Two Generators, needed?

[dar636]

Hello all,

I have two aux gensets, a 8kw Onan in the lazzarette and a 15kw Westerbeke in the gen room under the galley. Both work, get used for specific reasons, both are getting to be vintage and while I understand that having a two aux power sources has its advantages operationally, there are just as many negatives in my opinion when it comes to maintenance and the space devoted to each, the Onan in particular.

So my questions are: How many of you have dual gensets and wouldn't have it any other way (and why), and how many have removed one or both to upgrade to newer better units?

I'd really like to have my full lazzerette space and a newer real quiet 20kw under the galley.

 

[Pascal]

Depends on where you are and how you use the boats. SoFl and Bahamas where air con is important, having redundancy is really nice. That said these old hats have excellent ventilation so loosing air con isn’t as critical as it is on a modern boat

Your profile says your in the PNW where air con isn’t critical. I’d probably remove the smaller genset and keep the 15kw Beke. They are nice reliable units. 15 is probably more than you need. That s what I have on my 53...

Then I would replace the second genset with a 4kw inverter and a few extra batteries along with a higher output alternator to charge that bank from an engine if needed. You won’t run air con but at least you ll keep refrigeration, microwave, lights, TVs and small cooking appliances running should you loose the genset.

 

[dar636]

I do have a 3200kw Outback inverter/charger along with the original (I think) Lewco 40A/32v charger. The Lewco is set up as a backup to charge the 32v house bank, when selected. It is normally off. The Outback charges or maintains the two engine 32v banks as needed, as well as the house bank when dockside or with genset power. It switches to an inverter when running the main alternators.

As you say we don't need AC often, and then not for but a few hours. I still have the 4 zone reverse cycle systems, though I generally use prior installed small 110 wall units in the staterooms, salon and galley for heat. Heat and AC is available with dockside power or with the gensets only.

The inverter runs all the systems you describe; refer, lights, and several outlets, etc.

 

[SKYCHENEY]

Replaced my 20kw Ohno with a 15kw Norpro several years ago. I see no need for more than that.

Although I like redundancy, I think a newer genset and an inverter is sufficient as you limit the gen hours with inverter.


Also depends how often you cruise to remote destinations and how long you stay there. A second genset could be a lifesaver if you are far away from parts and service.

 

[Boatsb]

Newer generators are less vulnerable to under loading but still need to get sized properly. If you find the 15k able to run everything you need on a daily basis that's great. Keep in mind full ac needs and cooking may make the 20 or so kw necessary.

As to inverters. They're great if setup and deployed well. In most of my customers vessels the inverter is used along with the generator when on the hook and if ac is not needed used more.

32 volts is a bad idea for an inverter if you want to get fully integrated into the systems. Theres not good battery choices, few charger and inverter choices and no modern battery technologies. LiFePo batteries are far more efficient, lower maintenance, longer lives and lighter. Yes they cost more up front but if you can cut charging time by 4 to 6 hours a day and not have sulphation issues.

Add a second alternator to the main engine, set up a dedicated bank and integrate it properly into the vessels electrical system.

I design systems to meet customers specific needs not to be an easy install or to use existing items. It's been very successful since I became a full line distributor (not just dealer) for victron.

 

[Bob Bradley]

Sky,
Just a tip on the Norpro. If you aren't doing so already, clip a nice hot incandescent lightbulb next to the genny end over the winter. My boat has never (and I mean NEVER) had any water intrusion problem, yet my Norpro 9kw gen end toasted itself 2 years ago from corrosion after about 6 seasons in the boat. I'm in CT, so it does have significant temp swings throughout the offseason. The winter following the replacement, I checked out the genny one weekend and it was absolutely soaked with condensation. Ever since, I've clipped a light next to it for the winter. That seems to have solved the issue.

 

[SEVEN]

My two were replaced with one Onan 15KW and I don’t see any reason for having two. The 15 seems to run everything we need.

 

[SKYCHENEY]

Sky,
Just a tip on the Norpro. If you aren't doing so already, clip a nice hot incandescent lightbulb next to the genny end over the winter. My boat has never (and I mean NEVER) had any water intrusion problem, yet my Norpro 9kw gen end toasted itself 2 years ago from corrosion after about 6 seasons in the boat. I'm in CT, so it does have significant temp swings throughout the offseason. The winter following the replacement, I checked out the genny one weekend and it was absolutely soaked with condensation. Ever since, I've clipped a light next to it for the winter. That seems to have solved the issue.

Thanks, but mine has a Marathon generator end on it. I doubt it will be a problem. I also store in a heated building in the winter.

Sorry to hear you had a problem.

 

[Briankinley2004]

I have one 23KW M&L Marine Leader generator. So far it has been fine but only has 350 hours on it. A back up would be nice but having space is nice as well. I know it is going to go out one day at sea as there are too many electrical components for it not to. A/C is almost a must and also my electronics run off my 12volt battery which is charged by the generator and/or a 110V powered charger that runs off generator. I am not too keen on that but thinking about getting some kind of invertor or something to power that circuit if genny fails

 

[Pascal]

15kw is about 60/62 amps... that’s 20% more than a 50amp shore power...

 

[Leland]

This is an interesting thread for me. The new-to-me boat purchased in January has two - a 20KW and a 12KW. From the hours, the 12KW gets the most use. Being in the Pacific Northwest, AC is seldom used. In 15yrs on our Grandbanks we used the AC maybe a dozen times. The Genset was primarily a battery charger. So the question has been in the back of my mind: do I really need two generators? It sounds like the consensus is; not really. Then, the question is do I really want to remove one? The benefits would be less weight and more space. Maybe sell the 20KW...? Hmmm...

Bob

 

[racclarkson@gmail.com]

This is an interesting thread for me. The new-to-me boat purchased in January has two - a 20KW and a 12KW. From the hours, the 12KW gets the most use. Being in the Pacific Northwest, AC is seldom used. In 15yrs on our Grandbanks we used the AC maybe a dozen times. The Genset was primarily a battery charger. So the question has been in the back of my mind: do I really need two generators? It sounds like the consensus is; not really. Then, the question is do I really want to remove one? The benefits would be less weight and more space. Maybe sell the 20KW...? Hmmm...

Bob

Think you might ever sell the boat to someone who might take it where they need AC? Sell the 12KW.

 

[oceanjake]

My boat has a lot of AC reliant items. Refrigeration, A/C, etc. Also bridge and electronics power (12v) is provided by a dedicated 12v bank maintained by a battery charger rather than engine charging. For that reason I think a redundant generator is a must on my boat if planning any long range trips. It really depends on the setup of each boat.

 

[piripucha]

I have the same boat 58YF. Originally it came with your set up, an 8KW aft, and a 15 KW in front under the galley. Both where Onan. The 8 KW was so noisy ( circa 1978) that my father diched it after 2 years and installed a 20 Kw onan that lasted 20 years. Both were replaced by Northern lights 16 KW and we could not be happier. Taking into account that we are in the tropics we need the redundancy of a full set up, specially because the water maker, and de AC pull a lot of amps. If you need back up go with the same make. that way you could cannibalize parts in case of an emergency.

 

[oldawg]

If you spend a lot of time on the hook, using the smaller genset may save a bit on fuel if used during non-peak times (like at night). It will also extend the interval between oil changes.

 

[dar636]

I have the same boat 58YF. Originally it came with your set up, an 8KW aft, and a 15 KW in front under the galley. Both where Onan. The 8 KW was so noisy ( circa 1978) that my father diched it after 2 years and installed a 20 Kw onan that lasted 20 years. Both were replaced by Northern lights 16 KW and we could not be happier. Taking into account that we are in the tropics we need the redundancy of a full set up, specially because the water maker, and de AC pull a lot of amps. If you need back up go with the same make. that way you could cannibalize parts in case of an emergency.

Hi - so you have two 16kw's now? or one?

 

[piripucha]

I have two (2)- Both are NL , one is a M844W and the othe is a M844. We install them at diferent times.

 

[nautibake]

My boat has a lot of AC reliant items. Refrigeration, A/C, etc. Also bridge and electronics power (12v) is provided by a dedicated 12v bank maintained by a battery charger rather than engine charging. For that reason I think a redundant generator is a must on my boat if planning any long range trips. It really depends on the setup of each boat.

We have a single 21 KW GenSet, a dedicated 12V bank for electronics that is charged by 12V charger and / or when underway by starboard engine via Newmar 32 to 12V reduction. Separate 3000W inverter 24V bank runs refrigeration ice makers, coffeemaker, salon TV and select outlets for charging cell phones, etc. While on the hook we run the GenSet 2 hours in the morning and 2 hours in the evening as has been mentioned by OPs on this site many times. Works great for us.

Having said all that, I still dream of adding a 2nd GenSet to (maybe 7Kw) dedicated to the Seakeeper gyro’s, which are always running if we are underway. Okay, and a cockpit. Still dreaming...