12v compressor fridge

Discussion in 'Fridges & Ovens' started by Pete5996, Aug 1, 2018.

  1. Pete5996

    Pete5996 Funster

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    I'm on the verge of pushing the button on a Vitrifrigo 12v compressor fridge to replace my existing 3-way Dometic RM7361, having run out of patience with its reliability. My MH is a 2009 Cheyenne, with 2 x Varta LFD90 batteries and a 100w solar panel. The MH PSU is a Sargent EC325. The nominal current draw of the fridge is 2.8A. I tend to spend most of my times in sunnier climes so I'm content with the charging situation.

    I have the option of buying a multivoltage AC converter/controller, which would automatically supply power from the mains when on an EHU, at a much-reduced price at the same time as purchasing the fridge.

    Now, I'm happy to accept that the fridge will run on the batteries, topped up by the solar panel when off-grid, and that the EC325 will provide the 12v to the fridge and charge the batteries when on EHU. The EC325 progressively reduces the charge current to the batteries as other leisure loads increase. I'm wondering if the constant draw from the batteries could lead to their earlier deterioration and whether giving them a 'breather' from time to time by using the AC supply when on EHU would be worthwhile?

    Your thoughts would be appreciated, ta....
     
  2. TeeMyob

    TeeMyob Funster

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    Hi,

    If you have good batteries and solar, I do not see any issue.

    I run a small 240v freezer from a Victron 2Kw inverter. We only have a 110ah alternator but 200w of solar. The freezer is in additon to our Dometic fridge with freezer box.

    The Batteries are Trojan Gel

    What model of multivoltage AC controller are you intending to use please?

    Trevor.
     
  3. Pete5996

    Pete5996 Funster

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  4. Neckender

    Neckender Funster

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    I can’t help with your question but our van is fitted with a Thetford compressor fridge, 2 Varta AGM 95 AH batteries, 200 watt of solar.
    I also run a CPAP machine with humidifier through the night, some 12 volt tv and charge tooth brushes, phone, iPad and also run a dab radio and in the last 18 months we have been fine for 12 volt power.

    John.
     
  5. andy63

    andy63 Funster

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    Cant see why you would need the additional ac power supply for the fridge as long as the van psu is capable of supplying the fridge current..
    I suspect the 2.8a is an average.. my small 65l compressor fridge can draw 3 to 4 amps when running..
    My 100w pannel just about copes with my small compressor fridge in good weather... which is when the fridge is working at its hardest anyway.. when the suns not shining the fridge is a large drain on the leisure batteries unless im on hook up
    Andy
     
  6. Minxy Girl

    Minxy Girl Funster Life Member

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    I'd suggest looking at increasing your solar input as 100w is a bit low for keeping the batteries topped up for running an electric fridge when not on EHU.
     
  7. TeeMyob

    TeeMyob Funster

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  8. Nasher

    Nasher Funster

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    I have a Waeco CRX-50 12v fridge

    I have a 110 Ah leisure battery and no solar

    With a bit of planning, l manage 3 days (2 nights) off grid, which includes lights, water pump, small tv & a bit of power for the diesel cooker

    I had the option of a mains adaptor for the fridge, but the on board charger is sufficient to recharge the battery & run the fridge, so i didn't bother adding another thing to go wrong!

    One thing i was advised is to wire the fridge directly to the leisure battery (fused obviously) as many of the 'control panels' can give power loss & the Waeco fridges will run up to 24 volts, so no additional voltage regulation is required.

    It might be worth you looking at the Waeco range..
     
  9. chaser

    chaser Funster

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    we also have one of these , with two 100 a batterys and a 100w solar and it never runs the batterys down, they are never less than full on the panel
     
  10. SandraL

    SandraL Funster

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    The ac dc controller seems to be a clever bit of kit, not just a dc charger.
    It has facility to disconnect fridge if battery voltage goes too low . After a quick glance it appears highest voltage to cut out is 11.3v which for me would be too low.
    For me to buy would mean more research than just a quick glance at spec sheet.
     
  11. DBK

    DBK Funster

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    If you are on EHU the fridge won't really take any power out of the batteries, it will essentially be run by the 12 volt charging system.

    We use a compressor coolbox to supplement our small gas fridge and 100W solar was not enough so I added a second panel but if you only use the MH in bright sunshine then you may get away with it. I suggest give it a go and see how you get on. :)
     
  12. Nasher

    Nasher Funster

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    The Waeco fridge cuts out on low voltage - but I believe it's 9.5v - which, in my opinion is too low
     
  13. chaser

    chaser Funster

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    ours has never been below 12.3 with no hookup, just 100w solar, but do move every couple of days.
     
  14. scotjimland

    scotjimland Funster Life Member

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    agree 100% ..

    at that voltage the battery may well be permanently damaged.. or at least it's life shortened..

    voltage should never be below 12v.. it seems odd that Waeco have set the cutout so low.. 11.5v would have been more prudent.. my inverter would alarm at 11.5v
     
  15. Pete5996

    Pete5996 Funster

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    Many thanks for all the responses - plenty of food for thought there. On balance it would seem that the 12V only option will be sufficient, so I'll settle for that.

    The EC325 PSU is a little different from other PSUs as it has a built-in solar controller which can take a maximum of 100W of solar panel. I think I'll probably 'suck it and see' for a while before I go to the expense of extra panels and a separate solar controller. However, I don't know whether it's possible to have a separate solar controller with the charging system mentioned below.

    The EC325 also different inasmuch as it has an 'intelligent' charging system which increases the voltage to the batteries to up to 18V and their recommendation is to not connect anything directly to the batteries as this may interfere with or damage the charging system, so direct connection to the batteries is not an option.
    ec325.JPG

    The 12V supply for the hab area is regulated at the PSU to provide up to 25A for all services, with just one feed for a permanent supply, currently fused at 5A for the radio and fridge circuit. I emailed Sargent a couple of days ago to confirm that using this feed, uprated to 15A, would be suitable for the fridge supply but I haven't yet had an answer.

    The head-scratching continues...
     
  16. mitzimad

    mitzimad Funster

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  17. maxi77

    maxi77 Funster

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    Like so many you dont give us sll the facts. What is your other battery load. If you add the fridge load to your other load then compare it with the charger output the answer as to whether you need an additional power source. I would suggest that another 100watt of solar would be good. If your visits to sunnier climes are in winter i would suggest 200 watts is a minimum as you can get several cloudy days in a row.
     
  18. Pete5996

    Pete5996 Funster

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    Apologies - I was hoping to avoid typing 'War and Peace - Part Two' in case readers got bored....:)

    The answer is not a lot, normally. LED lighting all round, drawing perhaps 2A or so on a dark evening; possibly 22W + 13W from the 12V TV and Humax box - say 3A; usual battery charging for phone, tablet etc. I'd not expect to be drawing more than 10A at any one time, so with 15A available out of the total PSU output of 25A max, I think you've pointed me towards the answer.

    Re the solar, I'll refer you to the answer I gave Minxy Girl earlier(y)
     
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  19. rod_vw

    rod_vw Funster

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    I use a Waeco CRX65 (64 litre) in a LWB High-roof VW T6 with 100W Solar and two 90Ah Banner Energy Bull Leisure batteries, all lighting is LED.

    Due to a modern smart alternator the charge regime is via a RING RSCDC30 which is also a MPPT solar controller. Additional is a simple PMS3V 240v distribution + 15A 12v charger + 12dc distribution unit. {Anyone who may have had problems with an early version of this RING RSCDC30 should speak to RING technical support as it may need a software update}.

    We have just returned from 45 days in Europe with ambient daytime temperatures in the thirties and have had no problem keeping the fridge cool & freezer box frozen. My only addition to the basic fridge set-up is a pair of small computer fans that assist the Waeco fan in two speed operation controlled by a couple of thermal switches (and resistor pack) mounted on the fridge plumbing. The new CRX65 has a much more professional heat exchanger than the older CR65 and has an airflow that is left to right across the rear of the unit. In my case the additional fans assist this airflow in one side of the cabinet and out the other.

    Rod
     
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  20. csd4t

    csd4t Funster

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    My set up is 100w sp, EC325, Waeco 80l (I think) and two 80ah batteries last weekend at FFF rally batteries were showing 11.5v after 1.5 days. Outside temp was high 20's fridge alone was pulling 4.5 amps and solar in bright sunshine was only putting in 1.5-2a. A couple of hours on the generator sorted it out for the rest of the weekend but I think my batteries are on their way out. The poor performance could also be related to temperature.
     

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