Don't Pack Lithium AAs in Your Flash Bag — Any Brand, Any Speedlite

Before you grab those Energizer Ultimates from the camera bag — stop. Canon just issued a formal service notice against lithium AA batteries in Speedlites, but this isn't a Canon-specific quirk. Check your Godox, your Profoto, your Nikon flash manual and you'll find the same warning buried in the same small print. Lithium AAs push higher voltage than alkalines, and flash units are calibrated for alkaline chemistry. The result isn't just a voided warranty — it's potentially fried circuitry mid-job. Use Eneloop rechargeables and move on.