How to stay longer off grid (compressor fridge).

[cyberyacht]

Mine has so much stuff in the fridge, every time something is extracted it entails repacking the fridge.

 

[Grianan]

Just looked at the technical specifications of the updated model of our compressor fridge. Thetford claim, if you have 2 x 95amp batteries, you should get 8 days use.…..I’m assuming that is with nothing else switched on of course.

We’ve got 2 x 110amp batteries and a 130w Solar panel.

We usually charge iPads and phones when on the move. Not expecting 8 days, but 4 should be achievable surely? We usually only hang around a maximum of 4 days before moving on anyway.

That doesn’t sound right … we don’t have TV, use LED lights and no where near 8 nights if we are static …

 

[Sapper520]

That doesn’t sound right … we don’t have TV, use LED lights and no where near 8 nights if we are static …

Nearest model to ours………..

 

[Hoovie]

Nearest model to ours………..

View attachment 551989

Don't want to rain on your parade, but let's do some maths shall we?

Thetford claim 8 days on 2 x 95Ah batteries in that document, yes?

They then say the fridge uses 280Wh/Day (0.28kWh/24Hrs)
a 12V 95Ah battery has a quoted capacity of 1140Wh (12 * 95). So a pair of them is 2280Wh, yes?
divide 2280/280 and you get 8.14.

So if you used your batteries for nothing else whatsoever, and you drained them down to 2% SOC, then yes you would get 8 Days (I'm ignoring the Fridge cutting out due to a low voltage situation. If we are ignoring other realities, may as well ignore that one as well).

So the real question is "should you believe marketing information based on nothing in reality"?


If you work on the popular mantra of not dropping your batteries below 50% SOC, then on the Thetford energy consumption numbers, you might get 4 days IF YOU HAD NO OTHER USE FOR THE BATTERIES.
If you also used lights, TV, water pump, chargers for phone, fans on heaters, etc, then who knows but a lot less than 4 days.

 

[Sapper520]

Don't want to rain on your parade, but let's do some maths shall we?

Thetford claim 8 days on 2 x 95Ah batteries in that document, yes?

They then say the fridge uses 280Wh/Day (0.28kWh/24Hrs)
a 12V 95Ah battery has a quoted capacity of 1140Wh (12 * 95). So a pair of them is 2280Wh, yes?
divide 2280/280 and you get 8.14.

So if you used your batteries for nothing else whatsoever, and you drained them down to 2% SOC, then yes you would get 8 Days (I'm ignoring the Fridge cutting out due to a low voltage situation. If we are ignoring other realities, may as well ignore that one as well).

So the real question is "should you believe marketing information based on nothing in reality"?


If you work on the popular mantra of not dropping your batteries below 50% SOC, then on the Thetford energy consumption numbers, you might get 4 days IF YOU HAD NO OTHER USE FOR THE BATTERIES.
If you also used lights, TV, water pump, chargers for phone, fans on heaters, etc, then who knows but a lot less than 4 days.

Rarely believe any specifications put out by manufacturers, and definitely wasn’t taken in by Thetfords.

^{_{Subscribers  do not see these advertisements}}

 

[Grianan]

Don't want to rain on your parade, but let's do some maths shall we?

Thetford claim 8 days on 2 x 95Ah batteries in that document, yes?

They then say the fridge uses 280Wh/Day (0.28kWh/24Hrs)
a 12V 95Ah battery has a quoted capacity of 1140Wh (12 * 95). So a pair of them is 2280Wh, yes?
divide 2280/280 and you get 8.14.

So if you used your batteries for nothing else whatsoever, and you drained them down to 2% SOC, then yes you would get 8 Days (I'm ignoring the Fridge cutting out due to a low voltage situation. If we are ignoring other realities, may as well ignore that one as well).

So the real question is "should you believe marketing information based on nothing in reality"?


If you work on the popular mantra of not dropping your batteries below 50% SOC, then on the Thetford energy consumption numbers, you might get 4 days IF YOU HAD NO OTHER USE FOR THE BATTERIES.
If you also used lights, TV, water pump, chargers for phone, fans on heaters, etc, then who knows but a lot less than 4 days.

I think what it highlights for me is just how much I’m using with water pump, lights snd charging the phone.

 

[Lenny HB]

I think what it highlights for me is just how much I’m using with water pump, lights snd charging the phone.

Not much, its the fridge that's hammering the batteries.

 

[Minxy]

Not much, its the fridge that's hammering the batteries.

Agree, when we had a 3-way fridge we never had issues but when we had a compressor one it was a pain in the bum and we were constantly checking the battery level, it was one of the main reasons we decided to change MHs and were happy to get shot of it.

 

[Lenny HB]

one of the main reasons we decided to change MHs and were happy to get shot of it.

Why don't I believe that, going from a PVC to an A Class.

 

[Minxy]

Why don't I believe that, going from a PVC to an A Class.

If the A-class had a compressor fridge we wouldn't have bought it ... seriously.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

I really don't get this move to compressor fridges in PVC's stupid when the van is not big enough to fit enough batteries or solar to power the fridge. Cost saving gone too far. At least Carthago Malibu PVC's give you the option of a 3 way fridge.

 

[Hoovie]

new 3-way in my Motorhome would have cost around £1500 retail
fitted a compressor Fridge-Freezer .... £270 (and sold the old 3-way for £170)

bit of a saving there (and I am sure the 500Ah of Lead (AGM ) and Lithium hybrid battery at £900 will cope )

 

[Minxy]

I really don't get this move to compressor fridges in PVC's stupid when the van is not big enough to fit enough batteries or solar to power the fridge. Cost saving gone too far. At least Carthago Malibu PVC's give you the option of a 3 way fridge.

I believe if you order a Globecar you can also specify a 3-way too in models where one can be realistically fitted.

 

[davidroxburgh]

While Lenny may be right, for me 200Ah of lithium plus solar and B2B or good charging direct seems the right mix with a compressor fridge. I wonder how long before lithium becomes forced on PVC suppliers with compressor fridges and (in my case) a diesel heater.

 

[QTECH]

Set up PVC
1x 115a Battery (new)
1x 160 solar with mppt (new)
Vitrifrigo C90 45w fridge
I had problems maintaining a reasonable voltage in the battery. At Malvern this year most mornings voltage on leisure battery was 11.8 the weather was good so battery recovered quite quickly, but not ideal. This got me thinking that come late Autumn I could have problems
Started looking into options, no point in going for 2 battery option without increasing solar, and being a Yorkshire man the £ signs were flashing. Got to thinking does the fridge really need to kick in through the night, which this one does frequently, probably not. The fridge and freezer are always full when away, even if it is only beer, wine, tonic and ice. So started a trial switching fridge off at 10pm temp reading 0 switch back on 6.30 am temp reading + 6 mildish weather so not good. Tried various combinations and realised the fridge needed to be on for a limited time around 2am.
Looked into 12v timers and found one highly recommended by narrowboat owners, so £12 and 4 hours off my time (1hr spent getting a neg wire to the timer) I believe I’ve a solution that suits me. Battery reading is now 12.3 and temp 0 to + 2 at 6.30 am. The fridge stat is at minimum so there is leeway come summer. Hope this may help someone.

^{_{Subscribers  do not see these advertisements}}

 

[Cornish Crew]

I am with the only one other lateral idea I have spotted. Don't use the fridge so much.
Through autumn & winter we never have the fridge running overnight, it will stay cold enough for what we keep in it, milk being the lost critical, even then if you use the filtered variety now available, that easily keeps. Like everything with a van its horses for courses, but if you try to live the same way as you do at home you will always struggle, conversely if you use the good habits from the van at home surprising how much power & water you can save.

 

[stewartwebr]

Have you considered how the fridge operates? We opted for a compressor fridge freezer on our latest Morelo. We are absolutely delighted with its performance and would never go back to adsorption. It may be worth reviewing how you are feeding your fridge to use the most effective method of supply. As you may be aware an inverter is not efficient and does consume power even if not supplying power, the fact it is connected means it is consuming valuable power and your fridge doesn’t require constant supply. How Morelo designed ours is to use its own small inverter exclusively for the fridge. It is on a control circuit along with the fridge compressor. When the temperature increases in the fridge and the system requires the compressor to run to cool the fridge, it also calls on the inverter to switch on. Doing this means you do not require an inverter to be constantly on using valuable power. It would not take much to design such a circuit. Our fridge freezer consumes around 10a/h per 24 hours so not a huge demand.

 

[Hoovie]

Have you considered how the fridge operates? We opted for a compressor fridge freezer on our latest Morelo. We are absolutely delighted with its performance and would never go back to adsorption. It may be worth reviewing how you are feeding your fridge to use the most effective method of supply. As you may be aware an inverter is not efficient and does consume power even if not supplying power, the fact it is connected means it is consuming valuable power and your fridge doesn’t require constant supply. How Morelo designed ours is to use its own small inverter exclusively for the fridge. It is on a control circuit along with the fridge compressor. When the temperature increases in the fridge and the system requires the compressor to run to cool the fridge, it also calls on the inverter to switch on. Doing this means you do not require an inverter to be constantly on using valuable power. It would not take much to design such a circuit. Our fridge freezer consumes around 10a/h per 24 hours so not a huge demand.

I would be quite amazed if, and am rather sceptical, you have a fridge/freezer that uses 10Ah in 24Hours. That is, TBH, not feasible IMO. Would you post a link to the fridge model? If that consumption was right it would revolutionise campervan food cooling!
If it is really 10Ah/day, than that is brilliant
(I am assuming you mean 10Ah @12V? If it were @24V it would still be remarkable. @48V it would be ok.)

Also, you don't need to have the fridge thermostat linked to the inverter for have an efficient setup. Lots of decent inverters will stay in a standby mode (called different things by different makers. Victron call it ECO on one range of inverters, and AES (nothing to do with fridges) on another).
My Victron Multiplus is setup in AES mode and wakes up when the fridge needs power and then when the fridge compressor stops, goes back to sleep. So this time of year, wakes up every 150 minutes and is on for about 20 minutes in that 150 minutes.

 

[stewartwebr]

I would be quite amazed if, and am rather sceptical, you have a fridge/freezer that uses 10Ah in 24Hours. That is, TBH, not feasible IMO. Would you post a link to the fridge model? If that consumption was right it would revolutionise campervan food cooling!
If it is really 10Ah/day, than that is brilliant
(I am assuming you mean 10Ah @12V? If it were @24V it would still be remarkable. @48V it would be ok.)

Also, you don't need to have the fridge thermostat linked to the inverter for have an efficient setup. Lots of decent inverters will stay in a standby mode (called different things by different makers. Victron call it ECO on one range of inverters, and AES (nothing to do with fridges) on another).
My Victron Multiplus is setup in AES mode and wakes up when the fridge needs power and then when the fridge compressor stops, goes back to sleep. So this time of year, wakes up every 150 minutes and is on for about 20 minutes in that 150 minutes.

Okay so you obviously know best, I was just trying to be helpful and explain what Morelo have done and I find very effective, but I shall say no more as you appear to know best. But what I would add is that when your inverter “wakes up” it is waking up I assume a larger than required inverter which is not efficient. The power consumption is what my onboard system records not that it has much impact on my 4 x 210Ah Super B lithium battery bank.

 

[Sapper520]

Okay so you obviously know best, I was just trying to be helpful and explain what Morelo have done and I find very effective, but I shall say no more as you appear to know best. But what I would add is that when your inverter “wakes up” it is waking up I assume a larger than required inverter which is not efficient.

We’re happy with our Compressor fridge / Freezer in our PVC. 90L capacity which is more than ample for our needs and is extremely efficient. Three weeks away, okay, only a couple of nights off EHU, but more than happy. We’re not heavy electric users in any case.

^{_{Subscribers  do not see these advertisements}}

 

[funflair]

I would be quite amazed if, and am rather sceptical, you have a fridge/freezer that uses 10Ah in 24Hours. That is, TBH, not feasible IMO. Would you post a link to the fridge model? If that consumption was right it would revolutionise campervan food cooling!
If it is really 10Ah/day, than that is brilliant
(I am assuming you mean 10Ah @12V? If it were @24V it would still be remarkable. @48V it would be ok.)

Also, you don't need to have the fridge thermostat linked to the inverter for have an efficient setup. Lots of decent inverters will stay in a standby mode (called different things by different makers. Victron call it ECO on one range of inverters, and AES (nothing to do with fridges) on another).
My Victron Multiplus is setup in AES mode and wakes up when the fridge needs power and then when the fridge compressor stops, goes back to sleep. So this time of year, wakes up every 150 minutes and is on for about 20 minutes in that 150 minutes.

I think that MORELO were fitting the Dometic 10 series compressor but might be moving over to something else soon, according to the Dometic specification for the 10 series compressor the consumption for a 24H period @12v seems to be in the range 40ah to 70ah so OK a bit more than stewartwebr suggested but he makes two very valid points, the first being the way the fridge/van electronics handles the switching of the small inverter that is dedicated to the fridge and secondly when you have 840ah of LiFePO4 and no doubt a roof full of solar you don't really worry that much.

EDIT actually MORELO may already be using the Siemens fridge freezer in the Empire Liner and it is is possibly more efficient than the Dometic offering.

 

[Hoovie]

Okay so you obviously know best, I was just trying to be helpful and explain what Morelo have done and I find very effective, but I shall say no more as you appear to know best. But what I would add is that when your inverter “wakes up” it is waking up I assume a larger than required inverter which is not efficient. The power consumption is what my onboard system records not that it has much impact on my 4 x 210Ah Super B lithium battery bank.

It isn't a matter of knowing best, which is why I asked you what your fridge/freezer, that uses an incredible average of under 6Wh/Hr, is.
So please do say more and tell us the model? I looked up the Morelo Empire Liner and the only fridge listed is the standard Absorption type. How about sharing your amazing setup in more detail.

I used to use one inverter on the Fridge and another bigger inverter for bigger loads on a previous van, but decided to use just one inverter on the current motorhome as that is a more efficient use of money with minor extra impact on power use.
I would hope 10Ah in a day would not impact your 840AH of Lithium (you will really need every Amp saved on your tiny setup )

 

[Richard n Ann]

How much a fridge consumes depends very much on the ambient temperature it's in. Imagine a coolbox outside in winter, it will use nothing

 

[Hoovie]

I think that MORELO were fitting the Dometic 10 series compressor but might be moving over to something else soon, according to the Dometic specification for the 10 series compressor the consumption for a 24H period @12v seems to be in the range 40ah to 70ah so OK a bit more than stewartwebr suggested but he makes two very valid points, the first being the way the fridge/van electronics handles the switching of the small inverter that is dedicated to the fridge and secondly when you have 840ah of LiFePO4 and no doubt a roof full of solar you don't really worry that much.

yes, a "bit" more (4 x the energy at least!).
I am all for efficient fridges and have spent a long time researching energy-efficient and cost-efficient options in that area (there is no point in achieving one without the other) and 10Ah/Day is just not going to happen and gives a totally wrong idea to other people of what is actually likely or even possible (hence my earlier post and dissection of the Thetford "will run for 8 days" promise as people see that kind of thing and just end up disappointed).

 

[olley]

Fridge has to stay on to keep the ice frozen in the freezer compartment, wife must have ice in her wine or I am in trouble.

^{_{Subscribers  do not see these advertisements}}

 

[Garratt]

I really don't get this move to compressor fridges in PVC's stupid when the van is not big enough to fit enough batteries or solar to power the fridge. Cost saving gone too far. At least Carthago Malibu PVC's give you the option of a 3 way fridge.

My Dreamer D55+ and its fellow Rapido panel vans have 3 way AES fridges. It was one of the deciding factors for me when we bought the van. I wouldn’t want a van with a compressor fridge, which is why we didn’t choose an Adria Twin.

 

[Minxy]

How much a fridge consumes depends very much on the ambient temperature it's in. Imagine a coolbox outside in winter, it will use nothing

... and how many times you open the door to retrieve a beer!

 

[69473]

Thought I would update on how my lithium batteries performed compared to last year with AGM.
Briefly last October we travelled to the Lake District for half-term and experienced three days of horizontal lashings of rain, as a result confined to the van by the end of day two are 2x95ah batteries were practically depleated with 200 Watt's of solar contributing practically nothing.
I should point out we have a compressor fridge and diesel heating. We are not particularly heavy user's, no tv, hair dryers or coffee makers afterall its only a 6m PVC, however we do have teenagers with various devices.
AGM'S were replaced by lithium at RoadPro and off we went back to the Lakes to give them a comparison test.
The lithium batteries had performed perfectly all summer however I had doubts about the comparison as I didn't think I could replicate the poor weather of 2020.
Oh how misguided I was !
We stayed at the NT site at Wasdale head little did we know how the three days would pan out.
The drive along the lakeshore to Wasdale is a single track road with a number of passing places.
We arrived as it was starting to get dark and the road was unusually busy. We had to make way for cars and mountain rescue vehicles and could see a rescue helicopter using its search light on the surrounding mountains.
The helicopter a few minutes later landed to the excitement of the kids just behind our pitch, stayed for 30 minutes and then departed.
You can only have admiration for the rescue services working in such poor conditions, at that point dark, starting to rain, in practically zero visibility.
Over the next 48 hrs a month's worth of rain fell and on Thursday morning we decided to leave at 7.00 to avoid traffic on the lake rd.
The weather was blowing a gale, the road was effectively a river but passable. After two miles we came to a stop, the lake had effectively swallowed the road, worse still there was a car stranded, hazard lights flashing.
We fought back the wind and rain and checked the car only to find a hotel chef stranded, still in his car, unwilling to get out and asking to raise the alarm. No mobile or internet reception here, unable to turn the van round we reversed, wife outside directing me back making sure we didnt hit a wall or fall into the lake.
Chef was recovered together with others who tried escaping.
So we were stuck, pitched up again and waited it out.
Thankfully the rain became lighter over Thursday night and on Friday we and most of the site escaped that morning as flood levels had receded enough to drive through.
We then struggle to escape the clutches of the flooded Lake District roads trying to avoid road closures, unable to exit south we re tracked north exit via Penrith back to Cambridge 356 miles in 9.5 hrs, a great holiday!
The batteries, the batteries how did they do?
Brilliant, confined to the van from Monday evening untill friday morning with the exception of our aborted escape attempt and one small walk in the rain we were never in danger of running low on power.
With fridge setting on four as we had frozen food, heating more or less on permanently and kids laptops getting well used, in-between Monopoly, Connect 4 and Scotland Yard, lowest battery monitor reading was 48%.
The 48% was the morning of our original attempt to leave, by the time we returned an hour later the engine had put enough charge back in to the batteries for the monitor to read 83%.
So even though the holiday may not of been successful the batteries certainly were.
With the fast recharge capabilities of lithium am confident I could of camped indefinitely without EHU.
Sorry it's a bit long winded.

 

[old-mo]

All the previous post`s regarding Compressor Fridges...

I asked a similar question when we got our PVC....

And most of the above have just confirmed...

Who would be willing to put an ordinary 12v/240v/Gas fridge in for me, down South..????

Any idea`s..???????????

I know it means cutting a hole in the side for the vent and exhaust, Gas supply is near by.. but would sooner have that than go away wondering when the battery`s were going to let me down..

 

[paddymcc]

Thought I would update on how my lithium batteries performed compared to last year with AGM.
Briefly last October we travelled to the Lake District for half-term and experienced three days of horizontal lashings of rain, as a result confined to the van by the end of day two are 2x95ah batteries were practically depleated with 200 Watt's of solar contributing practically nothing.
I should point out we have a compressor fridge and diesel heating. We are not particularly heavy user's, no tv, hair dryers or coffee makers afterall its only a 6m PVC, however we do have teenagers with various devices.
AGM'S were replaced by lithium at RoadPro and off we went back to the Lakes to give them a comparison test.
The lithium batteries had performed perfectly all summer however I had doubts about the comparison as I didn't think I could replicate the poor weather of 2020.
Oh how misguided I was !
We stayed at the NT site at Wasdale head little did we know how the three days would pan out.
The drive along the lakeshore to Wasdale is a single track road with a number of passing places.
We arrived as it was starting to get dark and the road was unusually busy. We had to make way for cars and mountain rescue vehicles and could see a rescue helicopter using its search light on the surrounding mountains.
The helicopter a few minutes later landed to the excitement of the kids just behind our pitch, stayed for 30 minutes and then departed.
You can only have admiration for the rescue services working in such poor conditions, at that point dark, starting to rain, in practically zero visibility.
Over the next 48 hrs a month's worth of rain fell and on Thursday morning we decided to leave at 7.00 to avoid traffic on the lake rd.
The weather was blowing a gale, the road was effectively a river but passable. After two miles we came to a stop, the lake had effectively swallowed the road, worse still there was a car stranded, hazard lights flashing.
We fought back the wind and rain and checked the car only to find a hotel chef stranded, still in his car, unwilling to get out and asking to raise the alarm. No mobile or internet reception here, unable to turn the van round we reversed, wife outside directing me back making sure we didnt hit a wall or fall into the lake.
Chef was recovered together with others who tried escaping.
So we were stuck, pitched up again and waited it out.
Thankfully the rain became lighter over Thursday night and on Friday we and most of the site escaped that morning as flood levels had receded enough to drive through.
We then struggle to escape the clutches of the flooded Lake District roads trying to avoid road closures, unable to exit south we re tracked north exit via Penrith back to Cambridge 356 miles in 9.5 hrs, a great holiday!
The batteries, the batteries how did they do?
Brilliant, confined to the van from Monday evening untill friday morning with the exception of our aborted escape attempt and one small walk in the rain we were never in danger of running low on power.
With fridge setting on four as we had frozen food, heating more or less on permanently and kids laptops getting well used, in-between Monopoly, Connect 4 and Scotland Yard, lowest battery monitor reading was 48%.
The 48% was the morning of our original attempt to leave, by the time we returned an hour later the engine had put enough charge back in to the batteries for the monitor to read 83%.
So even though the holiday may not of been successful the batteries certainly were.
With the fast recharge capabilities of lithium am confident I could of camped indefinitely without EHU.
Sorry it's a bit long winded.

What a trip! I know the road to Wasdale Head well, a great place to spend a few days in nice weather! Mind you in bad weather the hotel is particularly cosy. Glad you survived and thanks for the update on the lithium battery. I'm still waiting for my lead acids to fail after 8 years of use but am ready to swap them for lithium when they give up the ghost.

^{_{Subscribers  do not see these advertisements}}