72vdc input on my 48vdc solar charge controller/inverter

I have an Outback Power ystems model 3648 grid-tie (or grid interactive)inverter with a 48vdc battery back up system.

I want to add a 72vdc wind power generator and thought I needed to add another charge controller to handle to input. I was told today by a solar guy that I could hook the 72vdc from the wind turbine directly to the batteries because the excess power created at the batteries will be converted instantly to 120 vac by the inverter and will be sent to the grid.

I don't know much about dc voltage and wanted to know if this is indeed true. Can I hook up a 72vdc input charger to a 48vdc battery system?

Thanks,
Dan