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labatt 10-13-2008 01:57 AM

Help costing a generator and lots of generator questions...
We're looking at adding a small (4.5kw-6kw) generator to our Passport 40 (to add Air Conditioning). Northern Lights and NextGen seem to be the ones we're being steered towards. I've read mixed reviews on Panda's - many people say they've had no issue with them, many have said they have had significant issues.

Anyway, what goes into installing a generator? I'm assuming that, in addition to the cost of the generator itself, you have to add: Panel (on/off, temp, pressure, etc.), through hull for cooling water, fuel filter, exhaust separator (unless you want to listen to it splash all night), engine mounts, electrical connection to AC panel, some sort of source switch (battery, shore power, generator), soundproofing. Do AC generators come with DC alternators for battery charging? Or do you wire the AC side to your existing charger? Am I missing any parts?

Assuming I'm going to have someone else install the unit, how much should I expect to budget for pieces and parts and for installation? Right now I'm just trying to determine affordability.


Omatako 10-13-2008 04:42 AM


Originally Posted by labatt (Post 383332)
Anyway, what goes into installing a generator? I'm assuming that, in addition to the cost of the generator itself, you have to add: Panel (on/off, temp, pressure, etc.), through hull for cooling water, fuel filter, exhaust separator (unless you want to listen to it splash all night), engine mounts, electrical connection to AC panel, some sort of source switch (battery, shore power, generator), soundproofing.

I'm also busy investigating fitting a genset and for my sins have "inherited" a Fischer Panda - whether that turns out to be wise or not will be discovered soon enough . . . .

In the mean-time here are some things that I've learned, they may answer some of your questions.
  • I'm going to T off from the thru-hull that feeds my main engine raw water so that I don't have to make another hole in my boat. The chances that you'll run the two together seem unlikely and obviates the need for a second strainer as well.
  • The exhaust is another issue and will need, I think, to be a new installation with it's own water lift and silencer, the good thing is that the hole for the exit can (and in my case will) be above the waterline.
  • The FP has it's own alternator and it is intended to have it's own start battery. I suppose this is intelligent because the genset will be most handy when you're out of amps on the house bank. I don't know how the other makers handle that.
  • Once again speaking for the FP, the box in which the genset is mounted is apparently virtually soundproof in it's own right. I'm hoping this is so and looking at the structure of the box, I reckon it will be. Again, can't speak for the others.
  • From what I've seen in the FP manual, the installation requires raw water, exhaust, a place to mount the remote control panel and electricity to start (external battery). It also requires an external fuel pump to supply diesel to the unit and an anti-syphon loop for the raw water. I believe the installation which I'll do myself is going to be easy, the toughest part being making space for it (hope I'm not deluding myself)
  • My one is not AC so can't comment on that.
I'm not clear on what you mean by an "exhaust separator". Can you elaborate please.

Zanshin 10-13-2008 06:28 AM

I have the smallest FP installed. The housing provides soundproofing, but is by no means soundproof and in my case the genset is mounted aft in the steering enclosure and when it runs it can still be noticed throughout the boat; if I close the doors to the aft cabin(s) then the noise level goes way down, and if I run the air conditioning then it is no longer noticeable. The exhaust system exit above the waterline is a dry one to minimize exhaust noise and that works well.

I use my generator about 10-15 minutes a day - long enough to warm up the espresso machine and make 2 cups and I use that time to give the batteries a partial recharge so that the generator is working under a load. I also will recharge the handheld transmitter, notebook and other rechargeable battery powered stuff as well.

The Fischer Panda generates AC output only, this then goes to the battery charger (which results in further loss), but this is better than getting a DC only generator since that would have to go through an inverter in order to provide AC for air conditioning.

I've been researching the stirling engine WhisperGen, which is quiet but produces only DC current (and not much of it, at that) and warm water and heating. It uses less then 500ml diesel per hour, though. Since I'm in the tropics, the hot water is of little interest to me (the main engine produces sufficient hot water from just motoring out of an anchorage). If I were in colder waters then the WhisperGen might have been an option.

The plumbing and electrics involved in putting a generator in are pretty involved, even though I love to putter around I think I would choose a professional to do this work - plus it wouldn't invalidate the warranty on a GenSet.

dshafer45 10-15-2008 05:29 PM

$8,000 for a 5kw Northern Lights (check Internet for low cost supplier), plus at least another $3000 for related systems and installation. Very complicated...make sure it's done right. My Tartan 4600 is on a mooring year-around, so gen set is absolutely essential, although only use it infrequently for AC/reverse cycle heat.

btrayfors 10-15-2008 08:13 PM

You'll need at least a 5K generator if you're gonna run A/C on that Passport 40.

Figure at a minimum $7-8K for the generator, and about $2,500-3,000 for professional installation. Recommend you have the gen dealer install it, get a sound shield, and pay attention to servicing needs (location of water filter and water pump impeller, fuel solenoid, oil and filter change, brushes, etc.).

I've been happy with my 3.5KW NextGen. It will run one of my A/Cs OK, but I'd really like to have more room, though.

Remember not to spec it too close. A 5KW genset won't provide 5KW continuously. As they heat up, output is reduced by 20-30%. Other things (like power factor of load, poor fuel, etc.) can also make them deliver less power than you'd think.


labatt 10-15-2008 08:19 PM

Thanks for the info... I thought the install costs and such would be significantly more, so this is great news! With regards to AC units, we think we can get away with a single 16k BTU unit connected to the same vent system our Webasto is connected to. The 5k-6k units are what we think we can fit in the space beneath our cockpit.

camaraderie 10-15-2008 09:58 PM you size the generator for the AC remember to factor in the AC water pumps, and higher amp requirements at startup. Our 8.5kw ran a 16k + 12K without a peep...I'm not sure what kind of leeway a 5kw unit will give you on a 16+5 so perhaps the AC mfr. can spec that out for you including start up and the pumps.

btrayfors 10-15-2008 10:46 PM

Another thought: you're in the frigid north, where heating is a necessity in winter. Even though you already have a Webasto diesel heating system, you may want to consider the following.

Many/most marine A/C units with heat use a heat exchanger system, drawing heat from the water. These work OK as long as the water isn't too cold, but require moving water (pumps) continuously.

After considerable investigation, a few years ago I chose to install the same units used by the USCG and Canadian Coast Guard...those provided by Flagship Marine:
Marine Air Conditioning Systems - water, air and keel cooled.

These have the option of using a large electric heating coil instead of a heat exchanger. They work beautifully. The coils draw 2,000 watts, and just one of these keeps my 42-footer warm on most winter days. I have two units (16,500 and 12,000 BTU).

A friend who lives aboard a similar sized boat also chose the Flagship units, and has been very happy.

And, their pricing is very good and the packages include just about everything necessary for an install....all quality stuff, not cheapo junk.

I also have an Espar D5L system which by itself can keep the boat toasty in any weather. However, the electric heating is clean, safe, very convenient. On very cold nights (like <10F) I sometimes set the Espar thermometer about 5-10 degrees below the Flagship heater thermometer, so in case of power failure or other reason the Espar will kick in if necessary.

Just a thought....


labatt 10-15-2008 11:07 PM

Bill - Thanks for the info. We're actually putting the generator and AC unit in since we're heading south to Annapolis and then FL/Bahamas/etc. at the end of November, so our heater will be somewhat extraneous for the moment :). I overheat very easily, so the AC unit has made it to the top of our list.

T37SOLARE 10-16-2008 12:14 AM

I'm not very familliar with the Northern Lights, but have you looked at the Onan gensets? I've heard nothing but good stuff about them.

Just a suggestion for another option....

Good on you for making the decision to go for it, I'm on your heals, I just have to wait a couple more years.....

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