Why did I have to charge the battery?

[Black Bob]

05 Liberty Sport with fairly new battery. Noticed slow cranking over a few weeks. Decided to charge the battery. Charger showed only 50% battery charge. Appears alternator may not be putting out but idiot light not glowing. Battery charged up fine. Any ideas anyone?

 

[tjkj2002]

05 Liberty Sport with fairly new battery. Noticed slow cranking over a few weeks. Decided to charge the battery. Charger showed only 50% battery charge. Appears alternator may not be putting out but idiot light not glowing. Battery charged up fine. Any ideas anyone?

Stock spec battery you may have a issue but if it has more CCA's then stock the stock system will not fully charge it and it will require a actual charger to fully charge it every few months.

 

[Billwill]

What charging voltage are you getting over the battery when running?
Should be about 13.4 volts.

Make sure all the battery and all large engine grounding straps are clean and tight.

You may have a current drain on the battery when standing switched off overnight.
You need to put a meter...set on AMPS....in series with the battery.

Do not start the engine or you will blow a fuse inside the meter.

Current drawn should be not much higher that about 30 milli Amps ie. 0.030 Amps.

If it is much higher you need to pull fuses out one by one to see which circuit is causing the drain.

 

[LibertyTC]

What battery do you have & what CCA is it listing? Use a Voltage ohm meter and with Jeep running tells us what the volts reading is.
You need good amps & voltage output to keep the battery charged up & have it run for 30+ minutes per day.
After sitting overnight a good reading should be over 12.4 volts unless there is a drain somewhere or a weak battery. This is where a load test is also a good idea.
My ALT shows around 14.5v fired up first thing in the AM no real draw- No lights, or blower motor on etc.
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When below freezing you have less cranking power- This chart explains much.
Having an 800CCA + AGM battery is a real advantage come winter time.
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[Black Bob]

Man, thats a lot of technical stuff. I'll see if I can figure this out. My brain is old and I'm not too electrically inclined.
It's an Exide group 34 saying CCA at 0 deg.F 630 CA at 32 deg F 785. I have a cheap meter but don't know how to use it much. Mostly test AAA batteries and what not. It's a Harbor Freight Cen-Tech. Should the car be running? How do I hook up the leads? Thank you all for the help.

 

[Black Bob]

Looks like I'm getting 14.7 if I did everything correctly and had the car running. BTW, the KJ sit a lot and only has 72K on the clock. Really not sure how old the battery is. Thought it was only a couple years old but could be wrong about that. Thanks for the good will.

 

[LibertyTC]

14.7 is good output voltage so it's charging probably ok.
Lead acid batteries tend to last 3-5 years, and trickle charging them especially if a vehicle sits is always good to keep them topped up.
I would recommend charging the battery overnight @ 3-6 amp setting & then take it into a shop for a battery load test, that will confirm the available CCA = pass or fail.
Many do not charge for a load test.
Automatic intelligent chargers are handy & I use the C-Tek which does a great job for keeping my battery up to speed.
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Which battery charger are you using?

 

[Black Bob]

Walmart, Schumacher I believe.

 

[JasonJ]

Walmart, Schumacher I believe.

Schumacher is decent stuff, I've never had an issue using them before. As long as it is set correctly to your battery type (deep cycle or not, amp settings, et al) you should be fine with that.

 

[turblediesel]

Might be a "letter-number" dot stuck to your battery, top or sides. Letter is month manufactured, number is year. Same code might be melted into the side lip of the plastic top of the battery.

 

[Black Bob]

I'll be checking for the date codes. Usually I keep the receipts but I can't find this one. Thanks to all that contributed. All very useful information for me. Thank you.

 

[Black Bob]

Bought a Harbor Frt. load tester yesterday and it appears the battery is weak. Then, as suggested by TD, the date was April 2014, plus over 2 or three days, after i charged it up, it fell to 66 Percent. Guess I'll be getting another one soon. Thank you all for the help.

 

[JasonJ]

Bought a Harbor Frt. load tester yesterday and it appears the battery is weak. Then, as suggested by TD, the date was April 2014, plus over 2 or three days, after i charged it up, it fell to 66 Percent. Guess I'll be getting another one soon. Thank you all for the help.

Telltale signs of a weak/bad battery.

Check the new battery when you get it as well... if they sit on the shelf waiting to be sold, they can lose 0.10v per month.. sits for 4 or 5 months or more and it'll be a dead battery (not bad, just dead) right from the get go.. and will need to be recharged before being put into service.

 

[LibertyTC]

Bought a Harbor Frt. load tester yesterday and it appears the battery is weak. Then, as suggested by TD, the date was April 2014, plus over 2 or three days, after i charged it up, it fell to 66 Percent. Guess I'll be getting another one soon. Thank you all for the help.

Consider getting an AGM battery. (absorb glass mat)
As sealed type, you will never have to worry again with corroded terminals.
AGM's tend to be very powerful around 800CCA and are considered a deep cycle battery.
The best is an Odyssey & tested at 1219 CCA when new.
They last a very very long time indeed. Virgin lead and never a catastrophic failure.
ODYSSEY Battery - Design Advantages

Other AGM's like Excide Edge -(Bosch) and Deka almost all manufactures are offering AGM batteries today.
My Odyssey is now 8 years old and still performs great, well worth the $.
The other AGM are under $200 and should well last 5-6 years.