a bolt head in the battery pan scratched its way through the plastic and drain some cells.