I have a two battery banks on my boat.

The largest in terms of capacity is the house bank, which is made of deep cycle batteries that can be charged at up to 14.82V.

The engine start bank can only be charged at up to 14.7V.

My goal is to charge my house bank at the highest voltage in order to reduce engine run time, and without damaging my engine bank.

My plan is to charge the house bank at 14.82V and use a relay to combine the banks when the alternator is charging.

Can I use a diode with a 0.2V or so forward voltage drop? Would it require a heatsink?