House Batteries Disconnect Switch & Inverter

[Community Alumni]

Hi folks. I just purchased a new Newmar gasser, and as I was getting familiarized with the coach, I discovered the 1,200 watt Xantrex inverter will come on when the batteries are disconnected at the kill switch. I was under the impression the battery disconnect switch would completely cut off all connections to the batteries.

I have owned other coaches in the past with inverters but it never occurred to me to turn on the inverter with the house batteries disconnected. Are inverters supposed to bypass the batteries kill switch?

[BFL13]

gemsworld wrote:
When connected to shore power, the inverter screen shows an icon showing the power going from shore power to a light bulb, instead of coming from the batteries. The screen will appear for a short time, even if the inverter itself is turned off. I just want to make sure when I turn the battery disconnect switch to off and I turned off the inverter the batteries won't be drained. As I mentioned before, I've owned coaches before with inverters and never had the batteries die on me while in storage. I was a bit concerned this inverter may have been different than the previous ones I had.

Still assuming you have that Freedom X sine wave 1200w I linked. Yes it is different from the usual inverter. It has the pass through 120v for one thing, and it still draws a a tiny bit of DC when "off" (that 4ma in the spec). Ordinary inverter's are off when off.

Not being a newbie, you will know the 120v breakers circuit markings from the factory can't be trusted, and you have to confirm what each breaker controls. In this case there is a sub-panel for the inverter to confirm what each of its breakers are for too. That should solve the question of whether they wrongly left the converter on the sub-panel.

1200w will not run a 1000w MW (wants 1500w) so for off-grid whole house you will want a bigger wattage inverter. You can have two inverters if that is easier than swapping out the 1200w and putting the MW on the sub-panel.

[CA_Traveler]

dougrainer wrote:

CA Traveler wrote:
Besides the above my Magnum charger/inverter cannot be turned off. Pushing the off buttons places the unit in standby where it still uses some power.

If turned OFF, then it will not come alive when there is a Shore/Genset loss of power. From the Magnum manual. 1st sentence. Doug

Inverter OFF – When the inverter is off, no power is used from the batteries to power the AC
loads, and the status LED will be off. If AC power from an external source (utility or generator) is
connected and qualifi ed on the inverter’s AC input, this AC input power passes through the inverter
to power the AC loads. However, if this AC power is lost, the AC loads are no longer powered
because the inverter is off.
When the inverter is turned on, it operates either by “searching” or “inverting”, depending on the
connected AC loads

OK Perhaps I should have said it uses some DC power.

With all Monaco switches and solenoids off my rig draws 0.3A from the house battery due to safety devices, the charger/inverter and whatever else can't be turned off. That's 216Ah per month of storage which means the battery SOC is 50%.

That's why I installed a disconnect switch on the house battery negative post.

And another switch on the chassis battery.

[dougrainer]

BFL13 wrote:

dougrainer wrote:

BFL13 wrote:
If that inverter is this one, it says:

"Back-up Capability with exceptionally fast transfer time just like the UPS - If incoming shore power is interrupted by external events like brownouts, the Freedom X automatically becomes an independent power source that supplies utility grade AC power to your loads when installed with
DC battery"

IMO you don't want it to automatically come on whenever you disconnect shore power. That means with this model, you do need to be able to disconnect the DC input.

http://www.xantrex.com/documents/Power-Inverters/DS20170805_Freedom%20X%201200.pdf

ALL RV Inverter/Charger's IF TURNED ON, will automatically transfer to Inv connected loads if there is a Shore/Genset loss of power. If you do NOT want this to happen just turn the Inverter switch OFF. Doug

Yes, this is an inverter, not an inverter/charger. I am not clear on what they mean by "off" and "on" since it seems to have a small draw 4ma when in "off mode", but they also mention a draw 0.6a when "on" with no load. It says it can be turned "on" by the ignition switch method or by a manual remote.

Anyway, the owner's manual requires a disconnect on the DC input so that solves that I suppose.

"The DC circuit from the battery to the Freedom X must be equipped
with a disconnect and over-current device. This usually consists of a
circuit breaker, a “fused-disconnect”, or a separate fuse and DC
disconnect. Do not confuse AC circuit breakers with DC circuit
breakers. They are not interchangeable. The rating of the fuse or
breaker must be matched to the size of cables used in accordance
with the applicable installation codes. The breaker or disconnect
and fuse should be located as close as possible to the battery, in the
positive cable. Applicable codes may limit how far the protection
can be from the battery."

https://www.xantrex.com/documents/Power-Inverters/Freedom%20X/Freedom%20X%20Owner%27s%20Guide%20(975...

The OP should make sure it is not set to power the converter by inverter, only when there is "shore power" passing through.

You are correct. An INVERTER ONLY operates as you posted. A 1500 watt Inverter only can have a disconnect switch as long as the solenoid is rated at 150 to 200 amps. Doug

[Gottahaveit]

CA Traveler wrote:
That's why I installed battery disconnect switches on the battery posts for both banks.

Exactly :B

[BFL13]

The required disconnect on the inverter's pos input wire is for that fat wire's ampacity. The RV's battery disconnect will likely be just for the ordinary DC loads on the wire to the DC fuse panel to match that wire's ampacity (way lower than the fat inverter wire)

To turn everything off, you would open both disconnects. That might still leave the LP alarm and radio memory on, so it is back to taking wires off the battery while in storage.

IMO check the OEM installation has the required disconnects. Can't trust those RV builders really.

[Community Alumni]

When connected to shore power, the inverter screen shows an icon showing the power going from shore power to a light bulb, instead of coming from the batteries. The screen will appear for a short time, even if the inverter itself is turned off. I just want to make sure when I turn the battery disconnect switch to off and I turned off the inverter the batteries won't be drained. As I mentioned before, I've owned coaches before with inverters and never had the batteries die on me while in storage. I was a bit concerned this inverter may have been different than the previous ones I had.

[BFL13]

dougrainer wrote:

BFL13 wrote:
If that inverter is this one, it says:

"Back-up Capability with exceptionally fast transfer time just like the UPS - If incoming shore power is interrupted by external events like brownouts, the Freedom X automatically becomes an independent power source that supplies utility grade AC power to your loads when installed with
DC battery"

IMO you don't want it to automatically come on whenever you disconnect shore power. That means with this model, you do need to be able to disconnect the DC input.

http://www.xantrex.com/documents/Power-Inverters/DS20170805_Freedom%20X%201200.pdf

ALL RV Inverter/Charger's IF TURNED ON, will automatically transfer to Inv connected loads if there is a Shore/Genset loss of power. If you do NOT want this to happen just turn the Inverter switch OFF. Doug

Yes, this is an inverter, not an inverter/charger. I am not clear on what they mean by "off" and "on" since it seems to have a small draw 4ma when in "off mode", but they also mention a draw 0.6a when "on" with no load. It says it can be turned "on" by the ignition switch method or by a manual remote.

Anyway, the owner's manual requires a disconnect on the DC input so that solves that I suppose.

"The DC circuit from the battery to the Freedom X must be equipped
with a disconnect and over-current device. This usually consists of a
circuit breaker, a “fused-disconnect”, or a separate fuse and DC
disconnect. Do not confuse AC circuit breakers with DC circuit
breakers. They are not interchangeable. The rating of the fuse or
breaker must be matched to the size of cables used in accordance
with the applicable installation codes. The breaker or disconnect
and fuse should be located as close as possible to the battery, in the
positive cable. Applicable codes may limit how far the protection
can be from the battery."

https://www.xantrex.com/documents/Power-Inverters/Freedom%20X/Freedom%20X%20Owner%27s%20Guide%20(975...

The OP should make sure it is not set to power the converter by inverter, only when there is "shore power" passing through.

[dougrainer]

CA Traveler wrote:
Besides the above my Magnum charger/inverter cannot be turned off. Pushing the off buttons places the unit in standby where it still uses some power.

If turned OFF, then it will not come alive when there is a Shore/Genset loss of power. From the Magnum manual. 1st sentence. Doug

Inverter OFF – When the inverter is off, no power is used from the batteries to power the AC
loads, and the status LED will be off. If AC power from an external source (utility or generator) is
connected and qualifi ed on the inverter’s AC input, this AC input power passes through the inverter
to power the AC loads. However, if this AC power is lost, the AC loads are no longer powered
because the inverter is off.
When the inverter is turned on, it operates either by “searching” or “inverting”, depending on the
connected AC loads

[dougrainer]

BFL13 wrote:
If that inverter is this one, it says:

"Back-up Capability with exceptionally fast transfer time just like the UPS - If incoming shore power is interrupted by external events like brownouts, the Freedom X automatically becomes an independent power source that supplies utility grade AC power to your loads when installed with
DC battery"

IMO you don't want it to automatically come on whenever you disconnect shore power. That means with this model, you do need to be able to disconnect the DC input.

http://www.xantrex.com/documents/Power-Inverters/DS20170805_Freedom%20X%201200.pdf

ALL RV Inverter/Charger's IF TURNED ON, will automatically transfer to Inv connected loads if there is a Shore/Genset loss of power. If you do NOT want this to happen just turn the Inverter switch OFF. Doug

[CA_Traveler]

Besides the above my Magnum charger/inverter cannot be turned off. Pushing the off buttons places the unit in standby where it still uses some power.

[BFL13]

If that inverter is this one, it says:

"Back-up Capability with exceptionally fast transfer time just like the UPS - If incoming shore power is interrupted by external events like brownouts, the Freedom X automatically becomes an independent power source that supplies utility grade AC power to your loads when installed with
DC battery"

IMO you don't want it to automatically come on whenever you disconnect shore power. That means with this model, you do need to be able to disconnect the DC input.

http://www.xantrex.com/documents/Power-Inverters/DS20170805_Freedom%20X%201200.pdf

[dougrainer]

Also, Some RV's the LP and CO2 detectors are NOT connected thru the Kill switch solenoid. Basic rule of thumb is, the Kill switch is for short term disconnect. The BEST way for long term is to remove the Negative cables on both Battery Banks. IF you do not have 120 Shore available for long term storage. Doug

[Community Alumni]

Thanks for the replies. I assumed all along the kill switch disconnected everything, including the inverter.

[wa8yxm]

With kilowatt or larger (i'm not sure of the cut off) inverters and inverter/chargers the STANDARD way of hooking them up is the following

Inverter--Batteries---T--Switch--Housew

The T (Tap) is for thigns that need to be powered FULL time no cut off.

Same for Inverter/Chargers.

WHY 1500 watts is about 150 amps draw from the batteries (NOTE I know that is not accurate but.. Well it is downright close by the time you figure in conversion loss and so on it's amazingly close up to about 1000 watts and not far off above that) and that is a bit hard on the Cut off switch.

Also the inverter needs to be as close as is physically possible to keep the very expensive per foot big 00 ga cables short.