AGM Starting Battery Voltage 2014 Grand Cherokee

Sorry about my error. Yesterday only part of this thread loaded.

Your scenario is perfect for your AGM battery. Would not be surprised to see it last ten plus years.

CA Traveler wrote:
...

But I did find a oil pressure gauge buried in the menus. :)

Keep digging in those menus and you will find the volt meter :)

And for clarity I could only see the clamp on ammeter from the back seat which is why DW drove.

My Fluke cost more than 7 cents and there is no dash voltmeter. :B

But I did find a oil pressure gauge buried in the menus. :)

Ductape wrote:
Dash gauges are frequently programmed to meet customer expectations, the marketers apparently think real data will confuse drivers.

At some point the made a switch from numbered gauges to scan gauges. The theory is that you can quickly scan the gauges and tell if something is wrong without analyzing any data. Normal operating range is in the middle of the gauge. High and low are abnormal readings.

It's like the engine temp light in the movie Airplane! - "A Little Hot"

Dash gauges are frequently programmed to meet customer expectations, the marketers apparently think real data will confuse drivers.

Sadly they are probably right for the majority.

Car dashboard voltmeter...

"What voltage does the meter read?"

"Yes"

Battery voltage must be read at the battery terminals suing a meter that cost more than seven cents to stamp out.

According to my car's dashboard gauge, when I turn the key to "on" I have a tad over 8 volts. Yes. Absurd

I measured the charging one time with DW driving so I could see the clamp on ammeter. 14.4V and the battery amps briefly exceeded the 40A scale. I've seen 14.6V charging.

I'll see what I can do about some of the above charging suggestions. I'm stalling on pulling the battery because the access is difficult at best since it's located under the passenger seat. It's so bad that jumper posts are located under the hood. But I can pull the negative cable and isolate it from the car for testing.

It's a Mopar AGM group H7A 800CCA 80AH. It's completed enclosed with a hose attached for ventilation.

My AGMs are at 13v full and resting. Generally higher than Wets at 12.7 when full. So it looks like that 12.6 on rebound is quite low.

If it works ok, the question is how much longer? No idea. So it is all about risk of not working and when for some scenario, if you should get a new battery right away.

I think those voltages considering a 8 to 9 amp load are fairly low, , and the rebound to 12.6 is certainly better than not rebounding that much, but could easily be indicative of a sulfated battery.

I'd try and restore capacity/desulfate by draining to to 12.1v rested, under a 10 amp plus load, then charging it at 25 to 30 amps until 14.7v is reached, and hold it until amps taper to 0.5% of the amp hour capacity which might take 4 to 12 hours. Perhaps even longer.

Once battery cools I bet it would hold higher voltages under the same loads.

How much of its capacity will actually be restored is an unknown.

If the relatively high amp recharge from a well depleted state does nothing, I would then boost voltage to 15.5v after the regular full charge, for several hours, monitoring it closely for excessive heating.

My Northstar group 27 AGM, 930CCA, 90Ah capacity will, at 700+ deep cycles and 4.5 years of age, easily maintain 12.6v+ under a 10 amp load until it depleted 15 to 18Ah of its original 90.

its full charged resting voltage used to be 13.06v. Not sure about now as it never gets a chance to rest, but this particular battery loves the high amp recharge from a well depleed state and It always sems to restore performance, which I judge by voltage held under X amount of load and X amount of Amphours removed, and much observation of these variables throughout those 700+ deep cycles.