Your 400 watt inverter probably has modified sine wave AC output which will
damage some battery chargers.  There should be something on that in the
inverter operator's manual.   Compare with any warning about non-sinusoidal
inputs in your battery charger instructions.

Presumably you can re-charge your RV's batteries before they go flat while
running the inverter :)

Regards,
Barry

The inverter thing works fine for me. Don't worry about the sine wave
nonsense.. While the inverter does convert dc to ac, guess what, the battery
chargers immediately convert it back to dc and don't give a darn about sine
wave or not. (same with a lot of the wall warts... they change ac to dc). I
use a walmart inverter for the laptop/camera/cellphone/flashlight/etc, and
have never had a problem.

We're in our 5th year of half timing in our RV, and chose to go the
inverter route, with a 300 watt modified sine wave unit costing under
$50. Everything we've tried to run with this unit has run well. In
addition to charging the cellphone, laptop and camera batteries, we can
run the built in TV from it (if we turn the TV on a few times to charge
up the degaussing circuit so it no longer causes the inverter to shut
down on overload) and an electric drill and soldering gun.  I can't
think of other small appliances we've used, but they would also work if
we came upon them.  The inverter has worked fine other than annual
lubrication (by cutting through the label that seals the bearing, and
resealing with tape after adding lube) and cleaning of the computer
style fan that cools it.  We recently changed cellphones, and the new
charger plugs right in to the 110v inverter, no new 12v charger
required.  This works well for us, is flexible, and seemed much less
costly going in.

To run the TV I did wire the inverter directly to a spare 30 amp breaker
on the DC distribution panel with short heavy wire.  It would not do it
from the cigarette lighter plug.

HTH,
Barrie B

Dick,

Unless you plan to power more than laptops, camera, and cell phone
batteries, you sure don't  need the cost, size, or expense of a 400 watt
inverter.

When we travel, either in our Class C, or our Suburban, I have a laptop with
GPS and two cell phones plugged into one of these using a 3-way outlet.  I
also use it to power my two 4-AA cell camera battery chargers.

http://www.radioshack.com/product/index.jsp?productId=2123204&cp=&kw=inverte
r&parentPage=search

http://www.radioshack.com/product/index.jsp?productId=2123203&cp=&kw=inverte
r&parentPage=search

Mine is a 75 watt (60 watt continuous and 75 watts peak) and in more than
two years have never had any problem with the device shutting down due to
overdraw or any problem with the devices powered.

I'm running pretty close to my inverter peak output, because sometimes when
I turn off the ignition, the inverter will kick off because the lighter
socket supply voltage drops from 14.5 volts to the battery 12 volts when the
alternator stops.  Then the load overdraws the inverter and it shut off to
protect itself.

BUT, you don't want to leave these on with the engine off anyway.

By-the-way, I also have a 350 watt inverter that I started off with and a
2,000 watt inverter in the RV, but I still use one of these for the
convenience

Tim

***************************************************************

I see where "Dick Snyder" <REMOVE-dicksnyder@comcast.net> contributed:

BTDT.  We have used our 1500w modified sine wave inverter to power the
laptop's wall wart for many miles - and also successfully used a $25
"Powerline 75 Watt Peak" inverter from (where else?) Wal-Mart. The
only problem with the latter is that it easily jiggles out of the
goofy "lighter socket" - another example of Dumb Design.

Don't ask me why 'puters are not designed to take a straight 12-15vdc
input, but AFAIK no popular model is made that way.

Will Sill
The Curmudgeon of Sill Hill

I have a DC-Laptop battery charger.  It works just fine.  

But, why do you not expect hookups?  We have camped at a number of
state and federal CG's and had electric hookup at many.  And of
course, there are hundreds of very nice campgrounds.  In addition,
small generators are inexpensive and rather quiet (before 10PM)  they
are all LOUD after 10.

Unk

I use the little 175w unit sold at walmart and plugs into the cig lighter.
Charges the laptop, camera batteries, phone, etc.

We have been recharging several cell phones, several laptops, a camera,
walkie talkies, three Palm Pilots, a hand vac, cordless headsets,
rechargeable AA cells, and a cordless drill for over three years from
inverters. Our modified sine wave inverters have never caused a problem
with any of them.

It's a whole lot easier than developing a solution for recharging each
device.

Ok, here is something. I have a 400watt inverter. It will power up a
drill, tv and a shortwave receiver. I plug my laptop wall wart into it
and it shows "SC" for short circuit. Yet the wall wart works fine from
the house outlet to power and charge the laptop? wazzup?  JCB

I bought the optional  (and pricey) 12v charger unit for my laptop as I
thought I could use it on airlines.    Turned out I could only use it if I
traveled 1st class.    It works fine in the truck and plugged into the 12v
outlet in the trailer.   But I wouldn't do it again.   A waste of money for
my purposes.

On the other hand, I have a small, inexpensive, inverter which I plug into
the cig. lighter of the car and have used it to recharge (at separate and
various times) the computer, cordless drill, cell phone, walkie-talkie, and
hand lantern.    Have never experienced any problems with it or any of my
devices.   Don't know anything about sine waves, gonna have to do some
research on this.