Altenator upgrade

[CaptRich]

Hello, has anyone upgrade from the oem 55 amp to a higher out put 65 or 70 amp and how do you get from the 4 wire to two upgrade. 1996 23 sr , 5.7 l 260. the old one is not charging as it should. two batteries.

[shrew]

What size boat? I doubt you have enough load to need a higher amp alternator. If you want to charge the start and house bank while underway, install a BlueSea Automatic Charging Relay (ACR)

An ACR will draw from the start bank at start. Will draw from the house bank at rest, and will isolate the starting bank to protect it from being drawn down.

A higher amp alternator will introduce heat. If you have a large draw you'd be looking at an external charge controller.

Likely you're fine replacing the alternator with the same setup, using the internal charge controller on the alternator and installing a ACR if you want to charge the house and start bank while underway.