Junius,

Yes this Battery Charger simply 'plugs' into
the standard 120 Volt AC Wall Outlet.

Looks like a Wall Wart with a Pair of Screw Terminals
to connect the DC Output Feed Wires going to the Battery.

Wall Side - Back View
http://www.gruber.com/images/ebay/55-805000-a.jpg

Front View
http://www.gruber.com/images/ebay/55-805000-b.jpg

DC Output Feed Wires
http://www.gruber.com/images/ebay/55-805000-c.jpg


hope this helps ~ RHF

The so-called sine wave coming out of the inverter will be full of
harmonics. The extension cord could make things worse since it would
radiate these harmonics. Again, why go from 12VDC to 117VAC and then
back to 12VDC? If you really insist on going the inverter route, look
for the buzzwords "pure sine" and get the lowest harmonic distortion
unit you can find.

Still, I'm baffled why anyone would use an inverter. You have gone from
perfection (a battery) to a less than clean power.



Joe Analssandrini wrote:
Hello Junius,

The unit probably would generate noise if one placed it near the radio.
But why would anyone do that? ANY eectrical generator will generate RFI
if a radio is placed close to it. SOMETIMES one has to use common
sense! (That's why they invented extension cords.)

Best,

Joe

wrote:

[...]

I think "modified sine" wave inverters are OK for power tools and
devices that use resistive heating, but I won't power electronics from
one again.


Modified sine (really modified square wave) are hard on almost
anything but pure resistive loads -- even fluorescent lights have
trouble starting on them.

Any variable speed power tool is either going to go at one speed only
or blow the triac (spectacularly) on a modified sine wave inverter.

I can't say enough good things about Exeltech inverters. They are
pure sine wave, less than 1% THD at worst, any power factor, and are
rugged and well-designed. I own three, including one that is powering
the full-tower computer I'm typing this on, along with about a third
of the rest of the house (solar power). It's been running
continuously for 4 years. The other two are in the car, one for tiny
loads and one for larger loads.

Exeltech claims to be in use in the radio rooms of US embassies around
the world, and I certainly believe it.

I don't own stock or have any financial interest. I'm just a *very*
pleased customer.

Exeltech: http://www.exeltech.com
Cheap source for exeltech: http://www.advancepower.net

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

y'all don't want to use an inverter for powering them fancy no good new
fangled so-called radios
or computers. (I could have told y'all that about computers and
inverters before,,, but did y'all ask me first? NO,,, y'all didn't,so
live and learn)
cuhulin

To all who responded to this query - thank you! A most extraordinary
outpouring of experience and knowledge, and it is greatly appreciated.

Bruce Jensen

wrote in message
...
I have a big very heavy Sears Marine deep cycle 12 volt battery (like
the kind used in motorhomes and such like) I bought at the local Sears
store about six years ago.Those kinds of batteries (deep cycle
batteries) shouldn't be drawn down to more than about half capacity,or
so I once read in an article.With proper care and maintnance,deep cycle
marine grade batteries should last ten to twelve years or more.
cuhulin

Yes... I have a similar Sears Deep-Cycle battery. My battery is in one of
those plastic marine battery boxes (Battery Box for Group 24 Size Battery)
and I mounted a five position RigRunner on the top cover (RIGrunner Model
4005): http://www.westmountainradio.com/order_us48a.htm I use PowerPole
connectors for everything.

My battery is under constant maintenance charge from a little battery
charger I built specifically for the purpose. Automatic battery chargers
are also available that allow a constant maintenance charge to be applied to
the battery for unlimited duration without damage to the battery.

1% distortion quoted above by Eric is a very nice number. Both types
of inverters square and sine can cause problems with noise. Do not
confuse high frequency switching noise with lower frequency harmonic
distortion that you would get with square waves. They are not the
same. Noise can come from many different sources within the inverter.

Inverter usually has a small switcher running to generate logic
supplies, fan voltages, and other various houskeeping chores.
Inverter may also have microprocessor dsp, or a simple microcontroller
that runs on MHz clock
Inverter may actually have an intermediate inverter switching at 100kHz
or more to get the low level dc up to a higher dc level compatable with
your AC mains voltage.
Finally the actual output sine or square wave is generated by switching
a big mosfet or IGBT that has very steep edges. 5,000 - 10,000v/us is
a reasonable dv/dt to expect. All of these noise sources will
contribute to the overall problem.

Various techniques are used with inverters in order to mitigate both
radiated and conducted EMI. Proper grounding, routing of wires,
sheilding, and finally filtering are all tools of the trade. Best bet
is to try and minimis=ze it at the source.

For the casual user best bet may be to start with a manufacturer that
others have recommended. Exeltech? LC filters to clean up the output
will help. Can set the filter to just above 60Hz and should do nice
job. WWW.CWSBYTEMARK.COM might be a good source for toroidal powder
iron filter cores.Series traps (directly across the output) might be a
good approach if the noise spectrum is known. Mounting the inverter in
another box could help. Mounting the inverter in a remote area and
using a longer extension cord could help. Wrapping the extension cord
around a Hi Mu core where it enters the shack might help as well.

I design large high performance inverters for a living, but I try to
buy gear that will run off of 12v.

Regards,
Bob

Get a big old Submarine battery.You will need a forklift to move that
Submarine battery around though.My old buddy collects old Railroad
thingys and he has a few of those old timey heavy glass jar Railroad
batteries sitting behind his garage.
cuhulin

www.devilfinder.com Submarine Batteries
cuhulin

wrote:

They spec 1.5% typical and a 2% limit, which is twice as good as I've
seen on other products.


Where's that figure from? Did they relax the spec?

Still, 2% is cleaner than the power lines, so it's hard to argue with.

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940