I have a 1966 Hatteras that I am converting the house bank from lead acid to lithium. The boat is wired as follows: The starting bank is on the port side and is directly charged from the port side alternator (Multi II when on shore power). The house bank is on the starboard side and charged directly from the starboard alternator (Multi II when on shore power). I want to charge the new lithium house bank only from the starboard alternator via a Smart Orion but not want to use the starting bank (AGM) as a buffer bank. My worry is that the starting bank will be getting overcharged due to being connected to 2 alternators at the same time. My question is, can I charge the house bank directly from the alternator through an Orion Smart without using a buffer lead acid battery? If so, are there any down sides to this method?
Answered many times, a search for Orion buffer battery would show this.
The Victron Orion units are battery to battery units and the alternator output must have a battery. Look in all the install manuals, they show the alternator charging the starter battery and the Orion charging the house battery.
When people have connected an Orion direct to an alternator they have reported voltage swings as the alternator voltage regulator interacts with the voltage control on the Orion input. Both controllers are trying to control the same voltage by varying the same current. Not saying this will definitely happen but it is seen frequently. A battery decouples supply and demand current and buffers the voltage / current response.