Best battery replacement for Jeep Grand Cherokee SRT?

Question

Hey everyone, my 2018 Jeep Grand Cherokee SRT is starting to show some signs of struggle during cold starts. The electronics are acting a bit glitchy, and I’m pretty sure the original battery is finally on its way out. Since these rigs have so much tech and that big 6.4L HEMI to crank over, I don’t want to just grab the cheapest option at a local parts store.

I’ve been looking into AGM options like the Odyssey or the Interstate MTX series, but I’ve heard mixed things about fitment because of the battery location under the passenger seat. I definitely need something with high Cold Cranking Amps (CCA) because it gets pretty chilly where I live, and I want to make sure the replacement can handle the high vibration and accessory load of the SRT trim. Budget isn't a huge concern—I'd rather pay more for reliability than get stranded.

Has anyone here swapped their battery recently? I'm curious if you went with an H7 or H8 size and if you noticed a difference in performance or longevity. What specific brand and model would you recommend as the absolute best reliable replacement for a daily-driven SRT?

CynthiaMom · Accepted Answer

Check out the H8 size if you want more juice; it's a tight squeeze but worth the extra capacity. I personally found the Interstate Batteries MTX-49 H8 AGM and the NorthStar NSB-AGM49 Group 49 (H8) much more reliable than the Odyssey in my experience.

grgtsnflog · Answer

Similar situation here—I went through this exact struggle with my 2017 SRT last winter. Honestly, I’ve learned over the years that while the H8 size offers more capacity, the fitment is such a headache in that tight compartment under the seat. I spent way too long wrestling with the brackets!

I eventually decided to prioritize value and ease of install. I've been super happy with the Duralast Platinum AGM Battery Group Size H7-AGM 850 CCA. It’s been about two years of daily driving, and even on the coldest mornings, the 6.4L HEMI fires right up without those annoying electronic glitches. I also looked at the ACDelco Gold B24R AGM 36 Month Warranty Battery, but the Duralast was easier to grab locally. It’s handled the SRT’s vibrations perfectly fine so far. Just a quick tip: make sure you double-check the vent tube connection during the swap—it's easy to miss in that cramped space! Hope this helps!

pzrmqzrstm · Answer

For your situation, I've learned the hard way that you don't need to overspend. Unfortunately, I had issues with an expensive Odyssey that didn't fit right in that tight under-seat spot. Honestly, the EverStart Platinum AGM Battery, Group Size H7 (L4/94R), 12 Volt, 850 CCA from Walmart is the best budget-friendly move. It’s actually made by Clarios, same as high-end brands, but costs way less—around $180. I’ve run one in my SRT for three years with zero glitches during cold snaps!