What is the best lithium battery tender for a Chevrolet Corvette C8 E-Ray?

For a C8 E-Ray, you need a battery tender that is explicitly designed for lithium batteries. The general consensus is to use a CTEK lithium-compatible maintainer. CTEK actually manufactures the official GM Corvette-branded chargers, so buying a CTEK directly gets you the same quality without the "Corvette tax" ⁵.

Here is what you need to know for the E-Ray specifically:

The Lithium Requirement and Voltage Limits The E-Ray uses a 12V lithium-ion starter battery with built-in circuitry and very narrow charging parameters. According to a GM engineer at Carlisle, it is critical that your tender has a symbol or text stating it is lithium-compatible ¹. Standard lead-acid maintainers will occasionally spike the voltage to counteract sulfation, but if a charger pushes over 14.5V into the E-Ray's battery, it can permanently damage it ¹. Standard CTEK units are known for safely staying below 14V ⁶.

Note: You may hear some owners say they use their standard C8 Stingray charger on their E-Ray without issue, but the technical consensus strongly dictates using a verified lithium charger to avoid risking an expensive battery replacement.

How to Connect It (Difficulty: Easy)

1. The C8 is pre-wired for easy charging. You just plug the tender directly into the 12V cigarette lighter-style outlet located on the passenger side of the front trunk (frunk) ³.
2. If you buy the OEM GM charger, it comes with the 12V cigarette adapter plug. If you buy a standard CTEK unit off Amazon, you will likely need to purchase the CTEK 12V cigarette lighter adapter plug separately (usually around $15-$16) to connect it to the frunk port ⁵.

Grab a lithium-specific CTEK, get the 12V adapter pigtail, and plug it into the frunk. The charger's automatic circuitry will handle the rest.