Yes, the adapter that easy mentioned or an equivalent will work just fine. I did just that with a Honda 2000 before installing a true genset.
The extra $$$ for the companion generator doesn't buy you anything but a different plug - same capacity output of ~ 16.7 amps.
Look up your battery charger specs, you may even be able to get by with the 1000 generator since you're not looking to use ac, electric stove, etc.