The JL uses an AGM H7 main battery — replace it with AGM, not a flooded lead-acid, or the start-stop system will fail and the BCM will log faults.
The 2018+ Wrangler JL ships with an AGM H7 (BCI group 94R) main battery — typically 80 Ah and 850 CCA. eTorque trims (2.0L turbo and 3.6L with the 48V mild hybrid) add a small 12V AUX14 auxiliary AGM battery rated around 200 CCA, plus the separate 48V lithium-ion pack that handles the mild hybrid functions. The 48V pack carries an 8-year warranty and is not a DIY part. The auxiliary 12V AGM and the main H7, however, are both owner-serviceable.
Use AGM only. The JL's body control module is configured for AGM charging voltage and current profiles. Drop in a flooded lead-acid battery and the BCM will overcharge it on highway runs and undercharge it during ESS stop events, which kills the battery in months and throws "Service Stop/Start System" warnings. Quality H7 AGM options include Mopar OEM (Interstate MTX-94R/H7), Odyssey AGM94R, Optima YELLOWTOP DH7, and the OEM eTorque part 56029720AA. Expect to pay $250–$350 for a quality H7 AGM.
The auxiliary battery on start-stop and eTorque trims lives on the passenger side firewall under a small cover. It powers electronics during the ESS engine-off pause so cabin power, infotainment, and HVAC don't drop out. When it fails, ESS stops working and you'll see a service message — but the truck still runs fine on the main battery alone. Replacement AUX14 batteries run $90–$140.
After replacing either battery, the BCM needs to register the new battery so it can manage charging correctly. On non-eTorque JLs the system usually self-relearns within a few drive cycles. On eTorque trims, a Mopar dealer or aftermarket scan tool (Topdon, Autel, wiTECH) is recommended to perform a battery registration. Without registration, the alternator may not properly charge the new battery, shortening its life by half.
| Part | Vendor | Est. price |
|---|---|---|
| Main AGM H7 battery (94R, 80Ah, 850 CCA) | Interstate / Mopar | ~$280 |
| Mopar OEM eTorque main battery | Mopar | ~$320 |
| Auxiliary AGM battery (group 400, 200 CCA) | DieHard / Super Start | ~$110 |
| Odyssey AGM94R H7 | Odyssey | ~$340 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.