The battery is only useful in command stuff for dropouts going across switches and/or dirty track as a rule. Frequently, the tender with the sound system drops the sound even though the locomotive continues, that's when the battery comes in handy. If you don't have those issues, you don't need a battery for command only use. I have some steamers that drop sound regularly, others seem to be fine. If nothing shows up checking rollers and wiring, I add the battery. I happen to have lots of them here.