2021 320BD -How long can I go boondocking for?

Addison

How long do you think I can camp using the fridge to store food( so only opened a few times a day ) and use minimum lights. Now worried about grey tank and cassette is easy to empty, biggest worry is battery getting low and fridge not keeping cold, again, no tv, no Jensen will be turned on, minimum lights.
We boondocked in a walMart a few weeks back, watched tv for 2 hours , had ceiling fan on and woke up to low battery beeping warning....

Marceline

What is the amp hour capacity of your battery? Do you have any way (solar, generator) to recharge your battery?

Addison

Sorry forgot to add that, has factory solar and just the regular battery that came with the trailer, wasn't thinking when I bought it or I would of had them upgrade it

VictoriaP

Addison said:

We boondocked in a walMart a few weeks back, watched tv for 2 hours , had ceiling fan on and woke up to low battery beeping warning....

Do you know absolutely for certain you had a full charge before you started using things on the trailer? That seems like a bit quicker discharge than I’d expect, but we don’t have much end user data on the Isotherm fridge yet that I've seen.

Addison

Yes, was pluged into my hour 110 for 4 days before, and a 3 hour drive to get there pluged into my truck 

pthomas745

Factory solar?  Have you installed the Victron App?  Do you know if your solar is working?  Were you trying to run your fridge while driving?  Something is not right if after all that charging you were getting "low battery alarms". 

Addison

Yes factory solar, and yes apps up I know it works. Yes the fridge was on while driving but wouldn't it run off the truck charge? 
Either way my question is how long can I go boondocking 

pthomas745

Find the documentation on the fridge and tell us how many amps it draws.  Not every vehicle charges while driving.  Or, it could be the fridge uses more than your vehicle can provide.

With solar working, and knowledge of how much power you are using and balancing your solar input with your amp hour use...you can boondock indefinitely.  But, that isn't necessarily set in stone.  A few rainy days?  A campsite in the shade?  All those things have to be accounted for.

Get into your trailer and find out exactly what your battery is.  How many amp hours?  Get the fridge manual out and find out exactly how many amp hours it uses on 12V.  Next time you are plugged in and the car running, have a look at the app and see if your battery is charging. 

mntrails

Per Creed at NuCamp and the IsoTherm documentation, here's what the refrigerator uses once its at steady state:

According to the Isotherm company website, the Power consumption is 275W per 24Hr. According to the number provided by the company that would be a
little more than 1amp per hour.

The Interstate Battery my T@B came with is an SRM-24 @ ~81 amp hours.  That yields a net 40.5 useable.  Subtracting ~23 amp hours for the fridge, there's a net of 17.5 for everything else.  Personally, I've had the same experience where by the next morning, my battery is down to 12.2 or 12.1 Volts (resting) and really needs a charge.  If the sun isn't out, its not a good situation.

I also carry a group 27 deep cycle wet cell that I think has a capacity of around 90 or 95 amp hours.  When using that battery, I'm usually OK in the morning and as long as there's sun, it will recharge. However I've only been out for short 2-3 day outings so I can't speak to whether it fully recharges with full sun or not.

And no, I don't have a shunt and battery controller  (yet :-) ) - that would really help tremendously in quantifying the energy use.

One other thing I've started to do is put everything into the fridge already chilled and toss in an ice pack into the bottom. Having that solid block of 'cold' seems to help minimize how much it runs.  Once I started doing this, I've been very happy with the fridge - I keep a thermometer in it and it stays at around 35 - 38 even with the outside ambient temp in the mid to upper 80s.

My experience would suggest that for serious multi-day boondocking, one of the higher capacity solutions (dual 6V wet cells, etc) is a better solution that will get you through a cloudy day or two.  The standard Group 24 Interstate seems to be better suited to camping where you can plug into 110V AC.

pthomas745

@mntrails , thanks for the fridge update.  That is pretty efficient.   Another way to calculate the total amp hours over a day the fridge uses would be to assume, with decent sun, and after the solar panel brings the battery back up.....that you would have the rest of the day "free" for the fridge.  So, lets say the battery is recharged by noon, and the sun sets by 6, you would "save" those 6 amp hours...so your fridge use calculation would leave you 23 amp hours for "everything else." (These numbers, of course, are "squishy.")

Compared to the "other" 12V fridges in the Tabs, this is a great improvement.  Greater battery capacity would make this work easily.

4ncar

I I would say with your current battery...your looking at the extent of your boondocking term. Upgrade the batters pronto. I am using dual 6v golf carts rated at 235 ah(1/2 is usable). I also have the luxury of a tv that will charge my batteries even with fridge on 12( I have the older norcold 3 way). Then get a shunt style battery monitor. You will be able to ascertain what each time in the trailer draws, and thus be able to calculate how long you can go before a charge is required.

trimtab

I did some research around the black tank longevity...two people could go ( no pun) for 4.23 days before it really really needed to be dumped..rough estimate...most studies done on 20-25 year olds.  So it depends...( joke intended)  

Marceline

Addison said:

Yes factory solar, and yes apps up I know it works. Yes the fridge was on while driving but wouldn't it run off the truck charge? 
Either way my question is how long can I go boondocking 

The answer to your question is: it depends on your particular setup.

You need to know:

1) Your power storage capacity (aH capacity of your battery)
2) Your power generation capacity (your solar panels) + tow vehicle enroute
3) Your power consumption (how much your fridge and anything else you're using consumes.

One thing I would emphasize is that even the efficient Isotherm will require a fair amount of power to bring the fridge down from ambient temp to 40degrees. So you will definitely want to do that while you're plugged into shore power. If you don't, you're going to chew up a bunch of your battery right off the bat. I have a 2way fridge and when I can't plug in before leaving on a trip I put a chunk of dry ice or a a block of ice in the fridge to cool it down. 

Also, we've heard stories about tow vehicles being incorrectly/incompletely wired and not sending power to the trailer. So you should check that unless you're 100% sure it's correct.

mntrails

@Marceline's comment above regarding the 12V Tow vehicle power is a good one to check.  Mine was fully wired and functional but the 12V contact in the tow vehicle side wasn't making good contact on the 7 pin connector and thus the T@B wasn't receiving it and the battery wasn't charging while driving.  

I picked up a 12V plug USB with Voltmeter (google '12V plug voltmeter' on amazon) and plugged it in the outlet in the T@B.  I can immediately see the voltage of the 12V system/battery with a glance.  So when the tow vehicle is plugged in, it shows around 13.6 which is what the cars alternator is putting out.  When plugged in to AC, it shows whatever charge phase the WFCO is in, and when drycamping, it shows the battery voltage under whatever load and/or solar charge its seeing.  Its not a replacement for a battery monitor but its a good learning aid for this first season to see the voltage level of the system at a glance... and no wiring, cutting, etc or dragging out the voltmeter and probes.

DougH

@mntrails calculations are correct, of course, but I want to quibble, as a former engineer, with the phrase "275 Watts per 24Hr" (whatever that means).  I know I'm just being picky, so if you know the units are wrong, stop reading now.

Watts are Joules per second and is a rate of power consumption.  Why would you divide that by a time unit again, unless measuring how quickly, or with what acceleration, a device can ramp up to full power?  The amount of energy used is more commonly measured in Watt hours or kW hours.  When analyzing solar system sizing you often look at how many Wh per day all your loads use, versus how much sun you can collect in a day.

If they mean it's pulling an average of 275W over a 24 hour period, that's not very efficient.  275W / 12V = 23A.  Run that for 24 hours and you've used 550Ah.  That's like half the load of an small air conditioner.  Run it for 8 hours a day, and you're still using up 183Ah.

One website that discusses load calculations talks about analyzing an older top loading Norcold on 12V with a peak current of 4.8A.  4.8A * 12V = 57.6W.  In a warm environment, the fridge compressor runs 8 hours out of every 24, so 60W * 8hr = 480Wh per day.

So did the Creede and the Isotherm website mean 275Wh per 24hr?  That would make more sense. That means the Isotherm peak current is around 2.75A.  Again based on the 8 hour utilization estimate in a day, that's 22Ah of battery used up every day.  Not bad at all.

And yup, if you go to: 

https://www.indelwebastomarine.com/us/products/fridges-freezers/cruise-marine-refrigerators/medium-fridges-65-100-l/cruise-90-big-classic/

...Isotherm says their 3.1cu.ft. unit uses 520W/24h (whatever that means), and they say the Isotherm CRUISE 65 Elegance uses 360W/24hr (which can be reduced by 50% with the use of the Isotherm Smart Energy Control kit).

In comparison, the small Iceco Go20 in Eco fridge only mode uses 27W or 216Wh/24h (with the 8/24 run time assumption).

So our nüCamp IsoTherm fridge is indeed a wonderfully efficient blessing.

And in trade for making it through my before-coffee rant, here's an infographic of how many Watt hours a day a 100W solar panel will produce by state:

MarkAl

All the above suggestions are good. To add my 2 cents you can't count on factory solar if in a tree'd area or limited trailer exposure is my experience. Also don't use the fan for very long - without the low current upgrade mod or new "PWM" fan it's a current hog. That said I can get 3 days easy in one spot with no solar on our pair of 6V batteries. I'd worry for a 2 day weekend with the standard battery the dealers seem to prefer (w/o having solar recharge). I've had no trouble in any situation now that I've added the remote solar option. I think the factory's 105 watt is okay IF you have good sun access with even the small battery and limited fan use with a pre-cooled refridgerator.

Addison

Thanks way too much info....... I'll let you know how I make out. Fridge will be pre cooled from shore power before I go

BywaysNW

I've got a Milwaukie 18-amp drill with two batteries, a charger, and a "power source" accessory with a usb socket and a standard jack.  I use it to run an OSolar fan instead of the ceiling fan, reading light, etc. I've never run the batteries down because I rotate them and haven't been away from shore power long enough to run both down.  

BywaysNW

Oops. I meant 18-volt, not 18 amp.

ScottG

Addison said:

Thanks way too much info....... I'll let you know how I make out. Fridge will be pre cooled from shore power before I go

Ha ha, welcome to the forum!  ;-)

Seriously, your question was much more complicated than you might have initially thought. Personally I think the best approach is what you just implied--go camping and see what happens. Experience is the best teacher and if you are paying attention you will learn the capabilities and limitations of your own system soon enough!

Addison

Ok my update, we didn't charge our phone using trailer, we didn't put the step out or use lights ever, only used water once a day dry camp mode with the pump only on for about a minute a day
Used alde for hot water once only
We woke up on 3rd morning with a sound from interior speakers, cracking, power was so low couldn't turn stereo on and it seemed like it was trying to conect. Plugged into my truck for an hour with engine running and all was good 

pthomas745

@Addison Find the Victron app for your phone and have a look at your solar charging and battery voltage.  What you are seeing with your battery indicates your solar is not working.

jkjenn

I have the Isotherm Smart Energy Kit installed on my fridge. The jury is still out as I am not sure my battery monitor wiring is quite dialed in, yet.

What I find odd, is that my Victron is showing pretty close the same current draw, whether the fridge is on or off and it seems a little high to me. (4.43)

I think my next step to is to measure how much power is drawn using a Fuse Buddy at the converter.

(Photo edited for size.)

ScottG

Thanks for the update, @Addison. For comparison purposes, I just went camping for four nights with very marginal solar. I have a five-year-old group 27 wet-cell battery that will probably be replaced next year. Our power usage is similar to yours, maybe a little more as we do run the pump and use the lights more than you do, as well as firing the Alde (on propane) one a day. By the fourth morning, my battery was hedging on 12.15 volts. Certainly in need of a charge but still able to keep things running.

Even with a smaller (but newer) battery and marginal solar, I would expect you to make three days without issue. Assuming your battery is good and your solar is functioning (two very big assumptions) I wonder if the key variable is the electric-only fridge. I have the older three-way and run it on propane.

This is relevant as there has been some discussion and concern regarding the move away from three-way fridges in favor of a two-way model. While a modern two-way fridge can be very efficient, it can still be a relative power hog compared to a three-way running on propane.

jkjenn

ScottG said:

Even with a smaller (but newer) battery and marginal solar, I would expect you to make three days without issue. Assuming your battery is good and your solar is functioning (two very big assumptions) I wonder if the key variable is the electric-only fridge. I have the older three-way and run it on propane.

This is relevant as there has been some discussion and concern regarding the move away from three-way fridges in favor of a two-way model. While a modern two-way fridge can be very efficient, it can still be a relative power hog compared to a three-way running on propane.

This is where I am trying to figure out if my I am getting a faulty reading or if I am really drawing 4.43 ah with thr battery on with a phantom drain. My 2015 drew about 1.3ah with phantom drain. There isn't a huge bump from turning on the lights. Running the fan will get me up above 6ah. I am not noticing the fridge making much of a difference.

4.40 amp with no solar will deplete you pretty quickly, even with 225ah battery capacity. A good solar yield from the factory solar on a 2021 T@b (105w panel) will get you around a 4ah charge (60 watts.) That should give you about 2 days, which has been my experience.

I have more investigating to do, but this is what I am 

MarkAl

@jkjenn I watched the video on the Isotherm Smart Energy kit. I don't think it changes the ON or OFF current draw (maybe increases a bit for the monitor). Where you'll see the improvement is the average current draw, as they claim it integrates the ambient temp with the internal set temp to control the compressor based on the projected heat transfer of the system.  I look forward to hearing the results.

VictoriaP

jkjenn said:

I think my next step to is to measure how much power is drawn using a Fuse Buddy at the converter.

@jkjenn This is the first time I’ve seen a Fuse Buddy mentioned. It looks interesting. Is this the correct tool? https://www.amazon.com/ESI-306B-Fuse-Buddy-Tester/dp/B0014DDK5O/ 

jkjenn

VictoriaP said:

jkjenn said:

I think my next step to is to measure how much power is drawn using a Fuse Buddy at the converter.

@jkjenn This is the first time I’ve seen a Fuse Buddy mentioned. It looks interesting. Is this the correct tool? https://www.amazon.com/ESI-306B-Fuse-Buddy-Tester/dp/B0014DDK5O/ 

Yup!

jkjenn

So, my Fuse Buddy confirms what I am seeing on my Victron BMV. The fridge appears to be draining around 4.1-4.5 ah at all times, whether on off and temperature setting seems to make very little difference. 

The fuse is located in the 4th position from the top fuse in the converter and is a 20 amp fuse.

I did notice that it tended to stick to around 4.1 ah until you open the door and the light is activated. Thisn8snwhen it seemed to bump up to 4.5.

(Photo edited for size.)

VictoriaP

jkjenn said:

So, my Fuse Buddy confirms what I am seeing on my Victron BMV. The fridge appears to be draining around 4.1-4.5 ah at all times, whether on off and temperature setting seems to make very little difference. 

The fuse is located in the 4th position from the top fuse in the converter and is a 20 amp fuse.

I did notice that it tended to stick to around 4.1 ah until you open the door and the light is activated. Thisn8snwhen it seemed to bump up to 4.5.

Thanks for the info on the Fuse Buddy. Added to my wish list. 😊

So correct me if I’m reading this wrong, but from what I *think* I’m seeing, the Isotherm uses about twice what an ARB does? That does not seem like a logical choice for a trailer that’s spec’d with a 105 watt panel, typically sold with a stock group 24 battery, and marketed for boondocking.

Hmmm. I dislike my Norcold 3-way, but maybe I dislike it a little less now.

jkjenn

VictoriaP said:

jkjenn said:

So, my Fuse Buddy confirms what I am seeing on my Victron BMV. The fridge appears to be draining around 4.1-4.5 ah at all times, whether on off and temperature setting seems to make very little difference. 

The fuse is located in the 4th position from the top fuse in the converter and is a 20 amp fuse.

I did notice that it tended to stick to around 4.1 ah until you open the door and the light is activated. Thisn8snwhen it seemed to bump up to 4.5.

Thanks for the info on the Fuse Buddy. Added to my wish list. 😊

So correct me if I’m reading this wrong, but from what I *think* I’m seeing, the Isotherm uses about twice what an ARB does? That does not seem like a logical choice for a trailer that’s spec’d with a 105 watt panel, typically sold with a stock group 24 battery, and marketed for boondocking.

Hmmm. I dislike my Norcold 3-way, but maybe I dislike it a little less now.

It doesn't seem to line up with the Isotherm material or what I have seen from reviews of owners of the fridge so I will admit to being a little perplexed.

I do love this little fridge, though. My Norcold seemed to work about 50% of the time on LP and was unusable for long cross country trips using it on DC. There is something to be said for being confident that your food isn't going to be bad when you pull into the campground.