Replacing the Dometic 8501 3-way with an Isotherm 115 Freeline compressor fridge. Opinions? Advice? Tips?

TG_Ltd

New member
Hello all you nice people!

I'm getting ready to order this new fridge but wanted to ask you to share your most excellent experience with me.

If you've done this upgrade, please tell me, has the Isotherm lived up to your expectations? If not, do tell. If it has, also do tell :)

And if you have any tips/tricks for my person doing the install, I'd love to hear them!

OH, by the way, I do not have a working inverter but I've been assured the inverter is unnecessary. Agree?

Thanks in advance! :0))))
 
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dharmasprint

Active member
I have an 80 litre compressor fridge in my build. It's a trunk design and runs off of a 12 volt supply. It has freezer and fridge compartments that can be controlled independently. I'm very happy with it compared to the 3 way fridge that I had in my pop up trailer.
 

GaryJ

Here since 2006
Isotherm is a good brand. I have had one for 10 years. The question is, what will you power it with? Battery size? Solar? What about a week of rainy days?

Gary
 

Matt Foley

Down by The River
I have that exact fridge (115 Freeline). I do not really like it. The mounting design is poor, the door has less storage than other models, the shelf layout kind of sucks and doesn't allow for tall containers well, and the freezer door is a bad design that gets damaged when you forget that you have it open, which you will.

I love having a freezer and I think I like an upright fridge over a cooler ( I also have an ARB 50), but if I had it to do over again I'd probably get a Vitrifrigio or a 12v Home Depot fridge (quite a bit taller, separate larger freezer, half the price.)
 

TG_Ltd

New member
Isotherm is a good brand. I have had one for 10 years. The question is, what will you power it with? Battery size? Solar? What about a week of rainy days?

Gary
Thanks Gary, you hit the issue on the head.

I've just discovered that my 2-6v AGM house batteries will NOT service this compressor fridge despite being told by the Isotherm salesperson that my two existing 6v AGMs would run it easily. Fact is, I'd need to add at least 2 more 6v house batteries even when parked in sunny places (I have 200w solar), Even with 4 AGMs I will need to charge (drive or run my generator.) to keep from running my batteries dangerously low. A knowledgable friend sent me this answer to: can I run the Isotherm 115 on my two existing 6V AGMs (each rated @224 amp hours):
"that's 224 amp-hours at six volts, and the refrigerator needs 12 volts. your two 6 volt batteries are wired in series, so they produce 12 volts together, but it's still only 224 amp-hours at 12 volts. in lead=acid batteries, you need to only use the top 50% and recharge when it gets down to half if you want them to last very long, so that's 112 amp-hours. divide by 6 amps and you can run the fridge for 18 2/3 hours from full to half charged batteries. it doesn't' run all the time, except in very hot climates, so you need somewhere to get another 100-120 amp-hours to make it through the next day. 200 watts of solar will produce 80-90 amp-hours of charging on cloudless days."
i.e. I'll need at least 2 more AGMs to even think about running this compressor fridge, 4 more is better but needs to be considered. Upgrading to lithium batteries is possible but would cost about $9000.
Thanks for your question, Gary. Hopefully this info will help others. :)
 

jrod5150

Well-known member
I’m about to do the same thing with my Roadtrek. So tired of the inconsistency with 3 way fridge.

@Matt Foley appreciate the real world information. Was going with Vitrifridgo even before reading your reply. The home depot one sounds promising but I really dont want to modify the cabinet
 

elemental

Wherever you go, there you are.
Thanks Gary, you hit the issue on the head.

I've just discovered that my 2-6v AGM house batteries will NOT service this compressor fridge despite being told by the Isotherm salesperson that my two existing 6v AGMs would run it easily. Fact is, I'd need to add at least 2 more 6v house batteries even when parked in sunny places (I have 200w solar), Even with 4 AGMs I will need to charge (drive or run my generator.) to keep from running my batteries dangerously low. A knowledgable friend sent me this answer to: can I run the Isotherm 115 on my two existing 6V AGMs (each rated @224 amp hours):
"that's 224 amp-hours at six volts, and the refrigerator needs 12 volts. your two 6 volt batteries are wired in series, so they produce 12 volts together, but it's still only 224 amp-hours at 12 volts. in lead=acid batteries, you need to only use the top 50% and recharge when it gets down to half if you want them to last very long, so that's 112 amp-hours. divide by 6 amps and you can run the fridge for 18 2/3 hours from full to half charged batteries. it doesn't' run all the time, except in very hot climates, so you need somewhere to get another 100-120 amp-hours to make it through the next day. 200 watts of solar will produce 80-90 amp-hours of charging on cloudless days."
i.e. I'll need at least 2 more AGMs to even think about running this compressor fridge, 4 more is better but needs to be considered. Upgrading to lithium batteries is possible but would cost about $9000.
Thanks for your question, Gary. Hopefully this info will help others. :)
I have an Isotherm Cruise Elegance 130 (4.6 liter) fridge. My battery system is two 224-amp hour Fullriver batteries in series, so 224 12-volt amp-hours, about 112 usable amp-hours going down to 50% state of charge. I can run it for two days starting with fully charged batteries under comfortable to cold ambient conditions (less than 80 degrees during the day).

The ambient temperature is a big factor; at 65 degrees or less it runs even longer - at 90 degrees and up I don't make it two days. Another big factor is whether your fridge is loaded or not - empty fridges have higher duty cycles. A full-ish fridge, once down to temperature, has a lower duty cycle. It really helps to pre-chill the fridge from a constant power source before embarking on a trip, and to pre-chill all of the food that goes into the fridge.

I think a bit more refined analysis might show your situation to not be as dire as it seems right now.* The price tag for your Lithium solution seems excessively high... I've been thinking about converting, and for $3,000 I would be in very good shape with a lot more usable power than I have now.

* If you are expecting to get four plus days, you'll need to double the batteries from the two-day sizing... a week or more, double again... putting in 200 more watts of solar for a total of 400 watts should, on sunny days, more than restore the power used daily unless you have some other big power sucks.
 
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TG_Ltd

New member
I have an Isotherm Cruise Elegance 130 (4.6 liter) fridge. My battery system is two 224-amp hour Fullriver batteries in series, so 224 12-volt amp-hours, about 112 usable amp-hours going down to 50% state of charge. I can run it for two days starting with fully charged batteries under comfortable to cold ambient conditions (less than 80 degrees during the day).

The ambient temperature is a big factor; at 65 degrees or less it runs even longer - at 90 degrees and up I don't make it two days. Another big factor is whether your fridge is loaded or not - empty fridges have higher duty cycles. A full-ish fridge, once down to temperature, has a lower duty cycle. It really helps to pre-chill the fridge from a constant power source before embarking on a trip, and to pre-chill all of the food that goes into the fridge.

I think a bit more refined analysis might show your situation to not be as dire as it seems right now.* The price tag for your Lithium solution seems excessively high... I've been thinking about converting, and for $3,000 I would be in very good shape with a lot more usable power than I have now.

* If you are expecting to get four plus days, you'll need to double the batteries from the two-day sizing... a week or more, double again... putting in 200 more watts of solar for a total of 400 watts should, on sunny days, more than restore the power used daily unless you have some other big power sucks.

Elemental, thank you so much for this excellent information! Grateful you found this question.

So with my *current set up of 2 AGMs, I can run the Isotherm 115 for 2 days without the need to charge, as long as I pre-cool the fridge and food, and the outside temps are below 80º, below 65º the fridge will stay cold for 2-3 days without running the batteries down. When the ambient temp goes above 90º it'll last only one night. (*I have the same battery set up as you do (two brand new 224-amp hour Fullriver batteries in series, so 224 12-volt amp-hours)

This is all really good to know, thank you!

If I have 4 of these batteries, I can get 4+ days, again, depending upon the ambient outside temps.

(I don't know that I can carry 6 AGMs, I need to check my current Gross Vehicle Weight Rating (GVWR) with water/fuel full and a reasonable amount of stuff I carry for a normal trip. These AGMs are heavy @ 140lbs/set.)

As for upgrading to lithium, I have a 2013 Roadtrek Agile (2500) and have 200w of solar (cannot add more, maxed out on my roof); and since it is the V6 I'd need to get the whole package - lithium, engine generator, big inverter. and removal of the Onan. Estimate of cost is about $7000 in parts and another $1500-2000 installation labor.

Please tell me where/how I could get this upgrade for $3000! Thanks again, your advice is appreciated greatly!

P.S. And please tell me why you chose the Isotherm 130 over the 115? I've been vacillating...
 
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Matt Foley

Down by The River
Elemental, thank you so much for this excellent information! Grateful you found this question.

So with my *current set up of 2 AGMs, I can run the Isotherm 115 for 2 days without the need to charge, as long as I pre-cool the fridge and food, and the outside temps are below 80º, below 65º the fridge will stay cold for 2-3 days without running the batteries down. When the ambient temp goes above 90º it'll last only one night. (*I have the same battery set up as you do (two brand new 224-amp hour Fullriver batteries in series, so 224 12-volt amp-hours)

This is all really good to know, thank you!

If I have 4 of these batteries, I can get 4+ days, again, depending upon the ambient outside temps.

(I don't know that I can carry 6 AGMs, I need to check my current Gross Vehicle Weight Rating (GVWR) with water/fuel full and a reasonable amount of stuff I carry for a normal trip. These AGMs are heavy @ 140lbs/set.)

As for upgrading to lithium, I have a 2013 Roadtrek Agile (2500) and have 200w of solar (cannot add more, maxed out on my roof); and since it is the V6 I'd need to get the whole package - lithium, engine generator, big inverter. and removal of the Onan. Estimate of cost is about $7000 in parts and another $1500-2000 installation labor.

Please tell me where/how I could get this upgrade for $3000! Thanks again, your advice is appreciated greatly!
SOK batteries sells a 206ah Lithium with low temp charging protection for $1029, with 224ah of AGM you have around 112ah or usable battery, the 206ah lithium is more than that. Renogy 3000w inverter is $400. I use a Redarc 50a DC-DC charger/MPPT controller combo at $500
 

VWbrad

Member
I have the Isotherm 115 freeline too. I’m powering with 2 deep cycle led acid 6v golf cart batteries in series. On cloudy days with not much power from solar panels, I will get around 2-3 days before my batteries go into warning. A trick I do is put an ice block or cubes in the freezer to extend another day or two.
 

dharmasprint

Active member
I have two Renogy 100 ah 12 volt batteries in parallel along with 400 watts of solar, a Renogy Rover charge controller. Total excluding the solar was around $2000 CDN through Amazon. Solar was about $1.50/ Watt average across the three panels. I have a feed from the alternator that is limited to 20A. With all the loads, I've never seen my batteries drop below 12 volts.
 

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