I recently purchased a 2006 Hunter 38 which has the factory-installed 60 amp alternator on my 40-horse engine. This is woefully weak when trying to spend the night on the hook or a few days away from shore power. I want to upgrade to maybe a 125 amp alternator so I can recharge within a reasonable time. Any suggestions on what to look for or problems to avoid? Would this be a simple "pull-off-the-old & plug-in-the-new" operation? I think the current generation of alternators has internal regulators. Does anyone know if they are three-stage regulators?? Thanks to all.
Congratulations on the new boat. We have owned a 2005 Hunter 38 since 2006. Still love the boat.
We manage about 6 days off the dock / shore power and still have the stock 60 amp alternator. We typically anchor out and move most days, so even if we are sailing there will be some motoring out of and into anchorages. We do not have solar or wind charging.
If you do decide to go with a bigger alternator you should be certain that it is compatible with the alternator sensor cable. On our boats the Yanmar tach reads pulses from the alternator. If you change to a Balmar alternator you may need to have the tach re calibrated.... and I'm really not sure how complicated that is. To avoid this worry I purchased the optional 80 amp Yanmar alternator. Have yet to install it as we cope fine as we are. Nice to have as a spare. I think the Electromax alternators might work. I looked at a bracket to mount a second alternator on the starboard side of the engine but there is not the clearance needed in the engine compartment.
We have 4x 6v Trojan T105 batteries in addition to the 12v engine starter. They all fit in the battery compartment under the floor. This gives us about 450 amp hrs of house battery. The boat has a solenoid that parallels the house and engine batteries when the engine ignition circuit is energized and isolates them when the engine is off. The Promariner shore power charger has outputs to both engine and starter batteries. When we do go into port for the night I really want all the output from the charger going to the house battery. There is little in the way of amp hours consumer starting the Yanmar so starter battery is always close to 100% charged. What I did was move both of the charger output leads to the house battery I also move the charge wire from the alternator to the house battery side and installed a Xantrex digital echo charger to take power from the house battery side and trickle charge the starter battery as needed. There are dip switches on the Promariner charger that need to be set for the size of your battery bank. Can't remember the exact details but the manual should be available online.
We are very careful about what we use power wise. Have installed LEDs, try Marinebeam.com, the fluorescent lights are actually quite efficient also. We run the fridge 24/7 which when it's hot out is our biggest power consumption. We keep beverages in the freezer which is turned to it's warmest setting to run as a fridge. We only run it when the engine is running or when an shore power. If it's kept full stays cold / cool fairly well. The car radio type stereo and the Bose system and TV run off the inverter are both power hogs. You will want to change to some sort of LED anchor light.
There is a great iPad app called boat battery that you can use to inventory battery bank size and consumption. I also recommend Boat Owners Illustrated Electrical Handbook by Wing.
Hope this helps. Best wishes with your new boat.
