115 vac inverter can be permanently installed in an RV, and connected
an automatic change-over relay. The relay is wired in such a way
that the normally closed contacts are used for the inverter output, and
the normally open contacts are used when external power is
By connecting this way, inverter power is not used to energize the
coil, saving battery power. You will most likely need to do
some re-wiring in the RV to
the wall receptacles that will be powered by the inverter from built-in
appliances that require external power.
of automatic change-over relay installation (including ATS-30
- Camping World sells a
amp automatic change-over relay for generator use that can be used
as an inverter change-over relay. The relay is the ATS-30 from
Parallax Power Components.
- The 12 VDC converter must not be powered from the inverter
just burn up energy trying to charge the battery while running on the
- Unless you are installing a very substantial solar electric
RV, you do not want to run high power appliances like the microwave,
conditioning, etc. from the inverter. Therefore, those appliances
must be isolated from the inverter output, and powered directly from
115 vac external power bus (see
- There is no point in running appliances from the inverter
that can be
from propane. Examples are the water heater, refrigerator, and
- It is not necessary to connect the 115 vac inverter output
breaker because modern inverters have overload protection built into
The inverter will shut down if overloaded.
- If the inverter is more than 150 watts or so, the inverter
as close to the battery as practical.
- Connect the inverter to the battery and RV ground with
DC current draw by the inverter will be approximately 10 times the AC
it is delivering. A 1000 watt inverter will require 4 - 6
- Power from the battery to the inverter should be fused if
A 1000 watt inverter can draw close to 100 amps, so do the math when
wire gauge and fuse size.
- If it is not practical to install a fuse, be very careful
cannot short to ground or chafe. RV batteries can deliver
of amps of current through a 6 gauge wire shorted to ground. Fire
or battery explosion could result.
- The Xantrex RS-400 inverter that I
my RV has provisions for a remote on-off switch, allowing the inverter
to be turned off when not being used. If the inverter you select
does not have this option, you can: leave the inverter running all the
time as the idle current is less than 300 ma, install the inverter in a
location where you can access the on-off switch on the inverter, or
install a relay in the 12 VDC power wire to the inverter. The
option is not very desirable since the relay will need to handle high
currents, and DC power is required to energize the relay when in use,
using more of the power you are trying to conserve.
Installing an AC inverter must be performed carefully as connections
made to high current DC sources and high voltage AC systems. Be
to comply with all electrical codes and utilize high quality
If you are not sure if you are qualified to perform this installation,
seek professional assistance.
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