The Holy Grail

[sjkted]

Hello,

I just put up about 400 watts of solar panels on my '91 Fleetwood Southwind Class A, added a Xantrex 1750 Watt inverter and expanded to (4) 6-volt deep-cycle batteries. I had the idea that I might be able to connect my shore power to a 15 amp adapter to an extension cable into the inverter which is mounted on the passenger storage compartment in the front by the engine bay.

I figured this would be the holy grail because I could access the battery power from any electrical outlet anywhere in the RV, instead of walking up to the front to use one of a few outlets. It didn't work. The inverter didn't seem to even notice anything new was plugged in -- it didn't drop voltage or even show any extra wattage usage. It was as if nothing was plugged in.

I'm not an electrician, but I have a few ideas why it didn't work:

(1) There was a problem with the 30->15 amp converter?

(2) The inverter creates power with rectangular sine waves and the shore power connector is looking for circular sine waves?

(3) The system is intelligent enough to figure out I have created a looping condition. The converter/charger kicks in when I connect to shore power which charges the batteries, but the batteries are being depleted to provide the shore power?

I'm curious as to why this didn't work and I've also heard it's very expensive to wire the inverter into the RV electrical system. Why didn't it work? I appreciate any comments/ideas here.

Thanks,

--sjkted

[madrone]

I don't know what inverter you have or if it is some combo type unit, but I think normally an inverter would be expecting 12v DC power on its input side not 120v AC
shore power. Did you notice smoke coming out of it? Does it still work?

[madrone]

On second reading I think I understand what you were trying and I suspect you have what is called a transfer switch in your system. This device will only allow power from one source, either shore power or inverter power not both at the same time. I think this safety feature is what saved you!

[sjkted]

Quote:

Originally Posted by madrone On second reading I think I understand what you were trying and I suspect you have what is called a transfer switch in your system. This device will only allow power from one source, either shore power or inverter power not both at the same time. I think this safety feature is what saved you!

Yes, I do have a transfer switch. Would it have damaged my inverter or electrical system if the transfer switch didn't block it?

--sjkted

[marcusallen]

Cool idea.

How far is it from the inverter to the batteries and how thick a cable are you using? This is critical. If you expect the inverter to pump out over a 1,000 watts of power, you need to feed it!

Your shore power input doesn't care if the sine wave is true or modified.

You definitely want to turn off your converter when you do this, it is a loop that does nothing but kill your batteries sooner.

[sjkted]

Quote:

Originally Posted by marcusallen Cool idea. How far is it from the inverter to the batteries and how thick a cable are you using? This is critical. If you expect the inverter to pump out over a 1,000 watts of power, you need to feed it! Your shore power input doesn't care if the sine wave is true or modified. You definitely want to turn off your converter when you do this, it is a loop that does nothing but kill your batteries sooner.

The inverter is about 3-4 feet from the batteries. I'm not sure the thickness but I had a professional installer move and check the wiring, so I'm pretty confident it's ok. Is it possible to power the inside of the RV without the converter? And does the converter usually have an on/off switch or do I need to unplug some wiring?

--sjkted

[marcusallen]

The converter should protected by an AC circuit breaker. You should be able to just turn off the breaker.

[sjkted]

Quote:

Originally Posted by marcusallen The converter should protected by an AC circuit breaker. You should be able to just turn off the breaker.

Ok. I'll try this out next time I visit the RV (probably in a few weeks). I'll post the results here.

Thanks,

sjkted

[John Hilley]

Quote:

Originally Posted by sjkted Hello, I just put up about 400 watts of solar panels on my '91 Fleetwood Southwind Class A, added a Xantrex 1750 Watt inverter and expanded to (4) 6-volt deep-cycle batteries. I had the idea that I might be able to connect my shore power to a 15 amp adapter to an extension cable into the inverter which is mounted on the passenger storage compartment in the front by the engine bay. I figured this would be the holy grail because I could access the battery power from any electrical outlet anywhere in the RV, instead of walking up to the front to use one of a few outlets. It didn't work. The inverter didn't seem to even notice anything new was plugged in -- it didn't drop voltage or even show any extra wattage usage. It was as if nothing was plugged in. I'm not an electrician, but I have a few ideas why it didn't work: (1) There was a problem with the 30->15 amp converter? (2) The inverter creates power with rectangular sine waves and the shore power connector is looking for circular sine waves? (3) The system is intelligent enough to figure out I have created a looping condition. The converter/charger kicks in when I connect to shore power which charges the batteries, but the batteries are being depleted to provide the shore power? I'm curious as to why this didn't work and I've also heard it's very expensive to wire the inverter into the RV electrical system. Why didn't it work? I appreciate any comments/ideas here. Thanks, --sjkted

What you want to do will work, however

1. If the inverter is hardwired into your entertainment center you should disconnect that.

2. Turn your converter off by unplugging it, removing the fuse or turning off the breaker.

3. Set your refrigerator to propane.

[sjkted]

I just wanted to update this thread. It took a month to go out on another trip

I tried the new setup and I am still amazed at how well it worked. All I had to do was unplug the converter and it worked immediately! It was really great considering we were able to run everything 24x7 with no noise at all.

All of the appliances I ran worked great including the microwave and it even ran the fridge and microwave at the same time without dropping the voltage. The TV had a little bit of lines through it which didn't happen when I turned the generator on to compare, but it wasn't very serious.

I used some twist-ties to wire the heavy duty extension semi-permanently and my next step is to drill a hole in the compartment housing the inverter and another hole in the compartment for the shore wiring and connect them. When I want to connect to shore power, I just need to disconnect from within the shore power housing and reconnect to camp site power.

Thanks again for all of the help. I would not have been able to figure this one out myself!

--sjkted

[ralper]

You need at least a 1/0 gauge wire from batteries to inverter. Why do you need a charger to charge your batteries when you have 400 watts of solar ???? If your solar does not do the job there is a problem with it. See my post under Boondocking. "Solar That Really Works". I have not had my charger on since I fixed my solar system Nov 09.

I do not have any confidence in so called professional whatevers. Know what should be and insist it be that way.

[sjkted]

Quote:

Originally Posted by ralper You need at least a 1/0 gauge wire from batteries to inverter. Why do you need a charger to charge your batteries when you have 400 watts of solar ???? If your solar does not do the job there is a problem with it. See my post under Boondocking. "Solar That Really Works". I have not had my charger on since I fixed my solar system Nov 09. I do not have any confidence in so called professional whatevers. Know what should be and insist it be that way.

Well, when I'm boondocking, I don't need the converter/charger, but I do need it if I ever go to a campsite with shore power or if I want to run the generator. The solar panels are really great and do pretty much everything, but they won't run the AC, and there is a fixed limit on how much power I have, especially on a cloudy day.

--sjkted

[ralper]

Quote:

Originally Posted by sjkted Well, when I'm boondocking, I don't need the converter/charger, but I do need it if I ever go to a campsite with shore power or if I want to run the generator. The solar panels are really great and do pretty much everything, but they won't run the AC, and there is a fixed limit on how much power I have, especially on a cloudy day. --sjkted

Cloudy days hardly affect my 400 watt system. I survived four cloudy boondocking days and in partial shade with maxium battery drain of 17 %. I do use the power and do not skimp. Is the wire from the panels to the controler and from the controler to the batteries #4 or larger? If not you need a larger wire from the roof junction box down. I used #2 wires.

For A/C a generator is needed. I do not have a generator nor do I want one. I go the high elevations in hot weather.