Okay, so I purchased a 1990 Cherokee a month or so ago, and have had a myriad of issues to go along with it, I've gotten some help from the kind folks here and I am in need again!

My current appears to be a battery drain, or so I thought. Brand new battery, brand new alternator, and the battery still dies on me. It dies if I havent driven it for a few days.

I have a multimeter that I used to test for a parasitic draw with the key off and it came up normal. Between 30-50 milliamps. (if I am usining it 100% correctly, I have honestly never used one before).

I am at a loss here. Outside of disconnecting the battery when I am done dribving it for the day to make sure it holds a charge, I have no idea what to do.

The guy i bought it off of, installed some aftermarket stuff, so I thought that could be it, but with it not reading a parasitic drain I have no clue.

 

Working off the negative post, less chance of short something if using the hot side, Pull fuses one at a time of suspected aftermarket installed items. A drop in ma should be seen if the problem is in that system. Then you can see what that fuse protects and unplug those items one at a time to check for ma drop. Also relays can be stuck open so you can do the pull method with those as well. I am no electrical guru but this has worked for me in the past. Yup very time consuming, so start with alarms and radios or auxiliary light if added. I know you said alternator was new but google around for a test for that because if a diode is bad it can draw as well.

 

30ma is fine...even 50ma should last + 2 weeks

how quick does it drain ?

a test light is easier if you are not multimeter familiar, connect between + terminal and battery + post..test light should not light

if it does, pull fuses first, report back

dont allow your battery to be repeatedly drain to dead flat...that is a killer for lead acid batteries...completely flat is one charge cycle..a lead acid battery can have as little as 30 cycles lifespan
A normal start might only use 0.0001 of a cycle, and the fully charged by alt, so last a few years, if not allowed to run flat

 

Amen, and amen, and amen.

A BatteryMinder is a wonderful thing.

 

30-50mA sounds high to me. But it should not kill your battery overnight. My zj draws about 14mA for the security system to run which is book normal.
If I were you I'd start by bringing it to a couple places to have the system checked = in vehicle. Autozone, napa... More than one because they don't all do such a good job of checking.
Specifically you want them to check for open or shorted alternator diodes. There are 3 of them and you need all 3.
Your battery fully charged should be 12.6 volts. 90% discharged is 12.0 volts. When running it should hold around 13.8 to 14 volts with all the lights and heater on. (which I disagree with, it's an example of Chrysler's terrible voltage regulator in the pcm, which is why I went to external regulator. )
I have seen on here where guys will check for parasitic draw across each fuse with a voltmeter to look for voltage drop across the fuse. Anything other than 0 volts means you have current flowing.

 

1993 XJ. Getting an automotive multimeter is key. I was initially trying with an electrician meter, but it just didn’t see the draw.

got the meter inline on the ground/negative side and immediately saw a 9 amp draw. Then nothing! 10 seconds later, 9 amps for a couple of seconds, then zeros! The cycle continued. Now what? Pulling fuses was going to take forever.

fortunately I was all alone in the shop and it was very quiet. I noticed a faint click when the draw went up and again when it dropped. Somewhere in the cabin. Something that works when the ignition is off? Power seat! Unplugged the connector under the seat and flat zeros! Switch? Motor? Don’t matter, I’m back in bizness.

there is a fuse as well (#16), but I’ve left the connector unplugged. Maybe have another look when it is back inside for its next oil change. (590,000 km’s!).

now to find out why the daytime running lights suddenly decided to not turn off when the xj is shut down.