Thinking about installing a 2000watt Power Inverter to run a 1000W (1350W @
120vac consumed) microwave oven and to heat my hot water tank 1200W @
120vac not at the same time.

Or to use a 2KW portable generator.

When heating the water, I estimate that the run time is about 20 minutes to
achieve max temp.

I'm wondering if my house batteries could handle the additional load of an
inverter.

My boat has a 300HP outboard with 60-70 Amp alternator (i cannot increase or
change the alternator)

help is neeed for an old "Duffer"

"Duffer2" wrote in
:

Thinking about installing a 2000watt Power Inverter to run a 1000W
(1350W @ 120vac consumed) microwave oven and to heat my hot water
tank 1200W @ 120vac not at the same time.


Well..........

1200 watts divided by 12V (just to keep it simple) equals 100 amps, if the
inverter were 100% efficient, which it's not, but close enough.

100 amps X 12V for 20 minutes, not seconds like starting a diesel, is
probably way enough to warp the hell out of the house battery plates,
wouldn't you say? I would....they have little cooling for long hard pulls,
even the wetcells will get really hot.

One good battery explosion should just about convince you this is NOT a
good idea unless you have a battery rated for 100 amps for most of its
discharge time, which it's not. (Look under the seat of an electric fork
lift truck at what will. You probably won't want to float it.)

Actually, the fork lift batteries aren't a very good example, either. They
get the current down to a safe level by running 24 or 48 or 96 volts with
lots of cells in series to higher voltage traction motors. The Toyota
Prius, for instance, takes this notion even further putting so many cells
in series to get the current down low they run 400VDC or something like
that.

Nothing's funnier than watching a boater with a new, $4000, 4KW inverter
walking down the dock with an electric heater in his hand and a big smile
on his face.

The microwave works good for a couple of minutes, though, on an inverter.

So, you need a generator to do the job at a reasonable weight.

If it's just 1500 watts, this one will work:
http://www.hondapowerequipment.com/M...elName=eu2000i
It's a very quiet 2KW inverter running off a 1 cyl, computer controlled gas
engine whos actual engine speed has nothing to do with making 60 Hz. The
alternator in them looks like your outboard motor's high frequency stator
coils inside the magnet-encrusted engine flywheel. You can't hurt it like
a regular genset, either. If you overload or short it, its computer simply
shuts off the load and drops the engine to idle until you shut it off and
restart the engine after pulling the load off it. It will stand a short
overload over its rated output, warning you by turning the output light
from green to yellow to red, when it shuts it down. At only 46 pounds,
it's very portable and easy to store....

I have two of them, the EU1000i, the little 1KW brother to the 2KW. But, I
needed more power for my stepvan electronics shop so I got this one:
http://www.hondapowerequipment.com/M...lName=eu3000is
the big brother to the 2KW suitcase.

There is a BIG difference between the plastic suitcase gensets and the
3000is, however. The two little gensets have tiny, compact, FAST TURNING
little engines that, I predict, will wear out quite quickly at your 1350
watt load, working hard to pull it. The EU3000is, on the other hand, has a
much BIGGER, stouter, SLOWER TURNING and QUIETER engine with a much lower
running note. It's just larger, as you can see at 134 pounds. It also has
a MUCH larger STEEL fuel tank that will pull two 8000 Btu window air
conditioners and my little bar fridge and soldering equipment for over 8
hours on ONE tank that's REALLY easy to fill through the HUGE, strainered
gas cap made of STEEL, not plastic. The whole case is steel, not plastic.
The EU3000is is the finest genset I ever owned at any price, even the
diesel ones. One neighbor asked if that was my air conditioner outside
unit running...it's THAT quiet! Electric start comes from a separate
internal AGM lead acid battery built right into the case under the control
panel. Your boat's 30A shore cable plugs right into its twist-lock 30A
connector. It also puts out 12A from a completely separate winding to
charge your boat batteries while its running....12V at 12A charging only.

Because all of these gensets are a really nice, rugged inverter, the
engines have an Econo mode, switch selectable. I've never figured out why
they'd want to switch it to full speed...?? Pulling a 1500W electric
heater and a 1200W calrod hot plate with both thermostats switching these
big loads on and off don't wiggle an AC voltmeter (not included) monitoring
its output...the 3000is. Very save for computers and electronics.

The 3000is turns 1200 RPM in Econo mode until the total load is over about
1950 watts. That's SLOWER by 1/3 a big 4-pole 60 Hz commercial alternator-
direct genset. I don't know how long it will last. Mine only has about
2200 hours on it, estimated, and uses no oil at all. I change the oil at
around 100 hours, about every other week. It only holds a little more than
a quart and that's real easy from a little door on the opposite end from
the control panel. It has a drain plug and a filler with dipstick. It
also has Oil Alert and will shut itself down if it's low on oil. No oil,
it won't even start. It has a recoil manual starter to pull, but mine is
mounted against the back door of the van. Open petcock, pull choke
(manual) and turn key works every time, even UNDER THE TWO AIR CONDITIONERS
AND FRIDGE compressors coming on all at once!

It's a helluva great genset.

PLEASE INSTALL A CARBON MONOXIDE ALARM IN YOUR CABIN IF YOU GET A
GENSET....thanks.

On Mon, 3 Jul 2006 20:39:07 -0700, "Duffer2"
wrote:

Thinking about installing a 2000watt Power Inverter to run a 1000W (1350W @
120vac consumed) microwave oven and to heat my hot water tank 1200W @
120vac not at the same time.

Or to use a 2KW portable generator.

When heating the water, I estimate that the run time is about 20 minutes to
achieve max temp.

I'm wondering if my house batteries could handle the additional load of an
inverter.

My boat has a 300HP outboard with 60-70 Amp alternator (i cannot increase or
change the alternator)

help is neeed for an old "Duffer"


You need to consider the size of your house batteries plus another
important item.

Considering inefficiences, you're talking about using maybe 40 amp
hours to heat the water. A 4D (183 Amp hours and 130 pounds) ) or 8D
(225 Amp hours and 160 pounds) gel cell would probably be adequate.
You would need to run the engine almost twice as long as you run the
microwave to recharge.

The other item is that unless you spring for some really big bucks,
inverters do not put out a real sine wave, and microwave ovens seem to
be sensitive to that. Power output drops off, things overheat.

By the way, we burned up a coffee grinder and a power tool battery
charger using the inverter.

Our seagoing Winnebago has about 1000 Amp hours of house batteries and
we don't run the microwave on the inverter more than a minute or two.

For the Microwave, an inverter and a couple of T105, or L16 batteries
would be just fine. Your existing batteries may or may not be large
enough. Microwaves use a lot of power when 'on', but their on cycle
is typically not very long. So overall the total power draw is not
that great. For heating water though, not too likely... Heating
uses a lot of energy for a rather long period of time and containing
that muck energy in batteries is just not too practical.

Not knowing your boat or needs, there are a few options for heating
water: As you have an outboard, hooking into the engine cooling loop
is not an option for you. For dishes, sponge bath: Just use the
stove or microwave. Same for cooking. There are also instant
propane water heaters available, again not sure if one would work for
you or not and there is some controversy about their safety.

And then there is the idea of a small portable generator. Might be a
good solution for your situation, get a good quite one, takes little
room. Or, perhaps both! Use the Inverter to run the Microwave when
you want, then run the Generator once a day to recharge the batteries
and make hot water.

-al-



On Mon, 3 Jul 2006 20:39:07 -0700, "Duffer2"
wrote:

Thinking about installing a 2000watt Power Inverter to run a 1000W (1350W @
120vac consumed) microwave oven and to heat my hot water tank 1200W @
120vac not at the same time.

Or to use a 2KW portable generator.

When heating the water, I estimate that the run time is about 20 minutes to
achieve max temp.

I'm wondering if my house batteries could handle the additional load of an
inverter.

My boat has a 300HP outboard with 60-70 Amp alternator (i cannot increase or
change the alternator)

help is neeed for an old "Duffer"

Dick Locke wrote in
news
gel cell would probably be adequate.


AAAAAAAAAAAAAAAAACK! 100A off a gelcell for 30 minutes?!!

BOOOOM!

No cooling!

Melt it!!

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACK!!

Al Thomason wrote in
:

For heating water though

One wonders why we don't see the obvious solution to this hot water
problem more often....for free.....
http://tinyurl.com/sxuql

Australia has lots of water bladder websites. I suppose the simplest
solution is too simple for us Americans used to advanced technology they
don't have on the Outback.

http://www.fabricsolutions.com.au/liquid_bladders.htm

We are sold these rugged inflatable dingys and rafts made of nylon
materials that can easily withstand more pressure than your 12V water
pump can generate. So why can't we have a 6 gallon, flat black little
bladder that hangs off the stern with two black hoses, inlet bottom and
outlet top that pumps itself up and sits there in the FREE sunshine,
saving gallons of fuel by getting so hot you can't hold your hand on it
all day?? Make it with ears like dingy oarlocks to tie it down to a
wasted deck or even over the stern under the nav light like a big fender.
Sailboats have a big, wasted deck space on the centerline, under the
swinging boom, where an even bigger flat bladder heater would nearly boil
water all day, giving lots of free hot water, while keeping the sun off
the cabin roof.

Boaters are used to compromises, like taking showers when conditions
permit. Sailors will put up with a lot to NOT have to crank that noisy
diesel just to get hot water. This solution is totally quiet, uses no
energy from house batteries or fuel tanks, except to run the pump they
were already going to have to.

Win-Win?

A big ol' Navy fuel bladder made of heavy, flat black neoprene rubber
makes a HUGE hot water heater! Fresh water washdown? No, HOT water
washdown!...(c;

Another plus for the flat bladder heater on top of the main cabin of a
sailboat would be it puts the cabin IN THE SHADE, under the bladder! No
crazy-looking canvas awning would be necessary! The cabin would be
"water cooled" until the tank got hot...A thin layer of foam pad under
the bladder would insulate the "tank" and keep the cabin even cooler!

Of course, boat manufacturers COULD build us a little flat tank as wide
and long as the cabin top, about 3" deep, right INTO the cabin's black
fiberglass top. It would be permanently plumbed to the hot water pipage.

Another stupid idea like the Coleman RV air conditioner.....(c;

Larry wrote:
Al Thomason wrote in
:

For heating water though

One wonders why we don't see the obvious solution to this hot water
problem more often....for free.....
http://tinyurl.com/sxuql

Australia has lots of water bladder websites. I suppose the simplest
solution is too simple for us Americans used to advanced technology they
don't have on the Outback.

http://www.fabricsolutions.com.au/liquid_bladders.htm

We are sold these rugged inflatable dingys and rafts made of nylon
materials that can easily withstand more pressure than your 12V water
pump can generate. So why can't we have a 6 gallon, flat black little
bladder that hangs off the stern with two black hoses, inlet bottom and
outlet top that pumps itself up and sits there in the FREE sunshine,
saving gallons of fuel by getting so hot you can't hold your hand on it
all day??

Well, maybe in Georgia it will work, us Europeans will get luke warm
water for 99% of the time. Oops, I mean -- it will stay *COLD* !

Admittedly, it is 30 degrees Celsius right now where I am typing this,
but that's not what we usually get. And with this steaming tropical
weather, hot water is not high on our priority list :-)

--
Kees

On Tue, 04 Jul 2006 14:31:51 -0400, Larry wrote:

Dick Locke wrote in
news
gel cell would probably be adequate.


AAAAAAAAAAAAAAAAACK! 100A off a gelcell for 30 minutes?!!

BOOOOM!

No cooling!

Melt it!!

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACK!!

Hmmm, maybe I've overlooked something...heating of the battery should
be 100 amps times the internal resistance. I don't have a clue what
that is. Educate me!

Mika wrote:
On Tue, 04 Jul 2006 22:43:41 +0200, Kees Verruijt
wrote:


pump can generate. So why can't we have a 6 gallon, flat black little
bladder that hangs off the stern with two black hoses, inlet bottom and
outlet top that pumps itself up and sits there in the FREE sunshine,
saving gallons of fuel by getting so hot you can't hold your hand on it
all day??
Well, maybe in Georgia it will work, us Europeans will get luke warm
water for 99% of the time. Oops, I mean -- it will stay *COLD* !

Not hopeless, though. Have used them in Finland couple of times and I
tell you water can get real warm if you leave the black water bag in
sunshine for whole day. It has more to do with black plastic
absorbing sunshine than outdoor temperature.


Sun? Where?

You can always tell when people are from an area where the sun doesn't
shine normally: they'll be the ones that are tanned from catching those
precious rare rays; people from sunny places stay out of it at all costs...

And yes, I have severe sunburn from last weekend's very rare combination
of sunshine with warm weather :-) here in the Netherlands.

I saw on the news that it was nice in Finland as well?

--
Kees

Kees Verruijt wrote:

Admittedly, it is 30 degrees Celsius right now where I am typing this,
but that's not what we usually get. And with this steaming tropical
weather, hot water is not high on our priority list :-)

30C is "steaming tropical weather"? We've hit 45C already, and summer is
just starting! Probably won't hit 50C this year (although we have a few
times). Enjoy the lovely winter you're having :=)

As for solar heating, I don't know what the suns' intensity is at your
latitude (when you see the sun, that is), but in the summer here (34°
latitude) it can be as high as 375 BTU/ft^2/hr (10WattHr/M^2/hr) with
the absorbing surface normal to the sunlight. So there's energy to be had.

Keith Hughes
(reclining in sunny Arizona)