Inverter vs Genset

I have had both aboard my Egg Harbor. Inverter is good for nights on the hook when you can have the hatches open, or running over for a quick lunch or dinner - keeps the fridge running, but you may want to turn off the ice maker. Genny is needed for all the heavy work like a/c during the day when anchored out.

I tended to use my genny in all situations, except at night

Agree - repair or replace the generator. A suitable size/battery capacity inverter ( like the 3 kW) system, preferably with a dedicated battery bank, is great to have on board - will do much of your day to day stuff (lighting, entertainment, fan ventilation, battery charging) but the list of exceptions (heat and air conditioning, water heating) and gray areas (cooking, refrigeration, bait pumps, etc.) is pretty long, especially for a boat size of yours. Quality inverter systems correctly interconnected are easy to operate, reliable, and low maintenance, but the downside is available battery capacity. A 12 kW inverter system is possible, but a battery set to give you a practical run time for the large loads would be either outrageously expensive or very heavy/impractical for a planing boat. Shore power capacity for quick recharging could be an issue.

REPLACE. Do not fix the generator. You need a generator.

Meh, Northern Lights are really good pieces of equipment. With the motor seized from salt water intrusion, likely source would be the heat exchanger, but a total tear down of the engine would be required, so the end result is as good as new, in my opinion. Salt water into the engine doesn't bother your power generation side of the unit. But you'll want that tested as well while you have taken the unit apart.

"Easiest" solution is either rebuild or replace exactly what you have. Don't go larger unless your calculations show that you require to do so. But if you're considering an inverter as your sole source, sounds like bigger is not necessary. So, explore the cost of new like kind as well as the cost of a rebuild.

I've been that route with a 58' Hatteras YF, which is the same boat as the OP's except has a cockpit. Ironically with a 16 kw Northern Lights. We had to pull the starboard pilot house window to get it in. It is such a ******* to get the generator in and out of that boat to either rebuild or replace it (same with the generator end), it's best to replace with new as the cost was only a tiny bit more than rebuilding it.

A lot of these older generators you simply cannot get parts for. On a trip, it cost an owner close to $150 to have an alternator bracket on a 1984 NL that snapped welded in Charleston, S.C. and a day's pay Captain and mate, because the $9.87 bracket was nowhere to be found in Northern Lights entire system and NL quoted a 4 week lead time. It's that way for many brands of old generators. Can't find ANY parts for the old ONAN's Hatteras installed in these boats.

We didn't have the height with the NL to make the turn to go down the steps. I didn't install it, the boat yard did, I just watched.

Look, If the heat exchanger is the access portal for salt water, there's a range that the seizure is mild. Lugger is a sleeved engine. The injectors are looking at you, right in the face. Hell, pull the injectors and pour in some Marvelous. Let it sit for 24 hours, lay a heating pad onto the head, and come back the next day and try to turn her over again. If she moves she can be torn down where she sits and rebuilt in a couple of days. If that all works out, you can rebuild the genny AND add an inverter for the price of a new genny.

If the owner isn't a wrench guy, I'm sure there's help close by that can lead him to a point where more information can provide a more certain path forward.

Yes, and you can disconnect the generator from the motor to lighten the load and shrink the dimensions. That galley can quickly become a pretty nice workshop, too.

When rtrafford said repair the genny and add an inverter/charger - got me to thinking. Check out a 12 kW inverter/charger and a small capacity lithium technology dedicated battery set (easy to find room for). My inverter/charger (Outback brand - brand used by Nordhavn) has automatic shore power switching and generator control/interfacing/relay (boat never had a generator). What I like is automatic operation - all I do is plug/unplug the shore power - the inverter/charger takes care of the rest. When in inverter mode (disconnected from shore power) the inverter/charger looks at the battery set state of charge and would automatically start the generator to take the load and recharge the battery set, and then shut down the generator when finished/unloaded/recharged if I had a generator.

For you, this would give a completely automatic system, and use the generator only when needed. IMHO, this would not be an overly complicated installation task - all the pieces are standard stuff.

I understand that the experienced folks posting here have had some problems with inverter/charger reliability and battery lifetimes - true - the marine environment, etc. There have been some major brands that have not been too good, but I read of good service from Magnum, and I have had the Outback 3 kW inverter and the Crown lead acid batteries in service for 7 years. The last year annual load test was 90% of the first. I maintain the batteries (twelve 8 volt golf cart batteries 165AH each) properly, and the recharge current is set a bit lower than maximum. Also, the inverter/charger monitors battery temperature when charging and shuts off at 55% state of charge. In my system, both inverter/charger and the batteries are well removed from the engine space heat/vibration/moisture, which is not always possible.

The way we operate, not usually more than 4-6 hours away from shore power or on the hook maximum of 2 nights (no AC), this works great for us, however, if this boat had had a busted generator when we bought it, I would have repaired or replaced it then.

Not to put this the wrong way, but do you know how many hours you can run a 12 kw generator at 1/2 a gallon per hour? 12 KW inverter bank? What are you going to charge it with?

Thanks for the questions. 1/2 gallon per hour seems like a reasonable fuel burn for a 12 kW generator, so I figure the run hours would be determined by the fuel quantity. To further clarify what I suggested: Note that for both generators and inverters, the kW rating applies to the total nominal power in kilowatts (the load), measured at a specific time - not over a time. kW measured over a time, kWh, is actually a measurement of (total) energy, not power. For example, a resistive (electric heater) load of 1.5 kW which is 1500 watts (120 volts x 12.5 amps = 1500 watts) operating for 1 hour consumes 1.5 kWh of energy(1.5kW x 1h = 1.5kWh).

My suggestion above called for a 12 kW inverter/charger sized to match the generator kW. The actual battery bank attached would be small. It would operate the system at 12kW load only for, say, 10-15 minutes, but for much of the time (no ac), the typical load is way below 12 kW, so the small battery bank would provide enough energy to operate for a number of hours. Disconnected from shore power/on inverter operation, the small bank begins to discharge, slowly (no ac) or more quickly (ac is on). When the battery bank voltage/state of charge (SOC) decreases to the inverter/charger's generator start set point, the inverter charger starts the generator to pick up the load and recharge the bank to 100%. When the bank is back at 100% SOC (the generator is powering the inverter's charger at this point) and/or the big load has gone away, the inverter shuts down/disconnects the generator, and the cycle repeats until the shore power is reconnected. When shore power is back, the inverter's charger tops off the bank, and shore power carries the loads. Most any modern quality inverter/charger can operate this way right out of the box - folks who live off-grid power their homes in a similar manner.

On the boat, the generator would have to be operated with control set up for remote start only.

Thanks. I hope I made it clearer.