Installing DC/AC inverter

Hi,

Do you plug into the generator?

Many of us just plug in the shore power cord to the inverter. It does require you to disconnect the converter, and, unless there is a massive battery bank, set the fridge to propane.

The process may be automated by setting up a sub panel and an automatic transfer switch.

How do you switch from shore power to gen power now ?
It might be fairly easy to add a third option to the present arrangement.
On mine that would mean wiring the output of the inverter to a socket like the one that has the gen output now.
Then there would be 3 options:
Jack 1 = shore power pole
Jack 2 = generator
Jack 3 = Inverter

Not a lot of people do this, however, because there are a couple of drawbacks.

First, the inverter would be feeding the CONverter which in turn would be trying to charge the batteries that are running the inverter. Not good.

Second, it would be too easy to overload the inverter if you connected to it just by plugging into ANY of the existing AC outlets. And accidentally starting the air conditioner would immediately trip the breaker on the inverter.

While this seems like a logical and simple solution, I think it probably would NOT be. An inverter big enough to run a lot of stuff would be inefficient and would sap the batteries rather quickly.

Most of the electrical equipment in your RV is made to run directly off of 12 V for a good reason.

For an Inverter to produce enough watts to run an air conditioner you will need to provide 120VAC @ around 20AMPS AC Current.

This is going to require around 12VDC at 200AMPS Current. This is around 2400WATTS.

Then you will want this Inverter to run for many hours... Can you image a battery bank that will produce 200AMPS of DC Current to run for 10-12 hours or so over night. You also have the problem of not discharging your battery bank lower than its 50% charge state or your batteries will not last very long. Batteries are expensive.. So this means you will have to come up with a battery bank that will produce 400AMPS of DC current so you can only draw 200AMPS for the 10-12 hours.

Most batteries specs will tell you how many minutes you can draw 12.0VDC for so many minutes. A Trojan T-1275 Battery says it will will produce 12.0VDC at 75AMPS DC current for just 70 minutes. That's just a tad over one hour. Of course this will totally discharge the battery so you really only get to see 35 minuets of use if you don't want the battery to drop below its 50% charge state.

I would think you are talking about 8 to 10 Trojan T-1275's batteries in parallel to even start thinking about this process...

You will also want to use a HD built Inverter... Not one of the $150 types...

I am no expert here so you need to run these type of questions through the experts on here to get the real skinny of what it takes to have an inverter operate your 13,500 BTU air conditioner.

I run a 600WATT PSW Inverter at half power here alot from 6PM to 10-11PM at night only drawing around 22 AMPS from the 255AH battery Bank and by 8AM the next morning it is right at its 50% charge state (Around 12.0VDC)... Then I have to run my generator for about three hours to charge my 255Ah battery bank back up from its 50% charge state to its 90% charge state so I can do this all over again the next day/night run off my batteries. I can do around 12-14 cycles of this 50% to 90% charge states before I have to run a full 12 hours full charge to keep from hurting my batteries. Its not as easy as one would think haha...

I am a very long way from running a 13,500 BTU Air conditioner doing this for sure...

I don't think you will find this to be a feasible thing to do...

Using 10each Trojan T-1275s 12VDC 150Ah 82-lbs batteries will weigh around 820 lbs - Where in the world would you put these batteries in your Toyota Minnie Warrior camper...

Just me blabbing along here - please check with the Battery experts on here to get real numbers... Ask Pianotuna how many batteries and AHs he runs in his full time live in Motorhome... I'm not sure if Don runs his Air Conditioner off the batteries or not...

Roy Ken

Air is going to pull about 130 amps from a 12v battery.
Where is that power going to come from? Because each battery will be lucky to last a few minutes on its own.

Folks by AC he means running the generator, not running the roof air.

Hmmm I think he wants to run his Air Conditioner and Fridge, etc too ???

Well at least he is getting some info on that process as well...

Roy Ken

oops double entry

My intent was to run the fridge and AC while driving off the inverter. I camp where there is no shore power mostly. I would only run the inverter while not driving to power my computer or some such-nothing with a big drain. Even if I was onshore I could set the fridge at a low level maybe. But yes, I intend to use gas for that anyway.
Speaking of which, when I bought this the fridge wouldn't run on gas. I found a rodent nest in the burner box so I cleaned and blew it out, dismantled everything I could and eventually the fridge worked. That was 3 weeks ago. I haven't used the Winnie but today I was repairing the shower faucet and thought I'd fire up the fridge to make sure everything was still OK. The igniter works but I cannot get a flame now. I blew it out, checked gas pressure, made sure I had a spark, etc. All to no avail. Any ideas there? And what about my revised remarks re: the inverter?

brianokeefe wrote:
My intent was to run the fridge and AC while driving off the inverter.

Does this mean Fridge and ROOF Air Conditioner?

We got AC meaning a coupe of different things here...

Roy Ken

Computer is easy with 150 to 300 watts needed. Probably runs at 50 to 70 watts.

Fridge is an additional 300 watts near continuous and will use a lot of power. Get the propane fixed. Need air/fuel and spark. I would assume it is a propane issue such as the gas valve not opening.

Again the air conditioner will be a very large load on the alternator and you need 2000w inverter.