Battery 101

[Coaster_DC]

Wednesday, after making multiple trips, Jeep ('97 xj) decides not to start. Battery is dead. Got jump from stranger, but had to move jumper clamps around terminal to finally make contact. Vehicle starts up. Thursday in parking lot, again after multiple trips around the city, Jeep battery is dead, no headlights, no juice, nothing. Got jump again, this time with more difficulty trying get a "contact" on my battery. Road service suggested maybe bad terminal clamps. Plan on replacing battery on Friday (only had the vehicle for 2 months, so don't know how old the battery is). Question: can a battery discharge within a 3 minute period (time enough to go into a convienent store) to where it is completely dead, not any juice at all, where not even headlights will come on. Could this be more than just a bad battery problem. Last 2 nights were colder than normal...low 30's.

[nickyg]

If I had to guess I'd say check your battery cables for corrision, (dark or greenish copper) A funky cable can do weird stuff.
Your in luck, Josh just went over replacing / upgrading the battery cables in the podcast. episode 72 I think.

[Metlic53]

I would say your terminals are real dirty and aren't getting a good enough connection even if they look clean. Mine do this sometimes, battery seems dead but i can get a jump pretty easy, does it again so i'm thinkin bad battery, my dad comes out, wire brushes the terminals, clamps them down nice and secure, it starts right up...that was my situation, hopefully this is all you are dealing with too.

[Mudderoy]

Wednesday, after making multiple trips, Jeep ('97 xj) decides not to start. Battery is dead. Got jump from stranger, but had to move jumper clamps around terminal to finally make contact. Vehicle starts up. Thursday in parking lot, again after multiple trips around the city, Jeep battery is dead, no headlights, no juice, nothing. Got jump again, this time with more difficulty trying get a "contact" on my battery. Road service suggested maybe bad terminal clamps. Plan on replacing battery on Friday (only had the vehicle for 2 months, so don't know how old the battery is). Question: can a battery discharge within a 3 minute period (time enough to go into a convienent store) to where it is completely dead, not any juice at all, where not even headlights will come on. Could this be more than just a bad battery problem. Last 2 nights were colder than normal...low 30's.

Yep, I bet it's the cable connections to the terminals. You'd be surprised at just how important good contact is. The battery doesn't get charged and this thin film of stuff forms an insulator between the post and the cable.

It could be a bad cable(s) too, but most of the time I've had this problem it was the cable/post connection.

I have several of these...

1732

Just pull the battery cable off the post then run the brush on the inside of the battery clamp until it's shinny, then use the other side to do the same thing to the post. They are lead so don't do it too much. Soft metal. Also there is probably battery acid on those surfaces, so wear protective eye wear, and a old shirt. ;)

Also if it does it to you again, you know before you clean the terminals/cables, try hitting the cable ends, just tap them both. If you have a door open or leave the overhead light on you'll see it get brighter as the cable makes better contact. If taping them makes them move, pivot on the battery lug(s) then the cable clamps are too loose. Clean and tighten.

[prerunner1982]

I had a similar issue and it was the battery. Would hold a charge for a couple days and then one day after stopping somewhere it wouldn't have enough to restart. Would fight with it dying for a day or two and then it would be find for awhile. My battery was old and I think it had a cell that would not always hold a charge.

Also, who says it lost it's charge in the 3 min you were inside? While the Jeep is running the vehicle is running off the alternator, so it could have been discharging since the last time you started it while you were driving it around.

I agree clean the cables first just to see but if you are going to replace the battery anyway hopefully that will fix your issues.

[NW99XJ]

Yup, Just like Tony (Mudderoy)says....clean things up nice and shiny.
The Cherokee's are EXTREMELY finicky when it comes to voltage.
I had this EXACT same thing happen to me once before.
Almost left me stranded.
In my case, not only were the terminals corroded....but the wires IN the terminals were so oxidized, that there was very little electron flow passing thru them.
I ended up having to replace the terminals, and cut the wire back a few inches to remove all the cancer.
The stock XJ battery terminals are molded to the wires. You cant just take them off....you have to CUT them off....no biggie.....there's just enough extra wire to work with to affix to new terminals.
I would recommend replacing them anyways. Better continuity is always a good thing!
Dont cheap out here.....go with some good mil-spec or solid brass marine grade battery terminals....they will last longer, resist corrosion more, and give you easier access to for wiring upgrades later in the future.
If you have some extra cash and want to tackle the job....I would highly recommend upgrading the charging system's wiring and vehicle grounds. (not as hard as it sounds)
This would entail replacing all the ground wires, and the wires going from the alternator to the battery, and from the battery to the PDC (power distribution center)....the stock stuff is puny, and upgrading to 4 gauge or 2 gauge wire is a huge improvement.

I have covered tips and tricks, and outlined certain things to pay attention to in recent podcast episodes, as well as did a decent pic-heavy write-up on this in my build thread.
I hope some of this helps.
Good luck!

[denverd1]

bad connex bro

[dagod16]

First off. Go into autozone and have the battery load tested. If they say its good then its the connectors. I see this with my high school kids all the time. 7 8 or 9 year okd battery and they need a jump. I never have battery issues. If a battery is designed to last 7 years I replace it at 6. My jeep needs to start and a battery is 100 bucks about 14 dollars a year. Just buy a new one. After u install it , in permanet marker write on the battery the year it expires