100 amp alternator. Does that mean it charges 100 amps in an

[sailingdolphin]

?

So if I have 4 6v = 220 amps each and a 12v system I really have 440 amps of which I can probably use only 300 before I need to recharge.

Does that mean with a 100 amp alternator it would take 3 hours to recharge? And at what RPM?

I am looking at the batteryshack alternator.

[sailingdolphin]

#71 no name yet. We have owned 2 months.

[Stu Jackson]

You're Almost There

440 amp hours in house bank.

Useful capacity is only about 35% of the 440, or 154 amp hours when on the hook.  Not a problem on shorepower.

This is because:

1.  don't discharge more than 50% (although you could, a bit more)

2.   the last 15% takes forever to recharge from an alternator

Your energy budget will tell you how many days that will last you.  That is, add up all the loads times how many hours per day you use them, which will give you needed amp hours per day.  (BTW, with your 440 AH bank, you will do JUST FINE!)

A 100 amp alternator will put out 100 amps at a certain speed.  Jeff's right about the output curve.  Plus, if you're anchored, you won't be running the engine at max speed, only about 1500 rpm.

If motoring you'll get more out of the alternator.

So, say with inefficiencies and slow motoring or just at high idle when anchored, you get 75 amps out of the alternator.

If you've used up all 154 amp hours, it'd take you two hours to put it back.

The concept is to MINIMIZE draw on the house bank, by turning off lights, insulating (or turning off) the fridge, etc.  If you run the fridge 24 hours, you'll use up 60 amp hours (5 amps average draw - or less - including run cycle times 24 hours).  If you turn it off at night (since it isn't opened) and maybe use a space blanket insulator inside, you almost cut your daily amp hour use in half.

Do the Energy Budget, then go from there.

Stu

[PAUL T.]

You might want to consider a Honda 2000 watt generator if you spend much time away from shore power. The generator will run your battery charger, heat your hot water in 15 minutes or less, run your fridge on 110 while it's on and any other 110 uses you may have. All this with never running your engine!!!!. The generator only ways 46 pounds and is extremly quiet and fuel efficient. Its like having an ace in the hole, because you always have a means to start your engine if you accidently drain your batteries to much.  Just a thought PAUL......

[sailingdolphin]

Paul,
where do you store your generator?

How do you have it hooked up to run your hot water heater?

I was going to try and run my hotwater heater with the batteries. I don't think thats going to work especially with an 11 gallon hot water heater. If I did I would use all my amps.  I would need additional batteries.

How do most people run there hot water heater away from shore?

[Ken Juul]

With the hot water heater loop, running the engine to charge the batteries also heats up the hot water.  Just need to time your battery charging to coincide with your hot water needs.

[SteveLyle]

D&D,

Your hot water heater is powered by either 110v shore power, or the engine coolant.  When you're off shore power and you want hot water, start your engine up.  The engine coolant circulates through a heat exchanger in your hot water heater.  Voila.

Steve

[sailingdolphin]

That takes a long time and is very loud.

Has anyone ever looked into a propane generator and installing it in the aft lazarette.

Would that be safer than gasoline?

Has anybody ever done this? Does anyone have any ideas on how to handle the exhauset?

[sailingdolphin]

I found a propane 3400 watt generator measuring 20x17x16.75 with an exhaust kit and remote control on off swith.

I need to go measure the lazarette space. I am thinking with the exhaust kit I can run it thru one of my clam shells.  Any thoughts?

#71 no name yet.

[jentine]

I have had a Batteryshack alternator for about three years and have only used it to charge the batteries at anchor on one occasion.  I have found that it will replenish the batteries from a state of discharge in several hours at 1200 rpm.  The owner of the Batteryshack told me that it is designed to produce full power at 1000 rpm.  
I don't know why anyone wants to put a generator on their boat.  Introduction of a vibration with the accompaning noise is not my idea of relaxation.  If you look up to the sky,  you will see the largest generator you have ever seen.  It is quiet, yellow and free.  All you need to do is provide the means to collect the free energy.  A couple of solar panels and a regulator and good-by to noisy, smelly, expensive generators.
I can't understand why anyone has any charger other than solar panels (unless you live on the dark side of the moon). A good solar panel will last longer than the boat. I have been using solar panels to charge four 6v, house bank for many years without a single failure. My batteries charge all week with the refrigeration running (also on solar) here in New England with no difficulties. The cost of a couple of solar panels and a controller is less than a good quality battery charger.
Jim Kane

[PAUL T.]

Donna and Doug..... I store my generator under the dinnete to the right of the mast, empty of fuel of course. I keep the fuel in a safty can secured on deck. Solar panels have there place but can't heat your water in 10 to 15 minutes,or start your engine in an emergency. especialy if the sun is not out!!!!! As far as noise and vibration go, You must hear a HONDA 2000 watt generator to believe how quiet they are and there is no vibration felt below if I place the gen. just in front of the mast. Also I can turn on the gen. and leave the boat for several hours and come back to charged batteries. You can't leave your boat with the engine running! The gen. has several safety features that will shut it down if there is a problem. As far as solar panels go, who wants his boat to look like a space satelite with panels hanging all over it!! The propane gen. you speak of probably costs a small fortune plus the hassel of installation and where are all those prpane tanks going to go? Just Some Thoughts....PAUL

[PAUL T.]

DONNA and DOUG I forgot to mention, all you have to do is run a shortened shore power cord between the generator and the shore power inlet. This will heat your water and anything else you have powered by 110 volts... PAUL

[Stu Jackson]

THE BEAUTY OF SAILING

is that there ar different strokes for different folks.

I'm personally looking forward to a multi-engined, multi-generating, fuel cell driven, sail powered space vehicle myself, and know, when the time comes, that the folks on this message board and the C34 community will be the best in helping everyone out with technical issues.

KEEP UP THE GOOD WORK.

Best,

Stu

[PLKennedy]

Solar panels or wind generator:

Liking the quiet of the wind, I have been considering either a solar panel(s) or a wind generator here in New England.  The solar panel option seems a good idea, but where can it be mounted where it won't be stepped on?  The wind generator also seems good, but where would it be mounted considering the bimini?

I would really appreciate any advice, since this topic, and brain surgery are foreign ot me.

My concern is cruising for a week or two, keeping the fridge on, and minimizing the cabin lights, moving with the engine/sail about every three days.  I have the two batteries that "Snow Goose" came with new in 2001; no other backup.  I run the engine on both batteries, and when done with the engine, alternate batteries each day.

Peter

[karista]

Peter
I have both, a 120 watt Kyocero panel and a Air Marine wind generator.
The panel is mounted on the cross bar of the Kato davits, the Air Marine wind generator is mounted on a mounting pole kit at the port aft transom corner. I have a total enclosure bimini and there is no problem of fitting the wind generator pole and support poles.
Now if you would ask me if I would do this again, the answer would be NO. The wind generator output is neglible below 15 knots, and here in SW Florida the winds are generally light. The solar panel would be the preferred choice, however one panel only will not be enough to maintain your batteries with the refrig. on all the time. The toal cost for both was over $2000 including regulator and mounting kits etc. For about half the cost you can buy the Honda 2000 generator and never have to worry about whether you have wind or sun.
Bernd Mueller