Optima Batteries YellowTop D34/78 Dual-Purpose AGM Battery

It fits the Tacoma battery tray but is not a factory drop-in. The 2nd-gen Tacoma (2005·2015) specifies a Group 24F battery; the D34/78 is Group 34/78, a different physical footprint. The battery physically sits in the tray, but the OEM bottom-bar hold-down bracket designed for Group 24F does not reach the Group 34/78 tabs without modification · most Tacoma owners source a hold-down bracket extension or reposition the existing bracket. This is a documented community upgrade, not a straight swap. Owners who want a factory-spec replacement should buy a Group 24F AGM instead.

Dual-purpose means the YellowTop is designed for both starting current (like the RedTop) and repeated deep cycling · the ability to discharge partially and recharge without accelerating sulfation. The RedTop is optimized purely for starting current and is not designed for repeated deep discharge; the YellowTop trades a small amount of peak CCA headroom for significantly better discharge/recharge cycle tolerance. The practical difference matters if the vehicle has heavy accessory loads (winch, high-output audio, overlanding gear) that can draw the battery down before or between starts.

750 CCA is the SAE J537 cold-cranking amp figure, published cleanly by Optima as the primary cranking spec. There is no PCA or 'Power Cranking Amps' substitution on the D34/78 · the 750 figure is directly comparable across battery brands. The OEM minimum CCA for most Group 34/78 applications (GM full-size trucks and SUVs, Chrysler vehicles) is typically 600·700 CCA, so the D34/78 runs with meaningful headroom on those applications.

Yes · the D34/78 YellowTop carries the Amazon add-on item flag as of 2026-05-27, meaning it requires a qualifying order to purchase standalone on Amazon. The battery is widely stocked at AutoZone, O'Reilly, Advance Auto Parts, Walmart, and Costco (seasonally) where the add-on restriction does not apply.

The Amazon listing for Optima Batteries YellowTop D34/78 Dual-Purpose AGM Battery carries a California Prop 65 warning. California requires this warning on a very wide range of manufactured goods — including rubber, vinyl, plastic, and metal automotive parts — whenever trace exposure to any of roughly 900 listed substances (commonly phthalates or heavy metals) is possible, regardless of whether the specific product poses a meaningful health risk. As a passive accessory, Optima Batteries YellowTop D34/78 Dual-Purpose AGM Battery has no Safety Data Sheet, so there's no chemistry breakdown to translate beyond that.