Well me and sum friend went muddin today and on the way back my battery gauge dropped to 0 and check guages light came on..but starts up just fine and will sit at around 12 then drop down to 0 what could cause this???


*UPDATE* Alright well today I had to jump it and took it to o'reillys and they tested a bad battery so I was headed to where I work so I could get a discount and it started missing VERY VERY VERY BAD..and then died so we jumped it again and it didnt even wanna run but i managed to get it to a parking lot then we put a new battery in it 650CCA and 800CA-NEW
OLD-630CCA 730CA and still only stays at 12volts then drops to 0 so I guess its just running off the battery charge since the ALT isnt charging it my friend said try and spray carb or electric cleaner into the Alt to try and get sum mud and stuff out of it..a New alt is around 200 everywhere iv checked*UPDATE*

 

You've probably gotten mud in your alternator - the XJ mounts it low, and everything splashes up in there. Try blasting it out with some electrical contact cleaner, then lightly tap it with a wooden mallet or a wooden block.

What commonly happens is that grit manages to get into the brush holders at the back of the unit, and they get stuck away from the sliprings. You're flushing the grit out, and the tap should reseat the brushes against the slipring. The brushes are near the centre, at the back of the case.

Don't get too silly with the solvent, unless you're going to remove the alternator and open it up. The rear bearing is often an open roller setup, and you can flush the grease out of it and need to relubricate that bearing (white lithium grease usually works fairly well there.)

 

update

 

did you fry the alt? try thoroughly cleaning out the engine bay and see if that helps any. i think normally the volt meter should read at like 13.6 or 7.

 

IDK usually my battery gauge is at 14 and not it wont rise above 12 just fall way below

 

I dont know if it could even be related, But Mine used to start off around 12 and drop down below 8 by the end of the trip, Come to find out, it was the actual guage, Put an aftermarket and it stays 14+ the whole time

 

idt it would be the gauge cause its missing and causing the battery to lose voltage