Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-14-2020, 10:31 AM   #21
Senior Member
 
fgarriso's Avatar
 
City: Pueblo West, Co
Vessel Name: GOTCHA
Vessel Model: DeFever 59-B PH
Join Date: Jun 2019
Posts: 438
The only way to size a generator is to add up all of the loads and add 10%.

It is just simple math!
__________________
Advertisement

__________________
Captain F. Lee - R.P.E.
USCG 200 ton Master
fgarriso is offline   Reply With Quote
Old 04-14-2020, 10:48 AM   #22
Technical Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,185
Quote:
Originally Posted by fgarriso View Post
The only way to size a generator is to add up all of the loads and add 10%.

It is just simple math!
Not necessarily good advice. If you add up everything and add 10%, you may end up with a really big machine that ends up spending most of its time running at 20-30% load 90% of the time and that is not good for the engines.

Best to size it modestly and tolerate some load management.

If you absolutely do not want to manage load, then size it as you suggest. Just understand there are downsides to doing that.

This applies especially to a smaller boat (like OP's 32). Not so much to a large boat, as that will usually have plenty of load and the physical size and weight of the machine is a non-issue.
__________________

Ski in NC is offline   Reply With Quote
Old 04-14-2020, 02:53 PM   #23
Senior Member
 
City: Three Oaks, TN
Vessel Name: Pipe Dream
Vessel Model: Silverton 42C
Join Date: Apr 2020
Posts: 147
FWIW, My 1986 41' Hatteras Came from the factory with a 50A, 240V shore power service which was just about right for two A/C's and all electric appliances. Unfortunately the engineers at Hatteras assumed that no one away from the dock would actually drop an anchor and cook! She came equipped with an 8kw (30A, 240V) genset. Then, to make matters worse, I installed a 240V watermaker. Life seemed to be a constant rerun of the "Green Acres" episode where Eva Gabor had to carefully add the numbers on her electrical cords in the kitchen to keep from blowing fuses.

When we finally declared our 8.5kw Onan close enough to death to be rid of it, we upgraded to a 12kw and life was good again! Last I heard, the Onan's three cylinder Kubota was still merrily providing power for an Amish woodshop.

For me, the moral of the story is that too much power isn't nearly as much trouble as too little.
PPandE is offline   Reply With Quote
Old 04-14-2020, 02:59 PM   #24
TF Site Team
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 11,856
Quote:
Originally Posted by Unclematt View Post
What size diesel generator is needed to power a 32' trawler with reverse cycle heat / ac, electric stove, lights and other basics while anchored? Has anyone heard of Nexgen they make a 4K genset. I am working on figuring out how much the boat will cost above sale price before making an offer. Thanks Unclematt
What shore power connections do you have? Is it a single 30 amp or dual 30 amp connections?
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you aren’t one, there is no explanation possible.
Comodave is online now   Reply With Quote
Old 04-14-2020, 04:28 PM   #25
Guru
 
syjos's Avatar


 
City: Gig Harbor
Vessel Name: Sandpiper
Vessel Model: Bluewater 40 Pilothouse Trawler
Join Date: Nov 2012
Posts: 2,284
The 5.5 Kw generator is perfect in the winter running electric heaters and hot water tank.

In the summer at anchor, the 120 VAC holding plate freezer compressor and the battery charger are the only loads after the 15 amp hot water tank reaches temp. The compressor uses about 5 amps and charger consumption declines as the battery gets charged but starts at around 20 amps when the batteries are down 50%.

So in order to keep the generator loaded after the water heater turns off, I have to run an electric heate outside the boat. When I had the 4.5 Kw generator, did not need to run a heater but sometimes had to manage loads.

Reason to correctly size the generator.
syjos is offline   Reply With Quote
Old 04-20-2020, 01:01 PM   #26
Member
 
gknoepfler's Avatar
 
City: New Orleans
Join Date: Mar 2017
Posts: 17
I have an’06 IG 32 with a 5kw split genny. I have to manage the loads to keep from tripping. I wish I had a 6-7 kw. Below is a load test I did with most of my heavy draw stuff:

Sea Neff 110V Amp Loads

House Bank
• Water Heater - 12 Amps
• Microwave Oven - 10.5 Amps
• Kuerig Coffee - 11.7 Amps
• Hair Dryer - 13 Amps

A/C Bank
• A/C Water Pump - 2 Amps
• Both Air Handlers - 3 Amps
• Forward A/C Compressor - 5 Amps
• Salon A/C Compressor - 7 Amps
• Peak Amperage with both A/C's - 31 Amps

Hope this helps.
gknoepfler is offline   Reply With Quote
Old 04-20-2020, 01:40 PM   #27
Senior Member
 
City: green cove springs
Vessel Name: GEM
Vessel Model: Mainship Pilot 34
Join Date: Nov 2016
Posts: 124
hi,

we anchor out 95% of the time on our ms 34 pilot. it is all electric with a 12k ac. we have a 3.5kw nextgen and have never had a problem as long as you managed your loads. mornings we do battery charge + coffee. when coffee is over i run water heater + charger. afternoons will run ac + charger. we grill a lot but if we use the stove top there is no ac or wh.
__________________
John
GEM 2003 Mainship P34
Duetto is offline   Reply With Quote
Old 04-20-2020, 01:52 PM   #28
Guru
 
Bryant's Avatar
 
City: Fleming Island, Fl
Vessel Name: Sakura Perdido
Vessel Model: Grand Banks 36 Classic
Join Date: Jul 2016
Posts: 543
Generator size

Quote:
Originally Posted by Unclematt View Post
What size diesel generator is needed to power a 32' trawler with reverse cycle heat / ac, electric stove, lights and other basics while anchored? Has anyone heard of Nexgen they make a 4K genset. I am working on figuring out how much the boat will cost above sale price before making an offer. Thanks Unclematt
I have a 36’ trawler. Two AC units, microwave, electric oven, small fridge, water heater, various outlets with “stuff” constantly plugged in. I have a 9.5kw

Adding a generator or even changing one can wind up becoming a large and very expensive project. If you are buying a boat that will need that, I suggest you have a professional look at this boat and give you an estimate. Even if you have to pay for this info, I think you will be glad you did and surprised at the cost.
Bryant is offline   Reply With Quote
Old 04-20-2020, 02:42 PM   #29
Veteran Member
 
tomdove's Avatar
 
City: Annapolis MD
Vessel Name: Snowbird
Vessel Model: Grand Banks 32
Join Date: Aug 2015
Posts: 41
My Grand Banks 32 has its original Westerbeke 4.5 kW genset and it seems like the right size for the boat. She has reverse-cycle A/C, microwave and a gas stove. The Westerbeke is suffering from a worn-out water jacket that is no longer available and I'm dreading replacing this otherwise perfect genset.

I only use the generator when I'm running the A/C at anchor or have some other specific need for it, like running power tools or recharging the house battery bank. The prior 3 owners must have done the same, because it has very low hours even though this was a Florida boat for most of its life.
tomdove is offline   Reply With Quote
Old 04-20-2020, 03:23 PM   #30
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,797
Northern Lights 8 kw is what I had in my GB32 with an electric galley.

The make doesn’t matter, cost and maintenance availability are more important. The most important is to determine the expected loading and get on sized such that it has to work a bit. Too large and it won’t have enough load and it will fail prematurely. Whatever vendor you decide on should be able to advise.
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 04-20-2020, 03:24 PM   #31
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,797
“Worn out water jacket?”

What? Tell us more?
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 04-20-2020, 04:04 PM   #32
Guru
 
FoxtrotCharlie's Avatar
 
City: Mississippi
Vessel Name: ADAGIO
Vessel Model: CHB Present 42 Sundeck
Join Date: Jul 2014
Posts: 855
When we bought our boat it had a non-working 15K 4 cyl Westerbeke - took up half of the ER. Purchase price reflected. Boat originally had elec stove - replaced long ago with propane. Did a load calculation for two 16k a/c, water heater, frig, ice maker, microwave, coffee maker....Installed a 2017 9k Kohler in sound box and have been very pleased while at anchor in 95 degree Southern heat Did not want to have to fool around with load management.
FoxtrotCharlie is offline   Reply With Quote
Old 04-20-2020, 05:35 PM   #33
Senior Member
 
fgarriso's Avatar
 
City: Pueblo West, Co
Vessel Name: GOTCHA
Vessel Model: DeFever 59-B PH
Join Date: Jun 2019
Posts: 438




__________________
Captain F. Lee - R.P.E.
USCG 200 ton Master
fgarriso is offline   Reply With Quote
Old 04-20-2020, 07:01 PM   #34
Guru
 
High Wire's Avatar
 
City: Cape May, NJ and Englewood, FL
Vessel Name: Irish Lady
Vessel Model: Monk 36
Join Date: Dec 2007
Posts: 3,918
Quote:
Originally Posted by gknoepfler View Post
I have an’06 IG 32 with a 5kw split genny. I have to manage the loads to keep from tripping. I wish I had a 6-7 kw. Below is a load test I did with most of my heavy draw stuff:

Sea Neff 110V Amp Loads

House Bank
• Water Heater - 12 Amps
• Microwave Oven - 10.5 Amps
• Kuerig Coffee - 11.7 Amps
• Hair Dryer - 13 Amps

A/C Bank
• A/C Water Pump - 2 Amps
• Both Air Handlers - 3 Amps
• Forward A/C Compressor - 5 Amps
• Salon A/C Compressor - 7 Amps
• Peak Amperage with both A/C's - 31 Amps

Hope this helps.
Split - Does this mean your genny is setup 125/250 with 2.5 kw available per side? Or is it 125 VAC only feeding 2 panels?
__________________
Archie
Irish Lady
1984 Monk 36 Hull #46
Currently in Cape May NJ
High Wire is offline   Reply With Quote
Old 04-20-2020, 09:31 PM   #35
Member
 
gknoepfler's Avatar
 
City: New Orleans
Join Date: Mar 2017
Posts: 17
5kw produces about 42amps. I have a 2 pole circuit breaker on the genny, 20 amp each side.
So, I can’t run both ac's under genny, too much amps. Have to manage other heavy load stuff also,
gknoepfler is offline   Reply With Quote
Old 04-21-2020, 02:19 AM   #36
Senior Member
 
Nickair's Avatar
 
City: Offshore
Join Date: Jan 2015
Posts: 257
Quote:
Originally Posted by HiDHo View Post
You might check out Dometic Smart Start unit. My boat has two 16,000 btu heat pumps run by a single 5 kw NL generator. The Smart Start takes 65% out of load start spikes. No problems with generator overloads and my generatorj load is probable 75% or more making for a happy generator.
These smart start, or similar units can reduce the needed load coverage. Fellas that I have heard used them said the same, they work good. Although it is one more thing.

The size genny, as said is relative to the load you wish to manage.
__________________
Simplicity, is the ultimate sophistication.
Leonardo Da Vinci
Nickair is offline   Reply With Quote
Old 04-21-2020, 02:46 AM   #37
Senior Member
 
greatpapabear's Avatar
 
City: Guernsey, Channel islands
Vessel Name: Play d'eau
Vessel Model: Fleming 55
Join Date: Jun 2008
Posts: 304
Quote:
Originally Posted by Unclematt View Post
What size diesel generator is needed to power a 32' trawler with reverse cycle heat / ac, electric stove, lights and other basics while anchored? Has anyone heard of Nexgen they make a 4K genset. I am working on figuring out how much the boat will cost above sale price before making an offer. Thanks Unclematt
Hi. I'd add two key considerations.

1) Whatever max load you think you'll need, add a margin. Why? You may buy more kit. You might use your electric kettle for a cuppa but won't want to turn off the a/c while the kettle boils.

2) Make sure you have a genny which auto-regulates your 60Hz frequency. Why? Some items you may have on board are very frequency critical. For example, a modern hob for the galley (I think you call them burners).

GPB
__________________
GPB
Follow our great adventures: www.playdeau.com
greatpapabear is offline   Reply With Quote
Old 04-21-2020, 03:00 AM   #38
Veteran Member
 
Obelikx's Avatar
 
City: Amsterdam
Vessel Name: Obelikx
Vessel Model: De Klerk Kotter
Join Date: May 2012
Posts: 29
Quote:
Originally Posted by Ski in NC View Post
Not necessarily good advice. If you add up everything and add 10%, you may end up with a really big machine that ends up spending most of its time running at 20-30% load 90% of the time and that is not good for the engines.

Best to size it modestly and tolerate some load management.

If you absolutely do not want to manage load, then size it as you suggest. Just understand there are downsides to doing that.

This applies especially to a smaller boat (like OP's 32). Not so much to a large boat, as that will usually have plenty of load and the physical size and weight of the machine is a non-issue.
You might also consider a different approach: a smaller genny that is supported by a lager inverter;
The disadvantage of a larger generator that is sized to meet your peak demands is that 99% of the time it will work at only a small percentage of its total power; not good for the diesel engine which will probably die prematurely and also not very efficient in terms of fuel usage.
If you size the generator to meet your basic continuous needs (like the AC running 24 h and whatever continuous loads you might have) at around 70% of generator power and you add a large inverter with a top-up function to meet your peak demands (like when cooking while running AC) it is more cost effective. The inverter will top up the power using the house bank for the peak demands (which will normally only be a few minutes, like until the water boils etc) and after the peak, the small power reserve of the generator will be used to reload the house bank. During the whole time the diesel will work in a very efficient range (also good for its live expectancy).
The overall costs of the system (small genny & larger inverter) are similar to a larger genny and a small inverter; the follow up costs are lower.

When my old 25 kw generator died 8 years ago, I replaced it with a small 10 kw panda and added an inverter/charger that can deliver a synchronized 20+A/230V in addition to either the shore power (which is between 4 and most of the time 15 A/230V in the local marinas) or the generator.
In the old situation, I had to start the generator even when having shore power for cooking larger meals (with several pots on the stove and the oven running); in that situation my average energy consumption on the A-meter in the kitchen was around 6-8 A but the peak sometimes around 30 A/230V 50Hz – only for a few minutes but too much for the max 15 A shore power; now the inverter kicks in during the peak moments and my total generator time is down to the time at anchor where I run the genny like 2 h a day (during dinner cooking and to refill the house bank) and the inverter powers the 230 V appliances for the rest of the time. I safe around 100 h of generator time a year compared to the previous situation. The overall investment in a smaller genny plus larger inverter are almost the same as a larger generator, however the running coast are much lower and I freed up a lot of space in the engine room. I hindsight, I would take an even larger inverter or combine two of them, just for peace of mind because I had a few situations when running AC plus cooking plus washing machine where I had to watch the ampere meter again in order not to overload the system.
Obelikx is offline   Reply With Quote
Old 04-21-2020, 06:24 AM   #39
Technical Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,185
Quote:
Originally Posted by gknoepfler View Post
5kw produces about 42amps. I have a 2 pole circuit breaker on the genny, 20 amp each side.
So, I can’t run both ac's under genny, too much amps. Have to manage other heavy load stuff also,
You may want to look at how the gennie breaker and the rest of the boat is wired. If a 120v boat both poles of the output breaker should be tied together giving a total of 40A. If a 240V boat, load is not balanced between legs if it trips.

Needs a closer look if tripping with the two ac's on.
Ski in NC is offline   Reply With Quote
Old 04-21-2020, 07:30 AM   #40
Veteran Member
 
City: Stuart
Vessel Name: Passport
Vessel Model: Mainship Sedan Bridge
Join Date: Dec 2016
Posts: 42
Last year I replaced the 9kw Kohler on our 40' Mainship with a 4.5kw Phasor, and couldn't be happier. Much quieter, and less weight to haul around.
It will run any three of the seven major devices, two a/c's, hwh, electric range, microwave, hairdryer, inverter/charger charging depleted batteries at the same time without straining.
__________________

bykpjfk is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 01:19 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×