Can I Charge Two Battery Banks From One Alternator?

Question:

Hi PYS, I have been watching your team on YouTube, and it's been beneficial; I have a problem and a question. I have a new 160 amp high output alternator that I was hoping to use to charge two 750 amp start batteries and a 200 amp lithium house battery using and 200 amp argofet one post feeding the start batteries and one post feeding a DCDC Victron charger into the house battery. Is this viable? Do I need a smart regulator? Any help would be appreciated, Robert.

Answer:

Hi Robert, Thanks for reaching out to PYS with your question. When dealing with high output alternator such as your 160a, it's always best to utilize an external regulator to ensure safe and efficient charging of your batteries while underway. As your start batteries and house batteries will have different chemistries, they must be kept separate; using an isolator run line with a DC-DC charger wouldn't be viable due to the voltage sensing requirements on both devices. It might be worth considering connecting the regulated output to your main house battery and then charging the charge from the house battery via DC-DC chargers to both engines.