You can put the HomeVac on the charging base though it's fully charged. The battery protection circuit prevents the battery from being overcharged. Once the HomeVac is fully charged, it will stop drawing power. 

If no one is at home for a very long time, it's recommended to unplug the adapter from the wall outlet for safety. 

Note: To preserve the battery’s lifespan, recharge at least once every 6 months when it is not used.