Generator vs Batteries

[DaveK]

After having owned Hattini (1985 43' Motor Yacht 3208 Cats) for 6 weeks And am slowly learning the systems and getting much more comfortable with close quarters maneuvering. First I apologize if the answers to the following questions should be obvious but I have not been able to get my head wrapped around operating Hattini without the generator. The boat currently has 2 8D batteries for each engine. The port bank also powers all 12 volt accessories and lights. The starboard bank also function as starting batteries for the generator. There is a power alarm at the helm that will go off anytime the A/C power is not functioning, EG switching from shore power to generator or switching back.

I would like to know that I can operate the boat without the generator running. I realize the refrigerator and ice maker will not function but have thought I could run the generator for an hour or so every four or five hours. I am trying to 1. Cut down on a bit of fuel usage and 2. Eliminate unnecessary hours on the generator itself.

Am I worrying about something needlessly? Is it possible to disable the alarm for situations where no A/C power will be used?

Thanks

 

[Pascal]

It depends on how you use the boat.... If you don't spend days and days on the hook then don't worry about the hours on the generator. It also depends on the weather.... I m all for saving a few bucks but it means sweating because you're not running the AC,l then it s not fun. Diesel gensets are meant to be run and run and run.. And can easily run over 10k hours

That said, if you spend a lot of time on the hook especially in winter when you may not need the AC, then yes running off th batteries can save money, hours and also bring you some nice quiet time. In some case adding an inverter and a few extra batteries to powwer the fridge, etc... Will pay for itself in a few months

 

[MikeP]

Back when these boats were designed, it was common for cruising boats to start the genny upon leaving the dock and not shut it off until the boat was back at the dock or hooked to elec power at a transient marina. So from that aspect, I wouldn't worry at all about running the genny. We knew some folks in Stamford CT with a 58 LRC that essentially ran the genny for months at a time. They left CT with the genny running and never turned it off for their entire cruise/stay in FL and back.

Of course, fuel was a lot cheaper in those days and running the generator on our 53MY will burn about 23 gallons of fuel in 24 hours and, at around 3.50 a gallon, that adds up pretty fast.

OTOH, I do not believe in "camping" on the boat. If the ACs need to be running for us to be comfortable, than the genny's running and we don't hesitate to do that.

But an inverter is a good way to power things like the fridge, microwave, whatever without running the genny. As Pascal pointed out, it all depends on how you use the boat.

 

[jim rosenthal]

What they said, and I would suggest that if you can, you add a separate starting battery for the generator, which should recharge from the generators DC output (most generators can be set up to charge their own starting battery) and also make sure that it is tied in to a 12vdc charger just like the other battery banks. If I've read this correctly, you have two banks now. A separate bank to start the genset may get you out of trouble if somehow all those 8Ds end up dead. Any good marine electrician should be able to hook you up with this.

Generators thrive on load and should be run with a moderate load at least. They last longer and work better that way.

 

[SEVEN]

No one has addressed the alarm. Don't disconnect it just tape the button on the helm where the red light is to shut off the noise but not the light. How many hours does the genny have on her?

 

[DaveK]

No one has addressed the alarm. Don't disconnect it just tape the button on the helm where the red light is to shut off the noise but not the light. How many hours does the genny have on her?

She has approximately 800 hours at this time, the mains are right at 1100.

 

[Dan Mapes]

The boat has an AC monitor switch in the middle of the AC panel. Turn it off if you don't what to deal with the alarm. I do. BTW if you still have the origrinal AC frige, and you want to replace it go with an AC/DC unit and you are good to go.
We unloaded the Uline Combi unit on the aft deck for a NovaKool frige that fits in that spot just fine. It's quiet and runs on AC/DC.
The down side to flipping the main frige for a dual voltage unit is you will have to remove the center front window to get the new one in.
We also installed a ProSine 3KW sine wave inverter. I pulled the batter cables over to the port side bank from stbd, split the port bank between the engines and that gave me two 8Ds to drive the inverter which is located behind the paneling in the salon.

Now the only time we run the gen is to recharge the batteries while out and about, or, to cool off the boat after a long run in the heat. Usually I will start it up an hour or so before docking so the boat has a chance to cool off before we go down below.

 

[bobk]

Dave,

Hattini is wired like my 1981 48MY. In my case, that AC power alarm only sounds if I were running with generator on and the generator stopped unintentionally. If I do not start it, or if it is running and I turn it off on purpose, the alarm does not sound.

Regarding running on the generator, as others have advised, it depends on how you are using the boat. I cruise long hours and anchor a lot, so among the first upgrades was an inverter to keep the fridges running and TV playing when on the hook. The inverter is powered from 6 golf cart batteries (8 would have been better, but we get 12+ hours operation comfortably from it).

BTW, don't forget if you are running the generator, keep a load on it, not just the refrigerator, and give it a cool down period before shut down. On my 12.5KW Westerbeke, the manual calls for 2-5 minutes operation with out load before shut down.

Bobk

 

[thoward]

We start the gene before we leave dock and do not turn off until we return. It is an Onan so it is a bit obnoxious but in Fla we need AC. I wouldn't worry about the hours and the yearly fuel cost is probably the cheapest part of owning the boat....

 

[magnawake]

X3 on the inverter. Best 5K I've ever spent. 6V golf cart batteries do the trick. I do anchor out as much as we can. From Fall to spring anchoring in a secluded area with no noise and dolphins playing around while you grill steaks on the sundeck is priceless. OTOH, in the summer anchoring on the inland parts of the ICW with the bugs and heat will make you run the genset all night you cant put a price on that either. Like others have said its all how you run the boat. My freezer will start defrosting pretty fast with the genset running. The inverter was my answer.

 

[capttonyf]

As far as the AC Alarm going off. Anytime you lose AC Power that alarm on the Hatteras Helm Panel is going to go off. But that being said, I've never seen one that doesn't have a Silence Button right next to the Test Button that you push to see if alarms are working. We just had the fuel pump go out on our Onan and the AC alarm went off. I just hit the Silence Button and it didn't make a sound for remaining 3 hours before we got back to the dock.

Tony

 

[DaveK]

To all,

Thanks so much for the input. For the time being it looks like the generator will continue to be run as it is very hot here. I am planning to replace the 8Ds with group 24s in the near future so while doing that project an inverter will probably become part of the equation.

Dave

 

[gbharrington]

Just asking, but why would you want to replace 8Ds with 24s?

 

[DaveK]

I want to get rid of the 8Ds and group 24s are the first thing I've looked at. When I actually start that project I will research further as there may be better options.

 

[gbharrington]

I have looked long and hard at replacing the 8Ds, and IMO the best solution is to replace 2 8Ds with 3 6V golf cart batteries. The performance/value/life equation is superior and most* 8D battery boxes will accept 3 golf cart batteries.

* In my 77 43DC the Hatteras built battery boxes which are located outboard of the engines are 1/2" too short, necessitating aftermarket battery boxes. I believe that you have a different set up.

 

[Steve Mannshardt]

I installed a new 16 kW Northern Lights unit with sound shield in March of 2014. Hr meter as of today is 914 hrs. It's the first engine started on this boat and the last one shut down. Frankly it provides better and cleaner power than most marinas. When it does die it will get replaced with the same thing. I have an inverter yet frankly think it's a waste of fuel dragging it around.

 

[jim rosenthal]

Steve, you are likely to be retired before that generator dies. There was a verified account a few years ago of a 6.5 kW NL set that was on the deck of a fishing boat in Prince William Sound, I think it was, or the Gulf of Alaska, which had twenty thousand hours on it, and no overhaul. They only stopped it to change oil and filters, do routine servicing. It wasn't even in a full enclosure, although they had a little metal roof over it, I think. NL sets are TOUGH.

 

[jim rosenthal]

I don't know about golf cart batteries, but a Hatteras 8D case WILL fit three Group 24s set crossways. Of course, you end up with a lot of cabling that you don't have with 8D in the same space- more expense, more potential failure points, etc etc. But they WILL fit.

Under the heading of "things I wish I had not done", many years ago, when I was even stupider than I am now, I took one of the fiberglass 8D cases out of my Hatteras- the one in front of the starboard engine. I can't even recall WHY I did it, except that the AC strainer is there now- maybe I wanted to change the AC plumbing? What I DO remember is how hard it was to get it out. I ended up taking it out with a Sawzall. It was bonded to the stringers etc- all 36Cs were built with the large battery cases, even gas engine boats like mine was at the time.

Well, I wish it were still there. They are much better than any other battery cases I have ever seen. Typical Hatteras quality, built like a brick outhouse.

My boat has three group 24s in the remaining (port) 8D case- two in parallel are the engine starting bank, and the other starts the genset. Under the aft deck, in front of the live well, are two 4D cases which hold the house bank. There is still a paralleling switch. This system has worked well for me for years, but if I had been smarter and not cut up the original stbd case, I'd have an 8D house bank ahead of the stbd engine. Live and learn.

 

[tellico]

stupid question of the day ... how does one "replace 2 8Ds with 3 6V golf cart batteries" as per above?

I replaced 2 8d's, with 4 GC's, strapped together in pairs to make 2 12v, but what do you do with 3?

What am I missing?

 

[Colwyn D]

I have the inverter arrangement for the fridge and quiet nights at anchorage scenario but with the expense and complication of the inverter and it's batteries I also see the benefits of the original generator only set up. I did lose the first inverter which added to the cost and the replacement inverter did require a completely different install.
On balance I'm happy with the inverter but we cruise and anchor out a lot. If we tended to use marinas then I'd rather have the genny only and not have the constant concern of battery state and energy consumption. I think the cost differential would be small after install costs and several battery replacements with the inverter.

I run a pair of group 31's for starting both engines and a small house bank of four 31's. All these are installed in the lazarette and the useless plastic battery boxes I had have been replaced with glassfibre boxes. First just the starboard side but now have a longer one alongside it holding the house bank.