When on inverter am I using the batteries?

valhalla360 wrote:

msturtz wrote:
You are using shore power. The inverters have an internal transfer switch to automatically switch from inverter power to shore or generator power.

For others coming across this thread, it depends on the inverter and how it's wired in.

The specific model the OP has includes the automatic bypass switch not all inverters include this and it's possible, it wasn't wired in (unlikely but possible)

If you have an inverter that doesn't automatically bypass, it's actually fine to leave it on. Assuming it's a good quality true sine wave inverter and you have a charger that can keep up (air/con would need big units), it actually makes a nice power conditioner. The park power may have low voltage, brownouts and spikes. Within reason, the charger won't care and the batteries absorb the spikes and fill in the low spots. Then the inverter puts out near perfect 120v-60hz power to the outlets.

In 99% of the lower end motorhomes the inverters and most combined inverter converters have automatic transfer switches that will select external power when available. This is separate and distinct from the generator automatic transfer switch. In general there is an automatic transfer switch between shore power and the generator (some coach manufacturers bias the generator power when available) and then power is routed to the inverter incoming AC power supply inputs (not the DC side) if power is present on the incoming AC supply line for the inverter that closes an internal relay which turns off the inverter circuit and disconnects the inverter power circuits from the coach. This means the power provided to those outlets is provided by incoming shore power. There are a few variations that are very uncommon some especially older coaches had designated “inverter only” outlets that were only powered by the inverter. This method is very common in the towable market because they generally don’t have onboard generators. Another uncommon system is to have a phase locked paralleled inverter system. These combination inverter converters are generally referred to as “hybrid” inverter systems that will sync their line phase to the incoming AC if available. The inverter and associated EMS system manage the demand by load shedding. This means the inverter may come online and start powering certain circuits if the instant demand exceeds the available AC power supplied. For example, if a coach has 3 15K BTU AC units and the customer starts running the microwave the EMS system may direct the hybrid inverter to start powering the microwave by drawing power from the batteries at the same time it commands the battery charger (also called a converter) to stop charging. This is especially useful if the coach is plugged into a 15, 20, or 30 AMP shore power connection and 50 AMP split phase power is not available. These systems are generally only available on very high end coaches. It is also important to note that most inverters on most coaches provide square wave otherwise known as modified sine wave power not pure sinewave power. Many things do not work well with MSW power.

It's happen before, with other members
Usually with more extensive and expensive repair costs

Always always unplug shore power before starting generator

Turn off shut down generator before plugging into shore power

I 'harp' on this, I'm adamant about it, it's prevents damage and is a safety issue
But some people disagree
Until the flying Sparks, happens to them

pianotuna wrote:

One step down from that are inverter/chargers that allow load support, which may blend power from shore and battery bank.

We have the second one here on your list - a Powerline EMS and Magnum 2812 Inverter. I didn't know it worked that way until I was educated on another forum and then found it in the manual. Pretty cool stuff :)

There are a few inverter/chargers that allow dual 120 volt shore or generator sources to be used together, blending the power. These tend to be quite expensive. (3k and up). They tend to have all the bells and whistles.

One step down from that are inverter/chargers that allow load support, which may blend power from shore and battery bank.

On the second step down, there are some that will switch from shore to battery bank for starting up loads. It is unclear to me which are which.

A very few inverters are also solar charge controllers. I'd look closely at one of these for the future, if my current Magnum 3012 hybrid should fail (again).

There is a "new kid on the block" inverter from Magnum that uses grid tied inverters and a line voltage inverter to eliminate using a charge controller. Of course, it is intended for large installations--but would save about a thousand dollars on doing a solar install.

Finally there are plain Jane inverters.

Unless load support is a desired feature, it is better financially to have a good stand alone inverter mated to a good converter or battery charger.

Can anyone add to this list of inverter/charger types? (Please I'm truly interested, not trying to be a "smart ass")

Awhile back I was on shore power and decided to exercise the generator. Forget the details, but I think a circuit breaker popped in my incoming 120v box inside the RV shed. Now I disconnect shore power before running generator.

My Xantrex 2000 has a power-sharing feature. Not sure what happened. No harm done......but has anybody run their generator when plugged in to shore power ?

msturtz wrote:
You are using shore power. The inverters have an internal transfer switch to automatically switch from inverter power to shore or generator power.

For others coming across this thread, it depends on the inverter and how it's wired in.

The specific model the OP has includes the automatic bypass switch not all inverters include this and it's possible, it wasn't wired in (unlikely but possible)

If you have an inverter that doesn't automatically bypass, it's actually fine to leave it on. Assuming it's a good quality true sine wave inverter and you have a charger that can keep up (air/con would need big units), it actually makes a nice power conditioner. The park power may have low voltage, brownouts and spikes. Within reason, the charger won't care and the batteries absorb the spikes and fill in the low spots. Then the inverter puts out near perfect 120v-60hz power to the outlets.

OK, that's exactly what I needed.

Thanks folks.

SDcampowneroperator wrote:
It is still advisable to switch off the inverter, power appliances directly from shore power.
Inverters are not 100% energy efficient, use more power than they produce, as well as just plain wear and tear on it and the converter. Inverters are expensive, in my experience, finicky.

With the Xantrex inverter/charger, makes no difference is inverter is on or off. When there is an alternate VAC source, it does NOT invert. It does two things (again with switch either on or off): passes through the 120 VAC and activates the battery charger portion of the inverter/charger.

That switch only makes a difference when there is no external source of VAC.

Put your voltmeter direct on the battery. 12.5 or less is using battery power. 13.2+ is not using battery power.

It is still advisable to switch off the inverter, power appliances directly from shore power.
Inverters are not 100% energy efficient, use more power than they produce, as well as just plain wear and tear on it and the converter. Inverters are expensive, in my experience, finicky.