Easy Explaination

[mikeygesus]

My father-in-law, who is an experienced rv'er, didn't believe me when I told him my 2021 Reflection 31mb could run the air conditioner with the on board battery (not plugged into shore A/C power) for a short period of time. I haven't actually been in a situation where I've had to do this, but my understanding is I can do this.
Am I mistaken?
If I'm right, how can I explain to him how this is possible? Disclaimer: I'm clearly not an expert when it comes to electricity and am learning something new everyday with this RV business.

Thanks!

[NB Canada]

You cant


Outside of a generator it will cost many thousands to run a/c off grid

2021 Imagine 2400 BH
2018 GMC Sierra 4x4 crew

[Redapple63]

My father-in-law, who is an experienced rv'er, didn't believe me when I told him my 2021 Reflection 31mb could run the air conditioner with the on board battery (not plugged into shore A/C power) for a short period of time. I haven't actually been in a situation where I've had to do this, but my understanding is I can do this.
Am I mistaken?
If I'm right, how can I explain to him how this is possible? Disclaimer: I'm clearly not an expert when it comes to electricity and am learning something new everyday with this RV business.

Thanks!

The ac’s work on alternating current 120 volts. The batteries only supply 12 bolts. You need an inverter to run the air conditioners with no mains/shore voltage. Even then the startup amperage required may drain the batteries before you can even get the compressor to kick on unless you had “enough” batteries to get through the start up.

[mikeygesus]

Okay, so help me with this one:
I said I'd never been in a situation where I had to do it, but actually that's not completely true.

On one trip, I made a bone head mistake when re-connecting my battery- I crossed the connections negative to positive (in a hurry and I'm not ready to admit I am close to needing readers- you see, I still didn't admit it). I discovered the impact of my error before we left for our trip when we were loading up in the driveway and only half the lights in the camper didn't work. Naturally, I checked the panel and replaced the fuse. We hook up and head on down the road.
We arrived at the campsite, plugged into shore power, everything worked fine (air conditioner, lights, fridge, etc) until the middle of the night. As usual, the carbon monoxide sensor started to "beep" as a low/no power indicator at 3am- the normal time they do this sort of thing. Also, we noticed the air conditioners weren't running.
After searching various forums, we discovered that the likely issue was that the converter fuses were blown. In the morning, I got to the converter and sure enough, both 35 fuses were toast.
***my understanding is that since the fuses to the converter were blown, we were running solely off of the battery for the 12+ hours until the battery got below it's functional level to continue to support the draw.
I replaced the fuses to the converter and went on with our planned vacation, plugged into shore power.

So riddle me this: Was I wrong to assume we were running off of battery the whole time when the fuses were blown on the converter?

Again, please excuse my ignorance!

[Redapple63]

The converter does a few jobs, one is regulate the 12 volt system. It provides a mechanism for the 12 volts from the battery to your 12 volt distribution system. The second job it does is take 120volt power and charge your 12 volt batteries. The third hobbit does is manage the incoming 120 volts from shore power and sends it to your 120 volt distribution panel (circuit breakers). If the converter is dead you will get no voltage to your distribution panel and no ac power.

Conversely, if it is dead, it will not charge your 12 volt batteries and once the capacity is used you will have no power.

I hope that makes sense.

[mikeygesus]

The converter does a few jobs, one is regulate the 12 volt system. It provides a mechanism for the 12 volts from the battery to your 12 volt distribution system. The second job it does is take 120volt power and charge your 12 volt batteries. The third hobbit does is manage the incoming 120 volts from shore power and sends it to your 120 volt distribution panel (circuit breakers). If the converter is dead you will get no voltage to your distribution panel and no ac power.

Conversely, if it is dead, it will not charge your 12 volt batteries and once the capacity is used you will have no power.

I hope that makes sense.

I understand most of that on a basic level. What I still don’t get is how we were able to run the air conditioners for so long if the AC’s don’t run off of batteries?


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[geotex1]

Okay, so help me with this one:
I said I'd never been in a situation where I had to do it, but actually that's not completely true.

On one trip, I made a bone head mistake when re-connecting my battery- I crossed the connections negative to positive (in a hurry and I'm not ready to admit I am close to needing readers- you see, I still didn't admit it). I discovered the impact of my error before we left for our trip when we were loading up in the driveway and only half the lights in the camper didn't work. Naturally, I checked the panel and replaced the fuse. We hook up and head on down the road.
We arrived at the campsite, plugged into shore power, everything worked fine (air conditioner, lights, fridge, etc) until the middle of the night. As usual, the carbon monoxide sensor started to "beep" as a low/no power indicator at 3am- the normal time they do this sort of thing. Also, we noticed the air conditioners weren't running.
After searching various forums, we discovered that the likely issue was that the converter fuses were blown. In the morning, I got to the converter and sure enough, both 35 fuses were toast.
***my understanding is that since the fuses to the converter were blown, we were running solely off of the battery for the 12+ hours until the battery got below it's functional level to continue to support the draw.
I replaced the fuses to the converter and went on with our planned vacation, plugged into shore power.

So riddle me this: Was I wrong to assume we were running off of battery the whole time when the fuses were blown on the converter?

Again, please excuse my ignorance!

Yes, you are mistaken. Your 12VDC circuits, like all lighting, was drawing from your battery but not your AC circuits at all.
Study how the DC side of a camper works versus the AC side. If you're not electrical-savvy, and need convincing, simply disconnect from shore power and try to run an A/C.

Now I'd you have tens of thousands to spend, we can get you fitted up with an off-grid setup that can power your AC demands too!!

[timkoenig]

Your AC thermostat works on 12 volts along with the lighting. So with the converter (battery charger) fuses blown you ran down the battery. When it got low enough the thermostat stopped working so the AC stopped getting the run signal.

[mikeygesus]

Your AC thermostat works on 12 volts along with the lighting. So with the converter (battery charger) fuses blown you ran down the battery. When it got low enough the thermostat stopped working so the AC stopped getting the run signal.

But how were the AC’s running? I just checked with my wife (who’s way smarter than I) and she confirmed it was running.


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[huntindog]

I understand most of that on a basic level. What I still don’t get is how we were able to run the air conditioners for so long if the AC’s don’t run off of batteries?


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Red apple was basically right EXCEPT for the part about the converter managing the incoming AC power. That is wrong. The AC power goes to the breaker box where individual breakers power AC items such as the microwave, air conditioners, AND the converter. When you crossed the battery cables you blew the converters fuses. You did not know it then, but you were running the 12 volt stuff with the TVs alternator and then stored battery power. At 3 AM you ran out of battery power. The Air conditioner quit then, as the thermostat runs off of 12 volts.

IOW: the air condtioner needs 120VAC to run, and 12 VDC for the themostat to control it

Note: In many RVs the 12 volt distribution (fuses) and 120 VAC distribution (breakers) are in the same box, but they are two seperate systems.