The microwave goes overboard.

Use the stove for cooking.
When heating water, make extra and store in a thermos.

I'm still using my laptop for "TV".
No external display yet.

All lights converted to LED.



Remember you don't want to totally kill your batteries.

Adding another pair of batteries will of course double that and is the
less expensive route then LED lighting.

not so sure about that one...


Rick


--

Richard Lamb

On Thu, 14 Oct 2010 11:35:31 -0500, CaveLamb
wrote:

The microwave goes overboard.

Oh no, don't do that. How will you reheat the left overs, cook the
instant frozen dinners and warm up the coffee? The microwave also
makes a good bread box when not heating things and I understand some
people have used them to dry their wet cat (once).

In all seriousness, they are very efficient at quickly heating things,
and for you propane and alcohol users, provide an alternative way of
cooking if the fuel runs out.

Wayne.B wrote:
On Thu, 14 Oct 2010 11:35:31 -0500, CaveLamb
wrote:

The microwave goes overboard.

Oh no, don't do that. How will you reheat the left overs, cook the
instant frozen dinners and warm up the coffee? The microwave also
makes a good bread box when not heating things and I understand some
people have used them to dry their wet cat (once).

In all seriousness, they are very efficient at quickly heating things,
and for you propane and alcohol users, provide an alternative way of
cooking if the fuel runs out.


I think you got that last part backwards, Wayne.
The alcohol or propane will still work long after the batteries are dead.



--

Richard Lamb

On Thu, 14 Oct 2010 12:13:51 -0500, CaveLamb
wrote:

In all seriousness, they are very efficient at quickly heating things,
and for you propane and alcohol users, provide an alternative way of
cooking if the fuel runs out.


I think you got that last part backwards, Wayne.
The alcohol or propane will still work long after the batteries are dead.

I've been on boats that ran out of propane for various reasons, not
good for crew morale.

I view batteries as a renewable resource as long as the engine and
diesel fuel hold out. Our trawler is an "all electric" boat - no
stove fuel of any kind. I've come to appreciate that when I see
people schlepping various stove fuels in their dinghy or trying to
find the right adapter in a foreign country.

On Thu, 14 Oct 2010 13:35:58 -0400, Wayne.B
wrote:

On Thu, 14 Oct 2010 12:13:51 -0500, CaveLamb
wrote:

In all seriousness, they are very efficient at quickly heating things,
and for you propane and alcohol users, provide an alternative way of
cooking if the fuel runs out.


I think you got that last part backwards, Wayne.
The alcohol or propane will still work long after the batteries are dead.

I've been on boats that ran out of propane for various reasons, not
good for crew morale.

I view batteries as a renewable resource as long as the engine and
diesel fuel hold out. Our trawler is an "all electric" boat - no
stove fuel of any kind. I've come to appreciate that when I see
people schlepping various stove fuels in their dinghy or trying to
find the right adapter in a foreign country.

I think that there is a different mind set in the two types of boats.
Sail boat people all seem intent on saving electricity; trawler people
don't seem to give a hoot and have ice makers and all kinds of helpful
things.

I have a friend, has a 55 ft. ferro-cement ketch - 125 HP engine (and
a small gasoline gen set) and is forever saving electricity. He has a
separate inverter, sized for the usage, on every AC appliance in the
boat, LED lights that are too dim to read with, and is forever
worrying about amps. AND, he has an engine powered freezer and
refrigerator which he uses on trips....

I also know a motor boat guy that has all AC except for the radio and
nav lights. 150 HP engine (and no gen set :-)

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

On Thu, 14 Oct 2010 08:43:16 -0400, Wayne.B
wrote:

If you want normal life from your inverter batts it is important to
limit the discharge level to less than 50% (about 11.7 volts when
under load). The net result is that you need twice as many amp-hours
as your energy budget, perhaps more if your recharge time is limited.
It take quite a while to bring the charge level back to a full 100%
because the acceptance rate tapers off once you are above about 80%.
A good design point for A-H capacity is 3 times your energy budget.

Wayne, the 50% rule doesn't really apply to golf cart batteries. Back
in my electric car days there was a "trick" we used when we were
stupid and came to a stop from totally discharged batteries. Wait 10
to 20 minutes for the batteries to "self charge", then play
egg-on-accelerator and we'd get another mile or two. Wait and repeat.
Sometimes it took three or four of these cycles to get home.

Having said that, it's a good idea to limit to 20%, simply because
most inverters will shut down around that point.

A good point on taking a while to bring to a full charge. A lot of
folks think you can just pump in the Amps with a big alternator, but
it doesn't work that way in the real world.

A bit of golf cart battery advice. There are two battery manufacturers
in the USA, and they pretty much do the same thing. We bought the
same batteries from Sam's for $72 each as the local dealer had for
$160 each. By same I mean the same brand and model.

Re microwaves and coffee pots. It boils down to personal preference
and the boat systems. In our case we had enough solar so it was "free"
renewable energy as opposed to burning propane that we had to replace.

Rick

On 10/14/2010 3:24 AM, Rick Morel wrote:
On Wed, 13 Oct 2010 18:18:13 -0700, Stephen Trapani
wrote:

Well, occasional microwave, charge cell phones, morning and afternoon
coffee, lights, and hopefully a TV/dvr.

Kind of putting it all together...

I haven't seen the "brick" powered TV's in quite a while. Maybe at a
flea market or something?

The Golf Cart batteries are the best. Two in series should be fine for
what you want, but let's see.

Daily power, taking your "list" above out of order:

First, to determine the daily power requirements you have to take the
current draw, Amps, of each thing and multiply by the number of hours
used to get the Amp Hours per day of each. Remember, anything powered
by the inverter is going to be the 120VAC Watts divided by 10 for 12V
Amps.

We'll do that below, with best guesses.

Lights: I'm sure your talking 12V ones. The anchor light is the
biggie, with incandescent at about 1.5 Amps for 12 hrs.

[ 18 Amp Hours ]

LED would be about 2 Amp Hours, but cost more than a couple more
battereis.

Inside lighting. Varies, but say 2.5 Amps for 5 hours.

[ 12.5 Amp Hours ]

Same as above for LED inside lighting, but not as expensive.

Charging cell phone: Negligible if you have a 12V charger.

Coffee:

We had a 10-cup with thermos type carafe. It drew 75 Amps and ran for
5 minutes. Just to make it easy, let's say 6 minutes, 1/10 of an hour
or 7.5 Amp Hours per pot. Morning and afternoon then are

[ 15 Amp Hours ]

Microwave: We get a bit iffy here. Our 800 or 900 Watt one, I forget
which, drew about 95 Amps. That works out to about 1.6 Amp Hours per
minute of use ( 95 / 60 ). So you don't want to use it too much.

Let's say a couple meals reheated and a few cups of coffee and put it
at 15 minutes. 15 X 1.6 =

[ 24 Amp Hours ]


TV/DVD: Ours, using both was about 5 Amps as I recall. Figuring 4
hours in the evening and 1 hour of news in the morning, that's

[ 25 Amp Hours ]


Adding it all up, the total is:

[ 94.5 Amp Hours per day ]

So you're looking at basically 2 days with your batteries.

With LED anchor and inside lighting,

[ 68 Amp Hours per day ] Quite a difference.

Basically almost 3 days.

Remember you don't want to totally kill your batteries.

Adding another pair of batteries will of course double that and is the
less expensive route then LED lighting.

Hey, thanks Rick!

Just for jollies I looked at the back of my 42" home HDTV (plasma) and
it said 387watts, so do I have it right that since watts = amps/volts,
this TV will consume 387/120 = 3.2amps , so 3.2 amphours per hour?

Stephen

On Fri, 15 Oct 2010 08:19:56 -0500, Rick Morel
wrote:

Wayne, the 50% rule doesn't really apply to golf cart batteries. Back
in my electric car days there was a "trick" we used when we were
stupid and came to a stop from totally discharged batteries. Wait 10
to 20 minutes for the batteries to "self charge", then play
egg-on-accelerator and we'd get another mile or two. Wait and repeat.
Sometimes it took three or four of these cycles to get home.

Having said that, it's a good idea to limit to 20%, simply because
most inverters will shut down around that point.

I'm sure that it's possible to get away with an 80% discharge for some
period of time. I've seen some fairly convincing life cycle charts
however that seem to indicate greatly increased battery life at the
50% level as opposed to 80%. I like to baby our house batts as much
as possible given the expense and difficulty of replacing them.

See "Cycles vs Lifespan" at:

http://www.windsun.com/Batteries/Battery_FAQ.htm

http://img32.imageshack.us/img32/9595/batterydod.gif

(from site: http://www.mpoweruk.com/life.htm )

On Fri, 15 Oct 2010 07:44:48 -0700, Stephen Trapani
wrote:

Hey, thanks Rick!

Just for jollies I looked at the back of my 42" home HDTV (plasma) and
it said 387watts, so do I have it right that since watts = amps/volts,
this TV will consume 387/120 = 3.2amps , so 3.2 amphours per hour?

Stephen

That's correct. 3.2 Amps at 120VAC, but using the 10% rule, that's
38.7 Amps at 12V through an inverter! Or 32 Amps at 12V if the
inverter were 100% efficient.

The smaller the TV, the lower it's Wattage. As I recall our 16" LCD
was 40 Watts, so about 4 Amps at 12V through the inverter.

Rick

On Fri, 15 Oct 2010 12:21:15 -0400, Wayne.B
wrote:

I'm sure that it's possible to get away with an 80% discharge for some
period of time. I've seen some fairly convincing life cycle charts
however that seem to indicate greatly increased battery life at the
50% level as opposed to 80%. I like to baby our house batts as much
as possible given the expense and difficulty of replacing them.

See "Cycles vs Lifespan" at:

http://www.windsun.com/Batteries/Battery_FAQ.htm

http://img32.imageshack.us/img32/9595/batterydod.gif

(from site: http://www.mpoweruk.com/life.htm )


I agree about babying one's house bank, as long as it doesn't limit
the use of them. Like everything else, it's a trade off.

Here's data from real world experience. It's simply what was, with no
claims:

Back in my EV days, we had a group of about 30 that had built our own
cars or pickups. Each one of them used 20 golf cart batteries in
series.

Note that we all recharged at the C/10 rate ( Amp Hour Capacity
divided by 10 ) and recharged daily. Next to overcharging, the next
best way to destroy a lead / acid battery is to delay charging,
allowing sulfation. We made very sure to keep the electrolyte above
the plates and we did an equalizing charge monthly.

We got an average of 3,600 charges, with a few getting about 7,000.

To explain, our batteries lasted 8 to 12 years. These were our regular
cars. Some of us commuted to work daily. Some barely took the surface
charge off the batts most days, some slmost killed them dead each
workday. That doubled figure were for the few that had really long
commutes and/or their workplace supplied sockets to recharge.

Two of the group rigged up a generator on a trailer to extend their
range. Note they couldn't pull a large enough generator to go
indefinitely, just enough to double or triple the range. The motors
drew about 140 Amps or so at highway speeds.

This seems to say that lead / acid batteries are somewhat like a clock
- wind it up once and it's going to work for X length of time. The
fact that regular car batteries seem to last about 2 years says the
same thing.

Note that we all had several batteries fail at one time or another
during that period. I had one go after a couple months that was
replaced under warranty. I don't remember now just when, but I had two
others go out over the years.

To repeat, we all got 8 to 12 years from our batteries, whether we
discharged them to 10 or 20 or 50 or 70 or 90 per cent daily. We got
many more cycles than the graphs say - most of us should have gotten a
year or two or three. Maybe because we did otherwise baby them, or
maybe because the published figures are worse case, or both?


In any event, if I were to be a weekend sailor and planned on
discharging to 20% or so, I don't think it would be worth it to buy an
extra pair of batteries and have the extra weight and space taken up.
I'd still be getting a pretty long life out of them. Long term
cruising is a different story - I packed 'um in, as many as I could!

Rick