Background:
I have a late 90’s fishing boat. It’s has a 2 stroke motor and 4 stroke kicker. Both motors charge the FLA battery with a stator and rectifier.
The motor manufacturer very explicitly states they can only be hooked up to an FLA battery. The main motor does not like low voltage and has a tendency to burn up rectifiers if the voltage of the FLA drops too low. Essentially the electrical system needs some resistance.
I run all my electronics off the cranking battery and I want to keep it topped off to extend run time without the voltage dropping too low.
Plan:
I would like to add a LiPO4 battery and connect it via a 12-12|18 isolated DC-DC charger. Shore power would charge the LiPO4 and via the DC-DC it would keep the cranking/house battery charged. When out on the water the LiPO4 would continue charging the FLA giving additional amp hours for the system.
Question:
The 12-12|18 DC-DC charger needs to disconnect the FLA from the LiPO4 when the motor is running so the LiPO4 resistance isn’t inherited in the charging system burning up the rectifiers. Obviously the motor doesn’t have a smart alternator. Can the Victron DC-DC charger be set up to disconnect from the FLA quickly upon starting the motor?
Thanks in advance for any information or ideas you can provide.