[speedygonzales]

A tight (new) engine coupled with a less than new battery at low temperatures can do it.

Put a voltmeter across the battery terminals while someone cranks the engine over. Anything lower than 11 volts isn't going to cut it.

You could always try another known good battery for a test.

Also be leery of connections that have not been removed and cleaned for some time. Like ground straps to the frame. Etc.... I found the best charging on mine when I added a separate ground to the engine from the battery and separate power connection from the battery to the alternator directly.