freebird_78
Well-Known Member
- Thread starter
- #1
BACKGROUND:
'21 JTRD. Been having intermittent AUX battery issues from day one. Nothing major, never failed to start or anything like that. Since I have Tazer, I disable start/stop, so really, had I not been monitoring the charging patterns, I probably wouldn't even know there was a "problem". However, start/stop would almost never be available as it sits, if I did care to use it. I'm VERY impatient, so the only way I would bother with going to the dealer and dealing with the inevitable BS about this would be if it left me stranded, or if I did want to use start/stop.
I have a battery tester and have measured (and reported on this forum) what I've been seeing. Bottom line, the main battery has and still is testing "good" and has around 8mOhms of internal resistance and about 750 CCA capacity (despite the 700 CCA rating). Similarly, I've been testing the AUX battery. Despite testing "good", the internal resistance always tests in the 13-16mOhm range, which is high for AGM. Capacity is testing to be 185 CCA, despite the 200 CCA rating. I've done the IBS reset, and that seems to work past the 5 drive cycle re-learn, but not too much beyond it, before reverting to a constant 14.0V charging voltage (rather than the variable 12.7 - 14.7, load dependent charge voltage), and showing auto start/stop "charging". The weather is warming up, so things like heater grid, DEF heaters, etc are no longer a factor. My normal commute is about 40 minutes, so short cycling isn't really in play. A recent 6 hour road trip still resulted in the same behavior.
EXPIRIMENT:
After lots of research, it appears that the stock AUX battery is a slightly modified 14-BS motorcycle battery. Physically the same size (more on that later), same capacity (again, more on that later), same terminal orientation, and similar terminal posts.
As it turns out, my quad uses a 14-BS, and I recently replaced it with a new AGM.
After my road trip (referenced above), I decided to go ahead and run the 14-BS AGM experiment. The new 14-BS tested at 285 CCA (with a 220 CCA rating) and about 6mOhm internal resistance. Both a good bit better than the OEM AUX battery. Two very slight modifications were needed to swap the 14-BS in. First, the AUX batter compartment lid has a protrusion to hold the battery down, at least on the diesel. This protrusion sits roughly in between the two terminals. While the overal dimensions of the 14-BS are identical to the OEM AUX, this particular area on the 14-BS is about 1/4" taller than OEM. Simply grinding down the hold down protrusion by that 1/4" solved that. If I have to revert back, I'll simply add a small piece of foam to the OEM AUX to maintain a tight fit. The second very minor (and reversable) mod is to the terminals on the Jeep. The terminals are designed to engage the terminals on 3 sides, but the 14-BS terminal is about 1/4" wider, allowing only 2 of the three sides to engage. Simply bending one of the three tabs up flat allows it to engage properly. If needed to revert, simply bend the tab back.
RESULTS:
It's been a couple of weeks now, and I'm still getting "normal" charging/voltage, rather that sitting at a static 14.0V all the time. Enabling auto start/stop is showing it available every time I check. I've made it further than the IBS reset, to date.
It appears that an off the shelf 14-BS AGM motorcycle battery works just fine (actually better) than the OEM AUX battery. I'm gonna run it another month, just to make sure, then just buy a new one and return the one in the Jeep back to my quad. They're only about $60, so it's not a major investment.
'21 JTRD. Been having intermittent AUX battery issues from day one. Nothing major, never failed to start or anything like that. Since I have Tazer, I disable start/stop, so really, had I not been monitoring the charging patterns, I probably wouldn't even know there was a "problem". However, start/stop would almost never be available as it sits, if I did care to use it. I'm VERY impatient, so the only way I would bother with going to the dealer and dealing with the inevitable BS about this would be if it left me stranded, or if I did want to use start/stop.
I have a battery tester and have measured (and reported on this forum) what I've been seeing. Bottom line, the main battery has and still is testing "good" and has around 8mOhms of internal resistance and about 750 CCA capacity (despite the 700 CCA rating). Similarly, I've been testing the AUX battery. Despite testing "good", the internal resistance always tests in the 13-16mOhm range, which is high for AGM. Capacity is testing to be 185 CCA, despite the 200 CCA rating. I've done the IBS reset, and that seems to work past the 5 drive cycle re-learn, but not too much beyond it, before reverting to a constant 14.0V charging voltage (rather than the variable 12.7 - 14.7, load dependent charge voltage), and showing auto start/stop "charging". The weather is warming up, so things like heater grid, DEF heaters, etc are no longer a factor. My normal commute is about 40 minutes, so short cycling isn't really in play. A recent 6 hour road trip still resulted in the same behavior.
EXPIRIMENT:
After lots of research, it appears that the stock AUX battery is a slightly modified 14-BS motorcycle battery. Physically the same size (more on that later), same capacity (again, more on that later), same terminal orientation, and similar terminal posts.
As it turns out, my quad uses a 14-BS, and I recently replaced it with a new AGM.
After my road trip (referenced above), I decided to go ahead and run the 14-BS AGM experiment. The new 14-BS tested at 285 CCA (with a 220 CCA rating) and about 6mOhm internal resistance. Both a good bit better than the OEM AUX battery. Two very slight modifications were needed to swap the 14-BS in. First, the AUX batter compartment lid has a protrusion to hold the battery down, at least on the diesel. This protrusion sits roughly in between the two terminals. While the overal dimensions of the 14-BS are identical to the OEM AUX, this particular area on the 14-BS is about 1/4" taller than OEM. Simply grinding down the hold down protrusion by that 1/4" solved that. If I have to revert back, I'll simply add a small piece of foam to the OEM AUX to maintain a tight fit. The second very minor (and reversable) mod is to the terminals on the Jeep. The terminals are designed to engage the terminals on 3 sides, but the 14-BS terminal is about 1/4" wider, allowing only 2 of the three sides to engage. Simply bending one of the three tabs up flat allows it to engage properly. If needed to revert, simply bend the tab back.
RESULTS:
It's been a couple of weeks now, and I'm still getting "normal" charging/voltage, rather that sitting at a static 14.0V all the time. Enabling auto start/stop is showing it available every time I check. I've made it further than the IBS reset, to date.
It appears that an off the shelf 14-BS AGM motorcycle battery works just fine (actually better) than the OEM AUX battery. I'm gonna run it another month, just to make sure, then just buy a new one and return the one in the Jeep back to my quad. They're only about $60, so it's not a major investment.
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