Shore Power and Inverter/Charger use

[Mike Groves]

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.

I hope mine will do the same.  I also understand that the ice maker can be turned off as well.

Mike

[Lee Welbanks]

Mike, What you might want to do is actually test how many amps you frig is sucking down. Need to place a amp probe on the hot line that feeds the frig. With mine I can do this at the breaker panel as the frig has its own breaker and if you remove the cover panel, but be very very careful dealing with live circuits.
Your frig may be pulling more amps for some reason.

[Bill Sprague]

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

I had my inverter on for 12 years.  I did that so various phone chargers and lights would work when I unplugged from shore power. 

[Keith Cooper]

In addition to the amp hour conversion from 120v 3.5amp to 12v 35 amps, you need to take into account the inverter efficiency typically 90% to 95 % . For example  at 90% efficiency the draw is approximately 38.9 amps. finally even when everything else is"turned off" there is parasitic load form a variety of sources and that will allcontribute to drawing down your batteries

[Neal E Weinmann]

Correct calculation, Mike. 3 battery "pairs" @ 220Ah each = 660Ah w/ 50% = 330 Ah. The six-battery set may just give you the current needed to maintain overnight operation. I'll be interested to read your report once you've got some results.

[Mike Groves]

Correct calculation, Mike. 3 battery "pairs" @ 220Ah each = 660Ah w/ 50% = 330 Ah. The six-battery set may just give you the current needed to maintain overnight operation. I'll be interested to read your report once you've got some results.

We took delivery of our remodeled 1999 Beaver Marquis from RV Outfitters yesterday.  I'll be posting a "review" of RV Outfitters on another thread.  The new Samsung 18 model was up to temperature and lots of ice had been made so evidently it had been running and had reached equilibrium.  I ran the generator on the way home and once home (at about 6:30pm) I turned everything off except the inverter and the fridge.  I did switch off the ice maker which would be normal for us to do if we were dry camping.  I spent the night with dog in the coach on the street - to protect our investment since we live in SE Portland - and left the outside light on and the light in the "glass cabinet" on.  In other words the same as I've done in the past.  I did note on the Prosine Control that when the fridge was cycling, the lowest 2 LEDs were switching back and forth (2 amp to 5 amp back to 2amp, etc).  That, to me would indicate the fridge was requiring between 2 and 5 amps (if that is indeed the scale units on the Prosine panel).  This morning I got up about 5:45am left the coach on the street, fridge is still on so its now 6:41 and the fridge has been cycling on and off all night on inverter power (12 hours or so to this point).  This would be an overnight simulation as all parasitic draw (TV/Sound Bar etc were on but in standby mode).  Typically in a dry camp situation I do cut all inverter power by turning off the inverter at bed time but obviously that won't happen any more with the fridge now having been replaced.

I'll post later when we return to the coach this morning.  I'll note the LEDs on the prosine panel in so far as voltage and also then turn on the CMP and get the actual voltage and let you know my specific experience.  If this fridge is drawing 35amps (which I can say I don't believe) and I have only 330amp hours then that's only 9 hours of operation which clearly I've now blown past, so I truly think that its running on 3.5 or 3.8 or whatever that number is.  And that's with all due respect to the post saying that on the inverter you multiply by 10.  I simply do not agree but as with everything I stand ready to be convinced. 

Mike

[Bill Sprague]

In other threads, Marty wrote about converting to a Samsung in their PT.  He did all the work himself.  They have 4 fresh Costco golf cart batteries.  It was not built with room for 6.  After the installation of the fridge, he monitored it carefully for battery draw down.   I recall his conclusion was that the fridge compressor runs little that he has no issues with dry camping.  Nor does it work hard enough to excessively work the alternator when on the road.  It may be due to new appliances have to be compliant to low energy use. 

It has been about a year since his installation.  Call or email Marty if you need more info.

We have a Samsung in the condo that is typical of the ones used in motorhomes.  Turning the ice maker off will save on amp consumption.  There are several other selection buttons including "E Saver" or "energy saver" that may make a difference.

[Edward Buker]

Mike,

The 120V AC amp requirement of the frig times 10 is a little low, maybe 12 would be right given there is efficiency loss within the inverter, some of the energy is consumed by heat created by the electronics. That being said that level of power (amps at 12v) is only required during the time the compressor is on, so assume that you run 20 minutes three times a night at 3.5 amps at 120v or one hour total as an example. That would be 12 times 3.5 amps or 42 amps for one hour which is 42 amp hours. While I believe in total you will consume more than that amount with defrost cycles, background electronics of the fridge and coach, you an see that you should have capacity for at least a night and part of a day if managed.

Later Ed

[Mike Groves]

We passed our dry camping test (basically when we need to overnight in a Walmart Parking Lot) and the fridge passed.  After 13 hours I terminated the test and turned the fridge off as we'll be returning to storage mode until end of May.  The prosine still showed green led but it was lower than 12.5 (I think that's the first led for 12V) so the next one down was 11.5 (again its not in front of so I am not sure).  So I turned on the CMP and the house batteries were at 12.3.

Mike

[Gerald Farris]

MJ,
If you are on shore power, the inverter does not operate even if it is turned on because it goes into standby mode as soon as it senses 120 volt input from either the generator or shore power. The only difference in having the inverter on or off is that it will immediately turn on and start producing 120 volt current if there is a disruption in shore power if in standby mode. So most owners leave the inverter on (standby) when on shore power, but it is just a personal choice. However, you should always leave the converter (battery charging) portion of the inverter on when on shore power to keep your batteries properly charged.

Gerald