85 vs 130 liter Isotherm Fridge for new Grandby

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Any advice about the 85 liter Isotherm versus the 130 liter? Will the smaller one be less of a power draw?
Four Wheel recommended the larger fridge as the power draw difference was miniscule. I am planning to order a new Grandby next week and upgrade to solar from my 2007 Grandby. I have the dometic 3 way and when it is over 90 out the fridge is 60 inside.
 
Depends on how you use it. Power draw difference if full would be very little. Storage is the trade off. We really like the storage over the fridge. We do need to stop and refill the fridge, but we do not stay in one place for a long time. If you are staying for a week in one place I would get the larger fridge.
 
Here is some data on power use of the 130 liter model in my 2017 Grandby:

5.5 setting - 92°F at 8 PM, refrig went to 38°F, running continuously, 39 AH used in 12 hrs, 3.25 amp/hr average with 33-34°F minimum internal

This is with both an added in internal and external fan to help cooling.
 
As Bill says, it depends on how you use it, so the best way to help is to tell how we use it.

We’ve now lived with the 130 for two years, including a three month trip, and have been happy with the results. We are big cooks, so carry lots of ingredients—-fresh produce, meats, etc. We both have a fondness for canned soda waters, so that is our key ballast—and ballast is essential to stable temperatures. We usually shop every 5-7 days, depending on what we are up to.

With a small reduction in ingredients and cold water, and a shopping trip just a bit more often, the 85 would be fine for us, but I love the 130 and the easy ability to be out for a full week.

ps. Pints of premium ice cream stay rock hard in the freezer but you need to cut them in half to fit. I have been a bit of a spectacle in many grocery store parking lots as I get out the butcher knife and cutting board and saw the little buggers in half for storage. But then, sitting 40 miles back down a gravel road in the desert and greeting the stars with a dish of Ben and Jerry’s. Dang.
 
I'm not sure it's possible to have too large a fidge in the camper. I replaced my original 3-way with the Isotherm 65 and it is frequently stuffed on a weekend trip with two people and we replenish the beer as we drink it. One of these days I'll probably modify things and put in a 130L but there are a few other things that are higher on the priority list first.
 
I'm with billharr. Storage loss.

We really like the storage above. We went with the 85 in our new Grandby.

The freezer section on both the 85 & 130 are the same size. . . really small. We purchased a TruckFridge that we can run in the cab of the truck while driving and added a 12V outlet on the outside of the camper to keep it under the back bumper when parked.
 
I choose the 85 for my new Grandby, mostly because of the extra storage space on top. I am happy with my choice. The refrigerator seems to have plenty of room for me, even on longer trips, and the storage space is very handy.
 
We rented a Grandby over the holidays that had the 130L refrigerator. Based on that experience, when we ordered our Grandby, we decided to go with the 85L. We will mostly be doing shorter trips (typically a week or less), and we think the 85L will be just fine and a good tradeoff for the extra storage you get as a result of "downsizing". However, if we were planning to do longer trips, I think we would probably have gone with the 130L.
 
Vic, if you like data here is the rest of it from my test runs. Camper was parked in my shop and on shore power during the day with the fridge running to keep it cold. Then unplugged and left running over night on battery only at various fridge settings. Power use was measured by a Victron bmv700. This was August in Memphis, TN so shop temperature was upper
80s or higher at start of test and upper 70s at end. First number is fridge setting and last is internal temperature achieved.

5 - 52 AH in 17 hrs, 3 amps avg, 35-36 °F

4.5 - 39 AH in 17 hrs, 2.3 amps avg, 36-37 °F

4.0 - 31 AH in 14 hrs, 2.2 amps avg, 37-38 °F

4.0 - 30 AH in 14 hrs, 2.1 Amps avg, 38-39 °F

4.8 - 51 AH in 17.5 hrs, 2.9 Amps avg, 35-36 °F

3.5 - 43 AH in 16.5 hrs, 2.6 Amps avg 39-40 °F, 82 outside in morning
 
Seems odd to me that the fridge temp didn't change much regardless of the setting. And the overnight AH surprise me! That's a lot of juice.
 
Vic Harder said:
Seems odd to me that the fridge temp didn't change much regardless of the setting. And the overnight AH surprise me! That's a lot of juice.
Click to expand...
Specs say the 130l uses 5 amps when running, dividing the avg amps by 5 amps should give a reasonable estimate of run time percentage.
This power consumption isn’t that much different power consumption that I see with my Dometic 110l.

Assuming 5 hrs available solar charge time each day says you likely need 50aH/ 5a==> 10 amps charging current + 5 amps fridge & other power usage during the day ==> 15 amps steady current available.

Factor in flat panel mounting, lower angle sun other than summer, or overcast skies & panel wattage requirements climb. Have fun anyway.

Paul
 
Yes, a lot of juice! Which is why I added a Renogy 160 watt flexible panel mounted on the roof next to the existing factory 160 watt panel. Wired them in series to a new Victron 100/30 MPPT controller to greatly improved efficiency over the PWM. That gives me a shot at getting 15 amps from solar. I left the existing factory PWM solar controller wired to the rear solar input connector for using my portable 100 watt panel in case I need more.

Because of this high power use I have regretted choosing the 130L model. I am assuming that the 85L would use less power due to smaller size and less surface area for heat transfer. But may not be proportional to size.
 
No data, but on a recent 3 month drive about, we only pushed the low end of the battery voltage once and that was when we spent a couple of days deep under the cedars around where Washington, Idaho, and Canada get together. As long as we drove a couple of hours or stayed out of the deep forests, we didn’t have an issue. This is with the 130 always full, the factory 160 on the roof, and 2 factory AGMs in the battery box. I have a 100 watt portable for occasional use, but typically only use it in the northwest. We spent most of the trip in the southwest and never even had to watch things.

Other notes: we had some early trouble with the 130 tied to figuring out the confusing latch mechanism and/or putting too much heavy stuff in the door. I will probably add some kind of external latch mechanism to prevent it from popping open on super rough roads. Opening the camper to find your groceries all over the floor is a quick way to learn to NEVER keep milk in a container that does not have a screw top..
 
We love our 130L in a new Hawk. The factory 160 solar with 2x12v batteries works well in the Utah deserts @ 95F+ temps. The fridge sucks a ton of power, but the intense direct sunlight in the desert also cranks the solar input. I don't have any technical data to support my experience. I keep a sixpack chillin always and my wife loves her sparkly waters, plus we take all kinds of food. It's huge. It works well to have a FIFO rotation so there are always cold bevys.

Usage note: I usually try to park with the fridge on the shady side, often using the awning deployed about 3 feet so the side with the fridge won't bake while we hike, boat. I rarely use the fridge vent fan, but it does come in handy when it's super hot in the desert.
 
BigRanchInSky, I am curious to know what setting you leave your 130L fridge on.

My experience is that when outside temps are 90 or above if I have the fridge set on 5 or higher it runs continuously trying to keep up.

Maybe I should stop measuring the internal air temperature with the wireless monitor. One less thing to think about.
 
Straitline said:
Vic, if you like data here is the rest of it from my test runs. Camper was parked in my shop and on shore power during the day with the fridge running to keep it cold. Then unplugged and left running over night on battery only at various fridge settings. Power use was measured by a Victron bmv700. This was August in Memphis, TN so shop temperature was upper
80s or higher at start of test and upper 70s at end. First number is fridge setting and last is internal temperature achieved.

5 - 52 AH in 17 hrs, 3 amps avg, 35-36 °F

4.5 - 39 AH in 17 hrs, 2.3 amps avg, 36-37 °F

4.0 - 31 AH in 14 hrs, 2.2 amps avg, 37-38 °F

4.0 - 30 AH in 14 hrs, 2.1 Amps avg, 38-39 °F

4.8 - 51 AH in 17.5 hrs, 2.9 Amps avg, 35-36 °F

3.5 - 43 AH in 16.5 hrs, 2.6 Amps avg 39-40 °F, 82 outside in morning
Click to expand...
Another data point: I just re-installed my Victron BMV and I see my 130L is using very similar amounts of power as it tries to cool the totally empty fridge down from room temp. Setting at its coldest, I am seeing 3.8A, which included the extra fan I have installed.
 
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