Battery Minder Confuses Electric Steps

I've had a Battery Tender brand connected to my chassis battery for a year now with no problems as you describe. It is plugged into the old television outlet in the front dash and is hardwired to the battery, so when the rig is plugged into shore power or the genset is running, it is trickle-charging or conditioning the battery. But, that 120VAC outlet has an auto shut off when the engine is cranked/running, (originally designed to keep the television from working when underway) so the Battery Tender is not competing with the alternator if I'm running the genset going down the road.