The service manual (rabird) and the annotated photo (Douggro) help with identifying all the parts so thanks guys. The battery is reportedly new. I bought it from a friend who said it was a new spare, so maybe, maybe not. When on shore power, should the battery charge? Regarding the time delay relay: When running on shore power, and heating, the voltage on the top red lead (and bottom red lead) of the timer delay relay is 11.2VDC and goes up to 13.2Vdc when the heater cycles off. The voltage on the white leads are about 10.9 when heating and about 10.6 at the furnace switch. I still haven't yet tried switching to battery power. Is it ok to switch to battery when the heater is running, or should I wait until it cycles off?