Shore Power and Inverter/Charger use

[Dan Murphy]

We are parked at home and plugged into 50 amp shore power. When I looked at the Magnum control panel it showed the inverter was on. I turned off the inverter and the residential refer went off and the little LED power light went out. So without the inverter on i have no shore power.

Should not the power light indicator come on when I plug into shore power and what about the inverter? Do I need the inverter on at all when plugged into shore power.

Now on the trip home we dry camped at a couple Wal-marts and I ran the Genny for cooking and TV watching but turned everything off to go to bed.I thought that fully charged batts would run my residential fridge thru the night but my batts went down real fast with the inverter on.

I must have something wrong but don't know where to look. anyone have any thoughts about what I may be doing wrong here?
 

[Mike Groves]

Well, not sure what's going on there because in my '99 when the generator is on it supplies power through the inverter and the inverter does show that status but it is off.  In other words if I was watching TV with the generator on then turned off the generator the TV would go off at that point because I didn't have the inverter on.  Sounds like perhaps your coach is different with its wiring and that the generator doesn't go through the inverter.

I am curious as to how much current the fridge is using given that our Marquis is over in Bend right now at RV Outfitters getting a Samsung residential installed.  I was under the impression if the fridge was fully cooled, then it could certainly operate through the night if necessary - at this point I wonder about it.  Perhaps others could share their experience concerning how long dry camping can last with a residential fridge. 

Mike

[Dan Murphy]

Mike
we have been hooked up to shore power all winter so never really tested the res fridge until the trip home.On the second night out I checked the fridge when I turned everything off around 10 pm and it was 38 degrees so I thought it would stay cool also especially since it was cool outside so I turned the fridge off and went to bed. By 6 am it was at 54 degrees so that idea didn't  work very well.
But the night before I turned everything I could think off except the fridge  and ran the fridge off the inverter but the AGS kicked on about 4 am because the batts had got down to 12.1 v.
I was hoping I could turn the fridge off and get thru the night but I don't think so.It is going to need power.
With the inverter running and only the fridge on I used all the battery power up pretty quick.e

[David T. Richelderfer]

First, I am not familiar with a Magnum.  That being said, does the Magnum have to be on to allow shore/generator power to pass through to the coach?  Also, what type of fridge do you have?  My Norcold runs on 110v when shore/generator power is available.  Otherwise it runs on propane/12v.  And my fridge runs all the time (boondocking and not) unless it's turned off at the fridge, or has lost access to 12v power.  Another thought is your heating system (AquaHot, etc.).  Is it turned on and drawing power - either 110v or 12v?  What about TVs and receivers (TV or radio)?

I have six large golf cart House batteries.  They will only barely get us through a night because we leave the fridge on and have the bedroom TV (and receiver) on all night.  Most nights the AGS (Auto Generator Start) will activate after 4 am or so.

[Gerald Farris]

Dan,
Your inverter has a pass-through circuit that should pass the 120 volt shore power through the inverter to the coach circuits that are feed from the inverter regardless of whether the inverter is on or not. Have you checked the shore power lead to be sure that there is nothing wrong there like a tripped breaker?

The problem with the batteries running down overnight, either you are running more from the inverter circuit than you know or your house batteries are getting close to their end of life.

So without checking your battery condition, inverter pass-through circuit, shore power circuit, and amperage draw, I can only suggest that you run those test to determine your problem before attempting any corrective actions.

Gerald   

[Dan Murphy]

Thanks Gerald. Checked the shore power breaker again and even though the breaker was on there was no power to the secondary box where that breaker is. Found the problem I hope.The AGS started about 6pm today and I got to looking into it deeper.

What I don't understand is how the inverter ran the fridge since we got home at 4pm Mon till 6pm Thurs when the inverter wouldn't run it even thru the night on the trip home.Thats weird!

We think the AGS must have been running and we never heard it.

[Neal E Weinmann]

The variations you are experiencing seem perplexing.  Hopefully you're getting closer to solving the issue(s). If there is a wiring diagram available, perhaps that would help.

Some salient points are mentioned in the link below.  Seems like upgrades may be in order to adequately support a residential unit in a (best case) sun supported dry camping configuration:

http://www.gonewiththewynns.com/rv-residential-refrigerator-power

In our '05 Monterey there are a host of power hungry AC circuits that do NOT get fed by inverter supplied AC but work when shore power is furnished or the generator is running - hydro hot AC element, fridge, washing machine, rooftop units, vacuum outlet and the block heater.  The only appliance on one of the inverter circuits is the microwave.  But it's an older coach and has an AC/Propane fridge so I'm sure many things are different.

[Mike Groves]

Wow, according to the Wynns (see the link provided in the preceding post) this fridge - which we just had installed but haven't taken delivery of - may not have been the best bet for us.  I must have misread postings here claiming that it used less power than the AC circuit of the GAS/AC model we took out. My original hope was that after it reached equilibrium that it would require very low power usage as long as it remained closed.  Am I going to be VERY disappointed in this?

Mike

[Ron Johnson]

We just had a residential fridge installed as well and have noticed we need to run the generator more when boondocking. The biggest difference I think is that when boondocking before we had the fridge on propane and cannot do that now. So, we have added a 24\7 draw on the inverter circuit that wasn't there before. I don't believe the power draw is significant but it is 24\7. We have a Magnum 2800 Inverter and a 6 AGM House Bank.

[Mike Groves]

I did realize we wouldn't have the propane, but that also I've converted all the lights in the coach (except closet lights) to LED.  I figured going from 10Watts per halogen light (and 40W per incandescent) that the LEDs of 1 watt (for halogen) and 9 watts (for 40W) would give back more than enough power to run the fridge if we didn't have it open much after dinner.  I don't mind running the generator a while before starting off the next morning or running it for a while as we're on our way, but I would NOT want to have to think about running it in the middle of the night.  Our house batteries are 220Amphrs so I thought someone said that these fridges run on 3 to 3.5 amps.  So if that is continuous isn't that 3.5amphrs which means that if only the fridge was running we'd last for 60-70hrs?  I keep telling my wife that I'll probably be killed due to something electrical because I don't understand it.

Mike

[Neal E Weinmann]

To be clear, I believe that if each 6V battery is 220 AH and you have four batteries total wired in series-parallel, then you have 440 AH total with a 50% useable rating of 220 AH.

[Al Lewis]

On Mike's post, 3.5 amps to run the refrigerator is probably at 120 volts. The same power at 12 volts is 10 times more amps plus some conversion loss. So you are looking at 35-40 amps from the battery. Less than 10 hours should drain the battery.

[Lee Welbanks]

In my 06 PT with this huge refrig i've shut down the gen at 10 pm and in the morning the house battery's are around 12.7 or so.
The 3.5 amp draw would not be constant as the frig only pulls any load when the compressor and fans are running, at night as long as your not opening the door mine will only start up a few time.

[Michael Hannan]

Just for clarification Gerald,  I don't need to have the inverter on at all if I'm hooked up to shore power?  I've been living in my coach full time for just over a year and have had the inverter on all of the time.  I hope I haven't screwed it up that way.

MJ

Dan,
Your inverter has a pass-through circuit that should pass the 120 volt shore power through the inverter to the coach circuits that are feed from the inverter regardless of whether the inverter is on or not. Have you checked the shore power lead to be sure that there is nothing wrong there like a tripped breaker?

The problem with the batteries running down overnight, either you are running more from the inverter circuit than you know or your house batteries are getting close to their end of life.

So without checking your battery condition, inverter pass-through circuit, shore power circuit, and amperage draw, I can only suggest that you run those test to determine your problem before attempting any corrective actions.

Gerald

[Mike Groves]

To be clear, I believe that if each 6V battery is 220 AH and you have four batteries total wired in series-parallel, then you have 440 AH total with a 50% useable rating of 220 AH.

Ok, so Neal, I have 6 of them with every two tied together (series I guess) to form 12V, then those 3 couples are tied together (parallel I guess) to form 12V.  Does that mean I have 660Amphrs with an effective use of 330amphrs? 

When I get to the coach today to pick it up, I'll see what the amp draw is but I certainly thought at 3.5amps was 3.5amps and not 35 amps.  Didn't know there was a difference.  I was thinking it would be 35Watts or thereabouts.

Mike