ShadowsPapa
Well-Known Member
- First Name
- Bill
- Joined
- Oct 12, 2019
- Threads
- 178
- Messages
- 29,091
- Reaction score
- 34,572
- Location
- Runnells, Iowa
- Vehicle(s)
- '22 JTO, '23 JLU, '82 SX4, '73 P. Cardin Javelin
- Occupation
- Retired auto mechanic, frmr gov't ntwrk security admin
- Vehicle Showcase
- 3
- Thread starter
- #211
Actually, there is.This is exactly my point. Maybe there isn’t enough full voltage charge time in its factory set points.
Unless the battery SoC is at or near 100%, the voltage stays up above 14 volts. I have only ever seen those voltages in the mid 13s to upper 12s when the batteries were at 100%, cruising on the highway, no real electrical load to speak of.
Put the off-road pages up on the radio and watch the voltages - if your batteries are under 12.5 you aren't going to see system voltages under 14.
HOWEVER, I'm beginning to wonder if the batteries Jeep is using are needing voltages even HIGHER - my battery charger charges my JT batteries at higher voltages than my truck ever reaches.
And if you look at the manufacturer's recommendations for their specific batteries, some vary a bit - some suggest a max of 14.6 or 14.7 while others suggest they need 14.8 to 15.0 volts absorption phase.
These Jeep just don't seem to be aligned with charging the batteries they are using, and charging two very different sized batteries can be problematic. One will reach "full" or saturation much faster than the other will.........
My truck recently sat for a good 10 days (been sick, not driving for well over a week). I decided to spend what energy I had to check the batteries.
Still together in the stock parallel configuration, still connected to truck's systems, meaning some parasitic draw from the electronics, the combined reading was 12.19 volts.
I pulled the negative cable from the aux battery off the top of the IBS, isolating the batteries from each other. (and the AUX from the truck's electronics which was interesting because when I opened the door, everything still functioned normally)
The AUX battery by itself read 12.29
The crank battery (apparently still feeding the truck's electronics!) rear 12.26 volts
Weird - together it was just shy of 12.2, independently they were each over 12.2 and even though the negative was pulled off so the aux battery would be isolated, the crank battery still feeds the truck electronics.
(which begs the question - why will the vehicles sometimes not start? The CRANK battery still feeds the truck's electronics - the crank positive is on N2 which is directly connected to N3 through a fuse, which then feeds through the closed PCR contacts, and up to N1 - the system electronics. So if the aux battery is removed, the crank battery still feeds the truck's electronics!)
Anyway, with the negative cable from the aux battery pulled off the IBS, I charged it using my charger's 2 amp setting. It only took a couple of hours for it to reach 12.8 volts, 100% charge! And that's at the charger's lowest setting. Keep that 2 hours in mind.........
I then moved the charger's negative clamp to the top of the IBS on the crank battery and set the charger to 10 amps.
Independently, it said the battery was 40%. Interesting as when both batteries were connected together, it said they were 31% state of charge. Yet apart, the crank battery was 40%.
I let it run on the 10 amp setting. The charger went through all of the phases and didn't get through the completion phase to rest for several hours.
At 2 amps the aux battery charged in a couple of hours, through all phases, including completion and even rest.
At 10 amps, the crank battery took all day to charge - all phases, to the rest phase.
The net result - I hooked things back up, we needed some supplies (needed more food that Yawnie would eat and some OTC meds for me, etc.) and when I came to the first stop sign at 1.1 miles away, I didn't push the brake pedal hard enough to see if ESS would work or not. The next stop sign was under 1/4 mile away, so from home to the second stop sign was about 1 1/4 miles from home, and ESS worked fine. In fact, it worked the entire remainder of the morning. And the truck's voltage stuck right around 14.3 which I found really interesting considering there was little load, batteries were charged - but the AC was on so that was likely a power need. I expected it to be in the 13s.
I still believe charging 2 very different size batteries is problematic, and I'm not convinced the PCM is configured with the proper charging sequencing for the specific batteries used but I need to check my log dumps to get more information to see that the configurations are for various IBS conditions.
Sponsored