It might just be worth it to do that…testing was done by a mechanic? If not, I think at this point it’s worth the diagnostic fee to do it professionally before buying a new battery…3 miles isn’t a very long drive, and the jump could’ve brought the battery higher than what the alternator would have brought it up to allowing the easy restart, without those readings on your meter, who knows?
Early Christmas present, get her one of those portable charging packs, then you won’t have to drive out to her all the time
Bravesfan314, I had the same thought on the charging pack. I need to set up
some experimental protocol. I see a published paper coming out of this
(Maybe I can finally get tenure). I am going to get her a portable charge
pack and send her to work. Each day she can park in a different position:
forward facing, rear facing, sideways taking up 2 or 3 spots. Of course she
will have to do multiple replications so that we can get some
scientifically sound data. I wonder if we can get some of the guys from MIT
to work with us on this. Maybe we can get multiple GMC Envoys with the same
age, mileage, and battery to perform the same experiment across the
country. I know that if we get this all set up, I can get a government
grant written. I can finally fund my position. I will keep you up to date
as I run the experiment.
OK the motion detector was a shot in the dark but at the time, it was the only thing that appeared different.
I kind of suspect that battery has an intermittent short although it is odd that it shorts under the same circumstances all the time.
I do have another theory that would involve a weak battery and is related to her driving patterns. If she is going to work on very cold mornings and returning home in warmer weather, then it would be possible that she runs the blower fan at its highest speed, with her headlights on and at slower speeds. People think that an alternator will charge a battery under all conditions but that is not true.
Alternators are much more efficient than the old DC generators were and they will have a + charge at idle IF there aren’t other loads on it such as the headlights and heater fan. With both of those on, the alternator can still be negative at idle and low speeds.
When she returns home in daylight so only the DRLs are on and the blower fan is on a lower speed, this charges the battery. A good battery should be able to handle these situations unless the commute is particularly long.
BTW I do have one more question. When she needs a jump start, is the battery low and the starter tries to turn, turns slowly, or makes a lot of clicking sounds or is it so dead that absolutely nothing happens, no sounds or lights?
We switched cars today. We leave at around the same time and we both drive
about 10 minutes to opposite sides of our small town. It was cold this
morning and I left all of the settings the same as when she brought it home
last night. I left the blower on high, the seat warmers on, and with lights
on. She gets up to 55 mph for 2 miles of her trip. My trip is always at
slow speeds through town.
Now it’s warmed up and I left work to go get a bite to eat at lunch. No
problems with starting.
Most of the time the battery is completely dead when needing a jump. When
she called the other day, for the first time, it was making sounds when she
tried to start it.
Making sounds, thats good. In 50 some years of driving, twice I have had a battery that had a hairline crack somewhere inside it. It would randomly appear dead, and by dead, absolutely no response. I’d jump start and everything would be fine for awhile, then it would happen again. In each case, the incidents would become more frequent until I just replaced the battery. One of those batteries was less than a year old.
Also had this on a third battery but that was due my hamfisted (now ex) son in law that cranked down too hard on one of the terminals and broke it internally.
I am now at the point that the first time a battery goes dead on me, I replace it. But first I do make sure there isn’t another issue, i.e. charging problem or heavy parasitic drain.
You do not need to have arms like gorilla… guess how I know
Somehow all my 8mm and some 10mm wrenches happen to break on me, I simply do not “feel” torque much up to some point
OP is probably going to have to have a battery current drain test done both parked at home and parked at the Taco Bell to resolve this. It’s something a diy’er with some DVM experience can usually do, takes about 5 minutes to do.
I don’t have time this week to run the current drain test. Until then, I
got her one of those small jump start packs. She is going to try different
parking positions around the parking lot. She is now excited about her
battery running down as her coworkers and manager have there own theories.
One of them involves low level wind patterns.
Results of day one experiment with changing parking positions: She left for
work in the cold and before daylight, parked on the opposite side of the
building. Car started fine this afternoon. She will do this for the next 3
days to test for consistency. She then wants to back into her old spot for
three days and finally pull in forward normally as she had been when this
started. I have now started a pool as to whether this crazy experiment will
yield any valid results or just amuse my daughter for a few days.
Good for your daughter for doing the scientific experiments necessary to resolve this conundrum. It’s much easier to just give up, or hope the problems goes away on its own, but maintaining that kind of resolve to want understand will pay off in spades her whole life. It will be interesting for the rest of us to know the final result; be sure to keep us up to date on the intermediate results OP.
I will keep you up to date
