No start, multimeter showing battery at 14.X volts

M

Medic203

Member
Original poster
Joined
Jun 21, 2018
Messages
25
Location
Pittsburgh
2006 daily driver.

The last couple of days I've had some rough starts in the morning going to work no issue coming home though. Today was the coldest day we've had in a bit and I got the rapid clicking, but no start.

I figured it was from not driving much (I'm probably less than a mile away, and my gf usually drives everywhere in the evening).

Got a ride home from work and tried to jump it, didn't work.

I'm getting power inside, dash, lights, headlights, 4 ways, radio.

Put a multimeter in the battery and was getting a reading of 14?
My digital multimeter Is a cheaper harbor freight one, my analog only has 10 and 50 for dc.

Sounds like a low battery from the sticky. Rapid clicking, getting power, but it's not trying to start. But jumping it for about 10 minutes and it was doing the same thing.
 
Don't assume the battery is the problem; although it could be.
I would check the battery terminals, cable clamps, the starter positive connection and the ground connection at the block stud near the oil filter for corrosion and tightness.
Loose or dirty connections can create resistance that does not allow the power the transfer properly.
 
It does sound like the battery is toast, a bad battery can prevent the Jeep from starting even with some time charging. I'd guess your jumper cables aren't very heavy duty either but that's just a guess. Older battery, infrequent use and cold weather is death for lead acid. Not common for a HF meter to be off that much even at that price point. Can't you read the analog meter on the 50V scale? On a few of mine I just checked and 12-14 wouldn't be too bad to resolve. The things @CharlesHS suggested are a great place to start.
 
@pagrey the cables were pretty heavy duty, I'm a paramedic and we used the cables we use on the rigs. My analog did look to be around 12ish, but my understanding is the difference between full and dead is less than 1 (which I wouldn't be able to see well enough). I did have my gf come out and try to start it and it looked like it dropped to about 10 when she was trying to start.

@astjp2 I hadn't made it that far yet. When I got home it had already started snowing and the TJ is on the street. So I didn't make it past checking the battery after trying to jump it.

@CharlesHS I'll check them out! Though I just replaced all of my battery cables within the past 2 years.
 
14 volts indicates the engine/alternator were both running which gives a misleading voltage. 12.6v (AGM 12.8v) without the engine running indicates a fully charged battery.

My first step would be to physically remove both battery connections and wire brush them and the battery posts. Clicking indicates either a dead battery or a bad/dirty/corroded/loose battery connection. Even when they appear to be pristine.

One way to know the battery charge is to measure the voltage from the battery posts (not the connectors!) while the ignition switch is in the Start position. If it's 12v while the ignition is in the Start position and the starter is clicking odds are its nothing but a bad connection at the battery.
 
  • Like
Reactions: J.Pierce
Medic203 said:
My analog did look to be around 12ish, but my understanding is the difference between full and dead is less than 1 (which I wouldn't be able to see well enough).
Click to expand...

Medic203 said:
Put a multimeter in the battery and was getting a reading of 14?
Click to expand...
Anywhere between 12 and 13 is fine, you can't tell a bad battery by resting voltage but 14 means something is really odd and that was probably just the HF meter. Just wanted to make sure it was the meter giving the bad reading, I'd toss that sucker.
 
@Jerry Bransford it was showing 14 while the engine was not running, which is why I thought it was weird. But someone else suffering it might have just been the cheap multimeter I was using. In any case I'll hit them with a wire brush and see if that helps.

@pagrey yeah I wasn't sure if it was a wonky reading, or if I failed to do a calibration or something. Outside of jamming it into an outlet I'm not really sure how to check.
 
  • Like
Reactions: Jerry Bransford
A quick battery check I have found useful is with engine off, turn on high beams and measure voltage at the battery. A battery will often appear to be fully charged with no load but as soon as you put any sort of load on it, it drops below 11 volts or so.

Same idea as suggested in post #3 but easier to do.
 
  • Like
Reactions: J.Pierce
@Noslo65 I have AAA, so was considering calling them to test the battery. Otherwise I'm not sure how to test it myself outside if what I already did (saw a drop in v when my gf tried to start it).

@g.hayduke I actually replaced my headlights with LEDs, so didn't think the headlight thing would work. My 4 ways are still incandescent, but are bright.

@LONGJP2 I'm fairly certain the battery isn't more then a couple of years old. I can't actually remember if I replaced it last year or not (I was having starter issues from a corroded wire).
 
Top Bottom