Battery Draining

[jneary]

its usually 20- 25 milliamps. make sure the glove box light , rear cargo lamp or sun visor lamps arent staying on

 

[tgregg]

Yea! Actually I need to figure out how to make the AMPS thing on my volt meter work. I've tried it and it jumps to -1. It seems to start to give a reading and then makes that jump. But at rest AMPS draw would be good to know. I'm about to just put a switch into the circuit to shut off the battery when it is sitting. But if the problem draw is progressive then that won't help! The XJ used to sit for weeks and start right up now it has a TOTALLY DEAD battery in 4 or 5 days. Same radio, same everything!

 

[Shorty]

mili-amps is a more likely measurement for "at rest" parasitic draw. Around 6-10 mili-amps is stuck in my head for some reason.....

 

[winterbeater]

Found some old history for current draw.

Geekstarrs test is a good one, although I like to use a multimeter set on milliamp scale, instead of a test light. Then pull fuses until you find the right circuit with the draw.

I think you'll find a constant 6 mA draw, that is constant no matter what you disconnect (although 30 mA is indeed excessive). It's caused from the ECU being powered with the key off. It's not enough to be concerned with, unless the XJ sits for an extended period.

If you have a courtesy light above the passenger side visor, make sure it's actually turning off. Also underhood light, if you have one.....a 30 mA draw is about right for a small bulb being on somewhere.....

Basically, with the meter, start out at the highest range in amps. If it reads negative, switch the leads. If you get a small reading on the meter. Kick it up to the next range. This is kind of directions for an analogue with a needle. Doesn't your (assuming digital) have an autorange feature?

 

[tgregg]

No Auto Range that I see maybe I need to buy a new volt meter. This one is digital but I've had it 25 years or so!
Anyway in the morning I'll get out and play with it some more. I really appreciate the help.

 

[wim hoppenbrouwers]

Hallo. If you do a test with a light (Advisable is using a led.), take care every user is off.
Light in the engine bay and interior lights.
You can take out the fuses one by one to see where the drain is coming from.
When you use a DMM. Use the 200 mA or 300 mA . A normal drain will be about 30 mA. If the drain is very high ,like a short, the DMM fuse will die.
The current is DC! :roflmao:

 

[tgregg]

Thanks, The drain is pretty low. It takes a week to get too low to start. I have recently added the CB and I'm wondering if it has a draw when off. My XM power cord is also plugged in and those combined with the regular radio draw maybe that is the biggest part of the problem. On my BMW motorcycle I just leave a trickle charger on it when I'm not riding, maybe the XJ needs the same now that I don't often drive it.

 

[winterbeater]

A CB turned off shouldn't draw anything (no memory does it), but you can check it with your meter. When my battery is on it's last legs, I have to start it every couple of days. But for the first 2 years or more after it's new, it's good for at least 3 weeks.

 

[muduck18]

A CB turned off shouldn't draw anything (no memory does it), but you can check it with your meter. When my battery is on it's last legs, I have to start it every couple of days. But for the first 2 years or more after it's new, it's good for at least 3 weeks.

it shouldn't, unless they put one of those "line Cleaners" in that "cleans the power" to the cb. They have a very small, but draining power that's always on.

 

[tgregg]

My XJ seems to be drawing 5.5 amps at "off". I'm thinking that is about right. My motorhome start battery used to do the same thing, that is kill the battery after a couple of weeks. I put a little trickle charger on it so I didn't have to start it weekly and that solved the problem. Same with my motorcycle. I'm thinking I'll do the same with the XJ. Thanks everybody, I really learned a lot through this discussion.

 

[dogsled1]

5.5 amps off is way too high, should be in the milliamp range as stated earlier. Some meters display the -1 when they are out of range, usually indicating too much of whatever you are measuring.

You can also disconnect one of the cable to make sure that the drain is not internal to the battery with a bad cell, although that should show up if you get the autoparts store to test it.

 

[joe_peters]

5.5 amps off is way too high, should be in the milliamp range as stated earlier. Some meters display the -1 when they are out of range, usually indicating too much of whatever you are measuring.

You can also disconnect one of the cable to make sure that the drain is not internal to the battery with a bad cell, although that should show up if you get the autoparts store to test it.

x2, you are a stranded motorist waiting to happen.

 

[lawsoncl]

5.5 amps sounds like the interior lights are on. You did shut the car door when checking right?

 

[Jeepm@n]

5.5 amps is way too high. My 94 with aftermarket CD sits for a minimum 3 weeks at a time. Never had to jump start it. You have a draw that is not normal. Give us your power options on the vehicle. Check the rear dome light switch it has been known to cause issues. The trickle charger is just a band aid for the inevitable. I do have a solar charger but I do forget to hook it up 99% of the time. P.S. I checked my amperage draw and it is 4.9 milliamps DC.
Not 5.5 amps.

 

[tgregg]

Yes I agree, something has changed. I've checked all the lights, I've unplugged everything. It was fine until my last Death Valley trip and since then the battery is pulling down. The dome lights are not lit but I'll take a look at the switch. Perhaps I need to take the rear one apart and look for a short. I suspect though it is internal in the alternator. I went out with my local Jeep group Saturday. With the air running, cooling fan running full time, CB on, GPS running, XM and dash radio on, my volts showed 11 to 12 volts. I know that is a big draw but shouldn't the alternator be showing 14 when underway still?

 

[winterbeater]

Seems like the alternator may not be up to the task. When you turn all that stuff off, does it go back up to 14V?

 

[tgregg]

Yep!