Help diagnosing a battery

WOODY2

Adventurer
I’ve had similar no-starts on my 2014 and found a barely perceptible movement in the negative cable clamp. It sounds to me like you are restoring a bad connection when you move batteries. When you say the terminals are tight, have you also checked the “other end” of the negative battery cable? It might be loose or corroded.
"The other end" is one of the most overlooked connections.
 

dreadlocks

Well-known member
I've had a ground strap fail between the transmission and the chassis.. was a bugger to find.. engine ground ended up going through the throttle cable which the starter happily burnt up.
 

shade

Well-known member
If the wiring all passes inspection (visual & with a meter while moving it around), I'd consider the Genesis system to be suspect.

It doesn't look like it'd be difficult to rearrange the wiring to completely remove the Genesis stuff from a single battery, and return the system to OEM configuration. If that solves the problem, a bad solenoid or something else in the Genesis system may be the problem.
 

WOODY2

Adventurer
Simply being tight isn't the solution, connections must be shiny clean as well. I have seen issues where there was significant corrosion and terminals were cleaned but the issue was in the cable just adjacent to lug, ie: out of sight. Temporarily isolating the Genesis will tell you a lot.
 

JDaPP

Adventurer
10.94, 11.11 and 11.2 on the starts. Retightened all connections. Did have one area where the negative cable was being pushed down by the engine plastic cover that I've rectified.
Unfortunately I'll have to check the other end of the connections when I get back off of a work trip. I greatly appreciate all the help and I will let you know what I find when I get back to my work trip. Thanks.
 

rayra

Expedition Leader
seconding grounding issue. Check your main battery grounds and starter / solenoid connections. Clean the connections.
 

luthj

Engineer In Residence
10.9 is acceptable, but marginal, especially if the battery is above 50F. High resistance connections will often get warm after cranking, so you can also try feeling about for a warm terminal or wire section.
 

JDaPP

Adventurer
So got back from work trip, but had a quick turnaround to move across country. Checked all connections and still have not noticed anything unusual, did some rewiring of switches, and added a grounding cable from the body to negative terminal. Have had no further issues starting BUT about 4 days ago started noticing a rotten eggs smell. Smell was coming from house battery and noticed vent was bubbling/hissing. Took both batteries in, house battery was bad, starting battery initially showed good but as they charged it the cca dropped so they replaced both of them.
Good news is 2 new batteries but I am concerned how 2 batteries would go bad in about 2.5 years? Any thoughts or suggestions to make sure it doesn't happen again?
 

luthj

Engineer In Residence
What specifically was wrong with the house battery? Shorted cell? Deep discharging can cause cells to fail that way. But vibration and age also play a role.

Walmart batteries are not very high quality. About 7 years ago I had a walmart starter battery fail in a similar manner. When one of the cells shorts down, the battery goes from 12V nominal to 10V nominal. The means that when the battery is charged at ~14V, its similar to charging a 12V nominal battery at ~16V, hence the off gassing.
 

JDaPP

Adventurer
They didn't specifically say but the their system showed it at 8v and indicated it was bad. Sounds very similar to your shorted cell. I have been very careful about not running it too low and I honestly only get to camp about twice a year anymore so not heavily used either. not surprised that Walmart battery quality would not be the best.
 

luthj

Engineer In Residence
I have seen terminal studs twisted enough to break the internal bus bars, shorting a cell. But sometimes it just happens with no obvious cause.
 

rayra

Expedition Leader
I'll check the connections but they are always tight/the first thing I check. Never been loose when I checked them. Below is a picture of the Genesis setup. Based off the below picture, any thought on where I should look for ground issue?



View attachment 551108

Genesis website
Not the battery post / terminal connections, the connections at other end, where the negative / ground cable attaches to the frame or engine block.

Also, what general part of the country / corrosion issues / condition?

And 2-1/2yrs on some regular SLA batts, coinciding with peak winter or summer temps, about time for a new battery.
 

rayra

Expedition Leader
I’ve had similar no-starts on my 2014 and found a barely perceptible movement in the negative cable clamp. It sounds to me like you are restoring a bad connection when you move batteries. When you say the terminals are tight, have you also checked the “other end” of the negative battery cable? It might be loose or corroded.
yep, terminals can be tight and still loose on a battery post. Likewise if overtightened, a side terminal battery connection can be torn loose. Sure the cable is tightly bolted, but to a terminal whose internal connection is now damaged.

These are easy mistakes to make, in both creating the damage in the first place and trying to diagnose the issue.
 

JDaPP

Adventurer
Not the battery post / terminal connections, the connections at other end, where the negative / ground cable attaches to the frame or engine block.

Also, what general part of the country / corrosion issues / condition?

And 2-1/2yrs on some regular SLA batts, coinciding with peak winter or summer temps, about time for a new battery.
Checked both side of the connections best I could although I have not really gotten a close look at the engine/frame side.
Jeep has lived its life in Florida and San Diego. Garage or carported 95% of the time. Very little corrsion anywhere on the vehicle.
I am heavily leaning towards bad battery at this point but intend to keep monitoring to see if it gives me any additional issues.
 
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