AC and Generators

[DougSea]

I was just reading rangoons post (welcome to the board by the way!) and it made me start thinking about add ons to my 28TE. I started looking at the Cruisairs AC site on the web and their small (can be powered by an inverter) AC unit. It's only 3500BTUs but I don't have a lot of need for heavy AC here in Connecticut so this unit might do the trick, remove humidity and drop the temp to a good sleeping level, especially since I expect to spend more time 'on the hook' than in marinas.

So my questions to the board; Anyone out there with AC in a 28TE? Size? Brand? Are you happy with it? etc? And the same questions with generators. I know the larger guys have them but I'm specificly interested in anyone with 28TEs. Engine box models in particular. Looking forward to hearing about your boats.

Doug

BTW - still owe you guys the story of my trip up from Maryland, I'll get to it soon!

[Mariner]

Well, don't fall into your category as I've got a 36' Express Tralwer, but I thought I'd offer my own two cents.

We have two AC units in our boat, which can only be run by the 5kw generator. They're supposedly not supposed to be run off shorepower unless you have a 50amp hookup, but those are unheard of here, so I just run it on the 30amp anyway. No problems yet. The load doesn't ever even approach 30 amps.

I would be cautious with any unit that you can run off the inverter. Mainly just because you need to be sure that your batteries are up to the task. Make darn sure you've got your start battery thoroughly isolated and that your entire system from the batteries to the wires and the inverter itself, are up to the task. Do the math and get an idea of how long you'll be able to run it before your battery goes dead. I've found that our unit spikes when it first kicks on, but after that, the draw is reasonable. Also, if you plan to run it while underway, make sure that your alternator is putting out enough power to keep your batteries charged.

Another option is to just buy a unit that you will only use while connected to shorepower. Honestly, I can't imagine that we'll use ours much on the hook anyway. I just can't stand having the generator running.

I've actually found that since ours can be used for heat as well, we use them more in the winter for that, than we do for cooling in the summer. We also have a diesel heater which we use when underway or on the hook, but when sitting at the dock, the AC heats the cabin essentially for free (marinas don't usually charge based on consumption, just for the nightly hookup, which we'd use anyway). As a side note, I'd really like to add a red-dot style heater for use when underway which truly would heat the cabin for free.

[jcollins]

Doug,
I have a Crusair carry-on unit in my cabin. Haven't even tried it yet. Since we keep the boat at our shore shack, if we're there, we're in the house. Running a carry-on via the inverter wouldn't be a good idea. I don't think the battery would last the night. (Mariner is good with the electrical calculations) My intention is to purchase one of those 2k Honda portable generators. Guys around here leave them on the swim platform. The Honda is quiet and would have enough power to run the AC unit. I do have a 800 watt generator that I keep on board just in case. It has enough power for a small battery charger if I ever get stuck. I've only used it once it the last 5 or 6 years but I was happy I had it when I needed it.
As far as the BTU of my Crusair, I'll make a note of it when I get down to the boat. I'm sure it works fine for the small cabin of a 28.

[DougSea]

Thanks for the replies guys.

John - where do you store your generator? And where would you store the Honda which, while not really large, isn't 'tiny' either. And more than anything, where do you store the fuel? One of the things that attracted me to the Albin as my first inboard was the safety of the diesel engine and fuel. As attractive as the Honda option may be I just hate the idea of carrying gasoline.

I did look briefly into small diesel generators, $7000+ !!! Yikes!!

Still considering the 3500BTU AC unit and a big azz battery dedicated to it, Cruisair claims over 8 hours of runtime...that would be enough for me.

[Denis]

I have not done the calculations, but I can't for the life of me figure out how a battery would power AC on a boat. I have two deep cycle batteries just for the refrigerator and they really take a hit over the course of a night on the hook. Look at how small a refrigerator is compaired to the size of a cabin.
I use a 2kw Honda generator on my 28TE and it works just fine. I put it up front near the bow pulpit and run the cord back to the connection when I have it in use. I bought a cover for it so I can store it there when on the hook or mooring. It is much more quiet that way. I keep a gallon of gas on the deck behind the seat. I use it twice a day to charge the batteries and warm the hot water, about 30 minutes each.

[DougSea]

From Cruisair's website:

NEW! Zephyr Cuddy
This new low-profile 3500 BTU self-contained unit is made for boats too small for an onboard genset. It is powered by a user-provided inverter or shorepower. Not only can the boat owner enjoy the comforts of air conditioning, but also other AC-powered appliances away from dockside power.

If you go to the site (http://www.cruisair.com/self.html) there's a link to the PDF brochure on the unit. I've sent a note to them to get some pricing and additinal battery life info. Even if I did end up with a generator I like the idea of a unit small enough to run for short periods without the generator having to be pulled out and fired up.

Something to think about...along with a thousand other upgrade ideas!

[jcollins]

Thanks for the replies guys.

John - where do you store your generator? And where would you store the Honda which, while not really large, isn't 'tiny' either. And more than anything, where do you store the fuel? One of the things that attracted me to the Albin as my first inboard was the safety of the diesel engine and fuel. As attractive as the Honda option may be I just hate the idea of carrying gasoline.

I did look briefly into small diesel generators, $7000+ !!! Yikes!!

Still considering the 3500BTU AC unit and a big azz battery dedicated to it, Cruisair claims over 8 hours of runtime...that would be enough for me.

Doug,
See the pic below for carry-on storage.


I store the generator I have now under the flip-up step at the helm. I don't know the size of the Honda.

[Mariner]

Obviously our boat is a different animal, but just for grins the other day I decided to try running the AC off the inverter (which is powered by a dedicated bank of four golf cart batteries). There were only a couple pages of basic instructions that came with the boat. One of those was a warning to not run the AC off the inverter. Still, I looked at the wiring, and I looked at the load on the shroepower while running the ac and decided to give it a shot. First off, our boat has two AC units, one for the main salon, and one for the staterooms. Only one can be run on the inverter, the other one isn't even wired to be able to. After just a few minutes the voltage on the battery bank had dropped to 10 volts and I shut it off. Yes, it could get you by in a pinch, but you'd probably only get 10 or 15 minutes out of it.

That said, I don't see why with a big enough battery bank, and a powerfull enough inverter, you couldn't make it work. The issue is just whether or not it's more weight efficient to carry fuel and a generator.

[DougSea]

Hey Mariner, thanks for sharing the details of your 'experiment'. I'd be interested to know how big an AC unit you were running.

I'd still love to find someone who has the Cruisair unit, 3500 BTU's should be more than enough to cool off my forward cabin. Here's more from their web-site:

---
We recommend a separate set of batteries for the air conditioning.
Deep cycle AGM or Gel Cell batteries are the best for this application.
We have tested the following performance with a 1000 watt inverter of
good quality:
Two Group 31 batteries – 5 1/2 hours of run time
Three Group 27 (standard boat size) batteries – 8 1/2 hours of run time

A bit better than 10 minutes! Based on a quick 'back of the envelope' calculation an 8D House battery should run the system for 7 hours or so, that would get me through the hot part of the evening, just need to make sure my house and starting batteries are isolated (they're not now, much to my surprise)

Of course I'm also looking at the size of my alternator since that's how I'd be recharging, along with a solar pannel to keep things topped of while she sits on her mooring. The AC is a possible future project but the care and feeding of my batteries is very high on my priority project list!

[Mariner]

If you plan to run off the house battery, just remember that you will have additional loads (lights, etc..), that will reduce your run time. A truly dedicated battery makes the most sense.