Topic: Slow cranking after car sits

[Hipo giddyup]

 Just as the title states. After a few days, when I start the car it is super slow as if the battery is drained. After it starts and runs for a while  I can shut if off and it starts normal. The battery is brand new (my old battery was 7 years old and I assumed that was the slow cranking issue, never assume).
  I have already checked for a drain on the system, using my multi meter set to 10A, connecting to the black lead to the Neg battery post and Pos lead to the Neg cable - off of the post-, I get nothing - doesn't register. This is not showing a drain from what I am reading on this?  I then checked the alternator by taking the wires off of the alternator and testing the diode. I get 940mv (positive lead on case and black lead on Alt. Pos post) but nothing shows with leads in reverse, which is supposed to show the diode is working correctly. I checked the charging of the battery and its great, around 14.4v at idle. When I have the lights on, radio on, and heater working, it drops and maintains 13.6- 13.7v . I guess I can start pulling fuses anyway and let each change sit for a while until I see which has no effect on the car starting (that should be the bad circuit), but reaching out to see how to test if the starter is going bad or starter relay? Any ideas

Maybe Midlife will see this. LOL

Sorry I am not good with electronics..

[dave6768]

You have to also change one of the plug on the MM to the amp location.  With the meter connected turn on something like an interior light and confirm you are seeing an amp draw.

What it the voltage on the battery when it sits for a while?
Have you tried charging the battery and then starting it?

Sounds like you may have a parasitic drain.

[preaction]

Is the oil the correct multi weight for your application ?

[midlife]

Change your setting on your multimeter to 1 amp or lesser setting than 10 amps.  You should see something: typically 10 milliamps due to connections. 

Alternatively, it could be due to a battery that's going bad.  Take it to Autozone for a load test.

[tobkob]

Since it sits for several days why not just disconnect the positive cable and see if starts normally the next time (after reconnecting cable  )
This will tell if there is a parasitic drain or a bad battery, then if it starts normally then you can start searching.

TOB

[Hipo giddyup]

Thanks for all the input. I am taking the battery in to be tested. First time I've purchased a Napa battery, I hear they are good. I bought this one to retain the battery topper.

Once I get the battery straightened out, I'll see if that was the issue, or start diagnosing then. Its good to learn troubleshooting this, and I appreciate all the help!

[Hipo giddyup]

I had some time to play with this issue. Haven't had a chance to take the battery to test, but charged it and so far it holds a charge( unhooked and left alone for 4 hours - maintained 12.56 volts).
I tried my multimeter on 200ma but it still showed 0.00 when using the positive probe on the neg cable , neg probe on the neg post. I watched a video that showed this test to see a drain but not sure my meter will register correctly?

Ended up using the leads to check voltage and it drops slowly like every 5 minutes. Like from 12.47 to 12.46. I undercooked the voltage reg as some videos show this can cause a drain, and also disconnected the positive alternator wire as a different test but neither stopped the drop in voltage after checking for several minutes each.
At this time I started pulling fuses and would wait 5 minutes to see if a drop occurs. So far the cigarette lighter fuse, and acc fuse do not stop the battery from falling slowly. Tomorrow I will try the additional fuses.

Hopefully can get yo test the battery Monday.. I hate electronics!

[midlife]

Even your multimeter is set to 200 ma, you should still be seeing 10 or so ma.  Your reading of 0.00 implies 5 microamps or less.  My guess is that your meter is not working for DC current or you're not using the correct lead positions on the multimeter.

[dave6768]

Turn something on with your meter connected like an interior light.  If you don't see an amp reading with that, your meter is not working properly.   Battery test will not tell you anything about parasitic drain.  I killed two batteries before I figured out I had a drain.  Mine turned out to be the radio in my 2006.

[Hipo giddyup]

Thanks Guys. I am getting a new meter today to be sure. looks like it drops .07 a every 24hours.

I have the optional trunk light installed, and thinking it could be staying on, I removed the bulb - notta. Also verified the simple things are off, like checking the glove box light, left the VR unplugged, checked the Stator of the ALT for juice - I hear a bad diode can show there- and disconnected the amp I have from the + side of the battery. Still seeing a drop. Hopefully I'll find the culprit. The only piece of wiring left that's original is the under dash, could be a short somewhere , maybe a frayed wire? Who knows. I have been driving the car frequently since 2017 with 0 issues until now. 

[Hipo giddyup]

OK, so I charged the battery up again , it was at 12.57v, and started my test with a new meter that I picked up from Harbor freight. On the Settings that I've seen online, I believe it was a 10 amp setting at first, it registered .01 or .02 using the probes between the negative post of the battery and the negative cable. And then was able to lay the meter on the windshield and start pulling fuses. I pulled the accessory first which led to nothing, pulled the instrument fuse,Lon change,. And then I noticed that I was right underneath of the rally pack harness. I unhooked the blue wire which I believe is the power wire to the rally pack clock and the number on the meter leveled out to 0.00. I assume that the rally Pack clock maybe has malfunctioned and pulling more power than normal? It is a new quartz movement clock replacement.  Let me know if there's another test or another way to check this with the meter. I would like to isolate the Rally pack clock, but I'm not sure how to see what type of power it is drawing, maybe there is a test someone knows for this? Thanks again for anyone's help.

[Hipo giddyup]

Also, it's been 24 hrs since unhooking the rally pack power- blue wire- and the battery is maintaining 12.56 volts. It's either the wiring to the clock or the clock itself I guess??

[jwc66k]

Also, it's been 24 hrs since unhooking the rally pack power- blue wire- and the battery is maintaining 12.56 volts. It's either the wiring to the clock or the clock itself I guess??

That's why I have a battery disconnects on my 65 and 66 Mustang GT Fastbacks that both have Rally packs. They sit.
(Plus I have a trickle charger on the battery.)
Jim

[midlife]

Your reading of 0.01 to 0.02 indicates 10 to 20 milliamps, which is just fine.  Clocks continuously run, typically about 10 milliamps.  That should allow you 1-2 weeks of the battery sitting after a full charge and still have plenty of oomph to turn over the starter. 

2 weeks is 14 days, or 336 hours.  With 20 milliamps, that's 6.7 amp-hours.  A typical car battery has about 48 amp-hours. 

Either start the car once a week and drive it so that the battery charges, use a quick disconnect, or a trickle-charger.
The fact that your battery drains that quickly suggests that the battery is on its last legs.

[Hipo giddyup]

Thanks Midlife for that explanation. So the older battery was 7 years old, and honestly why I didn't check it. Its good to see that the clock should be pulling the 10/20milliamps so that makes sense. I wasn't sure what it was supposed to use. Now I will need to check the new NAPA battery out as it could be the issue. I have had the car sit for a week or two with no issues starting so something is up. And, the quick disconnect isn't a bad idea since this car has the clock.

Thanks everyone for your help here!