Learned something about the inverter

[Jerry Burks]

Usually, I leave the inverter running all the time when on a trip. It does not matter (inactive) while on shore power and it takes over automatically while travelling, keeping the fridge cold. The 300 Ah battery is good for 6-7 hours.

Now, yesterday we had a violent thunderstorm that knocked out power (not yet back) but we did not notice since the inverter was running. Cooked dinner, watched TV and went to bed. Only to awake this morning with the house battery totally empty (the lithium battery shut itself off) and no power to crank the generator. Even the solar controller refused fill the sleeping battery.

Fortunately I have one of these small lithium jump start boxes that I have never used so far and that got the generator going. Now, 30 min later the battery came back to life at 10% charge so we have a chance to crank up the levelers, pull in the slides and leave this place.

Lesson learned: when arriving at the campground, turn off the inverter in case power goes off unnoticed. Or maybe I will install a warning light somewhere.

[rtaggio]

My inverter hasn't been turned off since it was installed over a year ago. Inverter loss/waste/usage is minimal and should not have killed your 300 amp battery IMO, I think something else was drawing your battery down, not the inverter.

[Skip426]

A couple of points .

Read all your inverter instructions .

Systems powered by the inverter may not function with it turned off ; even with shore power supplied .

If your inverter is also your battery charger , then you'll want to leave it on when on shore power .

Some inverters once shore power is supplied and their circuitry has switched to auto by pass to power the otherwise inverted circuits ; won't turn off .

[TacomaJoe]

Originally Posted by rtaggio

My inverter hasn't been turned off since it was installed over a year ago. Inverter loss/waste/usage is minimal and should not have killed your 300 amp battery IMO, I think something else was drawing your battery down, not the inverter.

In OP case, the shore power went out unnoticed. The inverter kept doing its thing making 120VAC until the batteries were drained. My inverter is for boondocking only so not an issue for me.

There may be settings on the inverter to get it to shut itself down before the BMS on the battery goes into low voltage disconnect.

[Cat320]

I turn my inverter on only if I'm going to use it, like on the road. When on standby, it is subject to wear and tear and uses a small amount of power.

As a point of clarification, on an inverter/charger, the inverter function does not need to be on to charge the batteries.

[twinboat]

300 AH in 6 hours is a draw of 50 amps per hour or 50AH.
There is no way your fridge draws near that amount, 10 to 20 amps less then 50% of the time would be average.

Something else is wasting your capacity.

Another lesson, you cant use 100% of your lithium battery. You may want to raise the low battery cut off up a bit.

[bentjm]

Originally Posted by twinboat

300 AH in 6 hours is a draw of 50 amps per hour or 50AH.
There is no way your fridge draws near that amount, 10 to 20 amps less then 50% of the time would be average.

Something else is wasting your capacity.

Another lesson, you cant use 100% of your lithium battery. You may want to raise the low battery cut off up a bit.

He said they cooked dinner - microwave/convection microwave presumably.

He does need to set the low voltage cutoff appropriately.

[bentjm]

Originally Posted by Cat320

I turn my inverter on only if I'm going to use it, like on the road. When on standby, it is subject to wear and tear and uses a small amount of power.

As a point of clarification, on an inverter/charger, the inverter function does not need to be on to charge the batteries.

That depends on the inverter charger.

On mine, off means off.

[Old-Biscuit]

AC Shore power went out-----Inverter continued to supply AC unnoticed

Battery shutdown

Everything worked as designed

[Dutch Star Don]

I've had three DP's since 2005. In 2014 we bought our first all electric and now have a 2019 all electric coach. Since about 2010, we haven't turned off our inverters. One of the purposes of it is to seamlessly transfer power, if there is a power outage. We never leave the coach unattended for more than an all day excursion, about 8-10 hours max. Our batteries could run that long without issue.

For those with AGS, just set it up so it comes on when the batteries get low.

Lastly, I like to know if there are power issues at a park or even when I first connect the coach. I added a green LED in an obvious spot in my coach at the kitchen counter. I can see it when I first walk in or from my recliner. It's powered by an outlet that only operates from shore power. I know I can go look at my front control panel, but this is just so much easier and takes zero effort.

If I feel like that has been a glitch in shore power, I can simply look at the LED.

[Jerry Burks]

Yes, the system worked as designed and the BMS shut off to protect the battery. So I am not complaining but wondering how to prevent such a surprise in the future. Power outages may be rare but do happen. I was lucky that the little jump start box did its job and maybe I buy an old fashioned jump start cable for the 5th wheel as insurance.

Since I like to leave the inverter on out of convenience, I will probably add some warning light or a buzzer to better indicate loss of shore power. The little dim indicator on the inverter control panel is easily overlooked.

As for the consumption, I double checked and my 18 cuft Norcold fridge/freezer (electric/propane) does use about 45-50 amps of battery current through the inverter. Quite a power hog, isn't it?

[Old-Biscuit]

YEP^^^^

Norcold 18 cuft on 120VAC is 5A draw so roughly 55A 12VDC draw

[Ray,IN]

There is no right or wrong method, off or on is user choice, just be aware of total current draw.
appliance current draw table
How to calculate inverter draw with no load

[bduemig]

My inverter has a setting b that sets a battery cutoff voltage to prevent draining the batteries. I would assume this was normal on all inverters, but maybe not.