Shore power, inverter and residential refrigerator GT 351ds

[jcw]

I have a 30 Amp hookup where I store my RV. I was wondering which is a best practice:
1. Inverter off and run on AC for refrigerator
2. Plugged in to 30 Amp but inverter on. This would appear to provide protection against power outages. Not sure if it puts more stress on coach batteries.

Thoughts?

By the way, love this forum site. It has been so helpful as I researched and ultimately bought by 2015 GT 351DS

[rana]

Plugged in to shore power.. inverter off. (I'm assuming you have a residential)

With the inverter on.. yes.. it would provide protection against power outages, however, you're batteries probably won't last very long powering a residential fridge. You're more likely to go out to your rig and find the batteries stone cold dead in that situation.

Short outages shouldn't be an issue since your reefer can maintain temperature for several hours. Long term outages.. I'm sure you'll hear about it on the news, at which time you can power up your inverter or make other arrangements (genset).

I still would not keep many perishables in my unattended reefer.

[The Wandering Irishman]

Hmm, interesting question... We also have the 351DS (2014 model) with residential fridge and wishing I had 30 amp at my storage location.

Is your concern that the power may go out thus raising your fridge temp and spoiling whatever you left in it? If so, I'd leave the inverter on and that way you've always got power (unless power is out for days and your batteries go dead of course). I always have the inverter on during trips whether plugged in or on shore power, never really thought about any negative impacts of that. Hmmm...

Something to consider is a thermometer that has the high/low record, I saw a digital one on Amazon for less than $20. Might give you piece of mind knowing that jar of mayo never got up to 80 degrees....ewwww.

I guess I'll have to dig in a little more on how the wiring actually works for the inverter/fridge. I was thinking that on shore power/generator the auto-switch would allow it to draw power from there and not the batteries. Power goes out, switch goes back to batteries and inverter takes over. Hopefully someone knows how this REALLY works.

Tom

[jcw]

Tom, you hit the nail on the head regarding my question. I assume that when plugged into shore power and inverter is on that the residential refrigerator is powered via AC power either from:
1. Inverter fed by coach batteries, which are in turn continuously recharged from shore power
2. From ATS directly, by passing inverter. However, in case of losing shore power, the refrigerator gets AC power from inverter until coach batteries are exhausted. In this case, I assume the 4 coach batteries can keep the refrigerator going for about 2 days?

Joel

[dan-nickie]

Joel, I would not assume your res fridge will run for 2 days on inverter/batteries.
I did a test on my Berkshire with 4 six volt batteries and it went about 8 hours until the batteries were down 50%.

We leave ours plugged in, inverter off in storage to keep the fridge cold and battery charged.

Didn't want to take a chance on killing 4 expensive batteries.

[rana]

Originally Posted by jcw

assume the 4 coach batteries can keep the refrigerator going for about 2 days?

Joel

That would depend on your type and size of battery/ies. However, you don't really want to discharge your batteries below 50% of their rated capacity. The reason for keeping your inverter off is that it continuously draws power from your batteries if you are actually using it or not. Just as there is a constant parasitic draw on your batteries without having anything actually "on".

In the situation of keeping it on while on shore power in anticipation of a possible loose of power, you run the risk of not catching it soon enough and depleteing your battery/ies to a 0% SOC, which is quite harmful to your battery/ies.

If you will have your rig in "storage mode" over long periods of time, it is also very damaging to your batteries to keep them in a constant state of charge. Your run the risk of "cooking" your battery/ies.

In a nutshell.. doing damage to my battery bank is a much greater risk in my book than loosing whatever few tidbits I might choose to leave in my reefer. If it was just between weekend get-a-ways I would be more comfortable leaving it stocked and running, but even then, I would have my batteries disconnected.

[rana]

Originally Posted by The Wandering Irishman

I always have the inverter on during trips whether plugged in or on shore power, never really thought about any negative impacts of that. Hmmm...

The only real concern there is that it is still drawing power off your batteries.. even when there is no actual load on the inverter. Heat, longevity of your inverter can be affected, as well as burning more electricity. If your are in a metered CG you'll end up paying for the additional electricity with no practical benefit.

A lot of folks do just the same. There is no real "do" or "don't"... just personal preference and convenience.

[jcw]

Yarome,
I did not realize that keeping the batteries fully charged via shore power was a bad thing.... I have always kept other batteries to boats, for example, fully charged via a trickle charger during winter storage? Are you saying that the RV ATS does not do a proper job keeping batteries properly charged over long periods?

[TURBS]

My unit is going on 5 years old with the original batteries and I leave it plugged in 24/7 365.
I must have done something wrong?

TURBS
08 duramax tuned n modded, 32bhok Sabre
2015 camping "9 nights"

[rana]

Originally Posted by TURBS

My unit is going on 5 years old with the original batteries and I leave it plugged in 24/7 365.
I must have done something wrong?

Can you say "Progressive Dynamics charge wizard"? Ohh... that's right.. you CAN!

Completely different animal to a stock converter.

[TURBS]

Originally Posted by Yarome

Can you say "Progressive Dynamics charge wizard"? Ohh... that's right.. you CAN!

Completely different animal to a stock converter.

Paaaaa POW! [emoji109] [emoji12]

TURBS
08 duramax tuned n modded, 32bhok Sabre
2015 camping "9 nights"

[rana]

Originally Posted by jcw

Yarome,
I did not realize that keeping the batteries fully charged via shore power was a bad thing.... I have always kept other batteries to boats, for example, fully charged via a trickle charger during winter storage? Are you saying that the RV ATS does not do a proper job keeping batteries properly charged over long periods?

Disconnected and using a battery tender or the like is my preferred method for long term storage. I guess I should say.. it depends. "Most" stock converter/chargers can potentially harm your batteries if kept power on over a lengthy period of time. What some would call a "dumb" 3 stage charger.

Something like a Progressive Dynamics replacement, with their charge wizard, or similar.. a 4 stage "smart" charger.. then no. Keeping shore power on and connected isn't really an issue.

Of course, type of battery plays a big part, but for the sake of argument, I was assuming that you have some type and size of wet cell.

[The Wandering Irishman]

Our 351DS can keep an already cold fridge and freezer going for around 24 on the 4 house batteries before I recharge them. They are far from dead at that point but quite low.

Great info in this thread, helps me understand a little better how the system works.

Tom


Sent from my iPhone using Forest River Forums

[rana]

It will just depend on what type and size of battery bank you have. Just an average, but most RV sized residential's will run around 6-7amps full load and peak loads around 11'ish.

So.. 6.5amps x 110vac = 715watts
715watts / 12vdc = call it 59amps

It won't be running all the time, but say in a 24 hour period.. 10 minutes on the hour would be 240 minutes / 60... roughly 4 hours of actual run time.

4hrs x 59amps = 236ah's
236ah's + 24ah's (parasitic) = 260ah's

Considering 260ah's a 50% battery bank draw would put you around 520ah's of battery capacity needed to run your residential fridge for 24 hours... providing of course that you don't run anything else (lights, WH, water pump, TV, etc). And of course... we haven't subtracted the juice that the inverter will need to make it all happen. ;-)

That's pretty darn steep. Roughly the equivalent of 6 - 6v GC's.

Based on your own battery bank's available amp hour capacity it should give you a guesstimate of about how long your's will last.

[ChrisAndGarren]

Hi!
We also have the 351DS - our storage only has a 15 amp plug, but here is what we did for all of last year -

Everything turned off except fridge - plugged into 15 amp and we never had any issues. We also have an old cell phone that we downloaded an app called "Power Outage Alarm" that was also connected to the same circuit.
On the few occasions when the power went out (the outlet is a GFCI, and was tempremental until replaced) the phone sent us a text message (the phone is set up as a go-phone) to tell us the power was out. We then knew we had about 24-36 hours to get out there and reset it or figure out what was wrong.
The free version of the app only tells you when it goes off, the $0.99 version tells you when it goes back on.
Our 351 also has the progressive dynamics charge wizard included (it's in the basement by the plug) so there was no danger of frying the batteries. We also have a hard-wired progressive industries surge protector back there as well.
When we were done camping for the year, we winterized, turned everything off (including the fridge and battery disconnect) until we were ready to go camping again.
I LOVED having the fridge all plugged in- we keep things in the freezer, and stuff in the fridge as well - with the cell phone monitor, I'm not concerned that anything will go bad before I can get to it either. Especially when you are a weekend only camper like us, everything I don't have to haul back and forth saves me time and effort.
Just my experience!!!
Garren

[wrapperman]

My understanding is when the shore power is plugged in there is a different ATS that switches the refrigerator over to shore power, bypassing the inverter. Meaning the batteries and inverter are not being used.
A Xantrex ATS is used in my 2013 378XL


Sent from my iPad using Forest River Forums

[rana]

Originally Posted by wrapperman

My understanding is when the shore power is plugged in there is a different ATS that switches the refrigerator over to shore power, bypassing the inverter. Meaning the batteries and inverter are not being used.

If it's a factory install then that is more than likely true... automatic switching. Or rather it's the inverter that has a pass through transfer switch in most cases. However, just being "on" and in idle/standby mode drinks a little juice. Nothing extreme but it is continuous and comes right off the top.

Nothing wrong at all with leaving it on. I just prefer to keep it off when in a storage situation. I would rather risk leftovers than my battery bank.

[wrapperman]

You're right yarome it does have a built in transfer switch. Making it ideal for running the fridge when the RV is plugged in or not.


Sent from my iPad using Forest River Forums

[HookupAndGo]

Garren,

That is awesome about the power out app -- I have always been uncomfortable leaving my pets in the RV when temps are high for fear of having power go out and therefore the AC. Will have to look into this further.

Having this for the fridge is a nice extra benefit that could be handy too.

Thanks! Oh, and sorry to slightly derail....