lithium batteries

[robert]

Are they compatible with a stealth on board charger and with a 300 XS Optimax? Any downsides out there?

 

[XXXR2001]

Depends on the type charger and which battery you get. Yes with 300xs. Yes there are downsides. They're expensive and somewhat sensitive to over charge and discharge unless you buy one of the very expensive ones with built in circuit board protection. With the 300xs, charging should not be an issue if you're using it for cranking.