Topic: Help Please (Read 3860 times)

Panic mechanic! · « **on:** January 08, 2012, 01:30:53 PM »

Anyone out there can do me a favour who owns a 4.0 wj, I need someone to measure the voltage at the battery an off the alternator when its running an let me know asap!

Dave The Sparky · « **Reply #1 on:** January 08, 2012, 04:54:00 PM »

They should both be the same voltage seeing as they should be connected together, if there is a difference something is v.wrong!

charging volts should roughly be between 13V and 14V on any 12V car.

Panic mechanic! · « **Reply #2 on:** January 08, 2012, 05:23:39 PM »

mmm I am having a head scratcher on this, on christmas day went to the wj, flat as a pancake,checked the battery and jumped it thinking I must have left something on and it went dead again quite quickly.
same happened again yesterday after Jay gave me his old battery to fit on boxing day, alls been fine since then. then yesterday gone again, jumped started it and got my multi metre out checked voltages...15.3 volts coming out , so took it for a 20 min drive , turned off and checked across the battery voltage steadily dropping down..... this morning went out expecting flat battery and it started fine! lol

Dave69 · « **Reply #3 on:** January 08, 2012, 09:34:04 PM »

Have you measured the system drain on the battery to ground as you could have a short somewhere (interior light door sensor etc).

Panic mechanic! · « **Reply #4 on:** January 08, 2012, 09:37:00 PM »

yup thats one of the reasons I am head scratching.

jay140285 · « **Reply #5 on:** January 09, 2012, 01:18:33 PM »

There isn't a lot inside Robs head, so he could be scratching for sometime.

scrw · « **Reply #6 on:** January 09, 2012, 07:22:04 PM »

multimeter between battery & +ve with everything turned off & see what drain (if any start pulling fuses until it stops to find the source)

Panic mechanic! · « **Reply #7 on:** January 09, 2012, 10:26:07 PM »

have tried that already,think its just winding me up .lol

scrw · « **Reply #8 on:** January 10, 2012, 06:52:17 AM »

wonder if its the hvac doors stalling now and then & draining the battery, have you run the hvac diag to see if there are faults

Delk · « **Reply #9 on:** January 10, 2012, 06:59:20 AM »

15.3 sounds to high, the voltage is controlled by the ECU and is normally kept pretty steady in the mid 13's

Panic mechanic! · « **Reply #10 on:** January 10, 2012, 07:24:03 AM »

a little bit of an update the battery seems to be holding charge again, yes I thought charging at over 15v is high but then again this morning when it was running it was at 15.8v, I have had a battery guy tell me that some battery's when they are getting tired on the last legs will charge at that rate before they eventually die an yes the alternator can wack it out at that rate as well!

Bubba · « **Reply #11 on:** January 10, 2012, 12:50:25 PM »

you need to buy or borrow a known good batt at the moment you may not get good test results

gazjeep · « **Reply #12 on:** January 10, 2012, 01:11:12 PM »

Got the original off the TJ that I keep topped up in the garage & use with Tmax compressor if you want to borrow to compare Rob.

I dont know if it will fit but your welcome to try it

Panic mechanic! · « **Reply #13 on:** January 10, 2012, 03:42:12 PM »

cheers Gaz, I may take you up on that,having a known good battery my help a lot,as kev says.

gazjeep · « **Reply #14 on:** January 10, 2012, 06:35:23 PM »

No probs

gazjeep · « **Reply #15 on:** January 15, 2012, 10:38:14 AM »

Any joy with the battery Rob ?

Panic mechanic! · « **Reply #16 on:** January 15, 2012, 11:55:31 AM »

yes and no, looking more at it this afternoon

jay140285 · « **Reply #17 on:** January 15, 2012, 08:24:56 PM »

How have you got on after I say you mate?

Panic mechanic! · « **Reply #18 on:** January 15, 2012, 08:28:44 PM »

didn't get chance to do anything else but I will try tomorrow, just got to do some work on the cj ready for it vanishing this weekend.

jay140285 · « **Reply #19 on:** January 15, 2012, 08:30:40 PM »

You want a hand the weekend to move it mate?

Author Topic: Help Please (Read 3860 times)

Panic mechanic!

Panic mechanic!

Panic mechanic!

jay140285

scrw

Panic mechanic!

scrw

Delk

Panic mechanic!

Panic mechanic!

Panic mechanic!

jay140285

Panic mechanic!

jay140285