95 Jeep GC sluggish crank

1995 Jeep Grand Cherokee Limited, I-6, close to 150K miles.

It cranks sluggishly. It actually starts ok because it's firing up on
what may be the first rev but it's really slow sounding. Battery was
about 30 months old. Spec. gravity thingy with the floating balls said
cells were only at 75% charge. I checked system voltage with engine off
and it was about 12 point something and with the engine running 13 point
something to 14. Seemed better for awhile so I was been watching the
vehicle's own voltmeter and it seems where it should be, near 14 with the
engine running. I also removed and emery'd the posts and cable clamps.

It started to seem sluggish turning over again in the last few days so
today I checked the battery cells and this time 50% to 75%. Okay, time
for a new battery so I got a pro-rated warranty replacement. After
putting it in I was hoping to hear a vigorous start. But nope, still
sluggish with the new battery. Of course the new battery, not coming
from a place that keeps them on trickle charge, isn't really fully
charged so I am hoping after it really gets charged it will in fact cure
the sluggish crank but is there anything else I should be looking for?
Do starters get "weak" or more likely just fail flat out?

Also, is it normal to get oddly high battery voltage readings immediately
after taking off charge, like in the 13's rather than 12 point something,
maybe from "surface charge" or something? I'm not charging it at any
great rate, just 3 or 4 amps....not much more than a trickle. SG
doohicky said the cells were at 75%.

---

OT but I'd gladly buy another new GC but I just can't see another 11
years of 15-18 mpg. I'm looking at maybe the Mariner Hybrid (if I can
find one to test drive). Toyota Highlander was in the running til I saw
that Consumer Reports said their tests had it only getting 22 mpg which
makes it kind of pointless given the expense.

Or I will give up and just get a car.

 

Remember cables have two ends....

Check all the grounds on both ends also. Please note that the mesh ground
straps rot from the inside...

 

Comments:
3-4 amps should be enough to charge it, but you need to make sure you
leave it on long enough - at least overnight. If it's still showing
75%, I'd suspect your hygrometer is not accurate. So you don't keep
chasing your tail with that, I'd take it to the place you bought your
battery and ask if they'd measure the battery with their hygrometer and
put that question to rest.

The surface charge thing is correct - voltage would start out higher
right after a charge and drop down after sitting. 13.5-14 is about
right with the engine running (charging it).

Once you eliminate the confusion factor of whether the battery is up to
snuff or not, if it's still slow cranking, then pursue that.

On whether starters can get weak rather than fail flat out, someone else
could better answer that. As billy ray suggested, you need to confirm
integrity of all connections in the high current path to the starter,
including grounds. Maybe the solenoid contacts are hight resistance,
but I think they usually just get intermittent (one time it will crank
right up, next time it just clicks) rather than constant sluggishness.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')