My latest freezer converted to fridge showing VERY good results.

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  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: 48 hour power consumption update

    Here in Nova Scotia, many areas have quite expensive propane. The smaller "20 pound" (of propane) cylinders, standard BBQ sized, are often costing roughly $30. with taxes for a refill or exchange, and many propane fridges suck back a pound a day, so you're looking well over $30 / month to run one. Wish it weren't so.
    Some places are lucky to have reasonable priced propane.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: My latest freezer converted to fridge showing VERY good results.
    No, they don't all run at once! The fridge has priority, so when it wants to run, it powers a relay that disconnects the other two units. When it's not running, the freezer in the basement is next, then finally, if neither of the first two are running, the freezer in the outside shop has it's chance. The "fridge" only runs an average of 5 minutes per hour, so there's lots of time for the other two.

    A neat algorithm. The only question I would have is whether you ever have (or expect to have) a problem with the fridge preempting one of the freezers which is already running? The only down side, other than causing a single short cycle on the freezer, would be if the fridge lets go of the power again quickly enough that the freezer which had been running has not had enough time to bleed down and offload the compressor. If the fridge cycle is too short, you might get a condition where the freezer tries to restart too soon, cannot, and knocks down the inverter.

    (Not at all likely to happen, but I like to propose worst cases to see what would happen.) :-)

    You could add some more logic to your relays so that the fridge also cannot start while either of the freezers are running. I do not expect that the minimum on time of either freezer would ever be short enough to cause a problem for the other. Probably would not be worth the effort.
    SMA SB 3000, old BP panels.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: 48 hour power consumption update
    Here in Nova Scotia, many areas have quite expensive propane. The smaller "20 pound" (of propane) cylinders, standard BBQ sized, are often costing roughly $30. with taxes for a refill or exchange, and many propane fridges suck back a pound a day, so you're looking well over $30 / month to run one. Wish it weren't so.
    Some places are lucky to have reasonable priced propane.

    In my part of northern CA, propane refill of bulk tanks is currently at ~$2.50 / gallon delivered. ($-US/Gal-US)

    Have they pulled the same trick up your way where they reduce the standard fill amount of a 20# cylinder "for safety" but do not reduce the cost per exchange?
    I take my cylinders to the gas station for refilling instead of exchanging for that reason. (I don't feel justified in adding a liquid dispensing system to my 250 gallon tank.)
    SMA SB 3000, old BP panels.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: My latest freezer converted to fridge showing VERY good results.
    inetdog wrote: »
    A neat algorithm. The only question I would have is whether you ever have (or expect to have) a problem with the fridge preempting one of the freezers which is already running? The only down side, other than causing a single short cycle on the freezer, would be if the fridge lets go of the power again quickly enough that the freezer which had been running has not had enough time to bleed down and offload the compressor. If the fridge cycle is too short, you might get a condition where the freezer tries to restart too soon, cannot, and knocks down the inverter.

    (Not at all likely to happen, but I like to propose worst cases to see what would happen.) :-)

    You could add some more logic to your relays so that the fridge also cannot start while either of the freezers are running. I do not expect that the minimum on time of either freezer would ever be short enough to cause a problem for the other. Probably would not be worth the effort.

    Actually, the Fridge regularly interrupts the freezers. I'm lucky the freezer in the basement, with it's added capacitor start, is so strong at starting that it will sometimes restart right away, under full back-pressure, when powered from the inverter (always restarts when on grid) so 5 minutes bleed-down is plenty for it to reliably restart on the inverter. The freezer in the outside shop is older and harder to start, so I have a 10 minute timed delay before it tries to start. Very pleased with how the system works. It's complicated, but gives great satisfaction watching it do it's thing. The only downside is 2 or 3 times a year, on a very cold Winter day when the MX-60 does EQ, it drives the battery voltage high enough to shut down the inverter. About once a year under these conditions, and with a few clouds passing by, the inverter will shut down and restart before the fridge, which had been running, has bled down and after three tries the inverter kicks out, requiring a manual restart. But once or twice a year I can handle. Never happens Spring, Summer or Fall, only happens in Winter. Suppose I could put some kind of restart delay on the inverter, but it's not that big a problem.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: 48 hour power consumption update
    inetdog wrote: »
    In my part of northern CA, propane refill of bulk tanks is currently at ~$2.50 / gallon delivered. ($-US/Gal-US)

    Have they pulled the same trick up your way where they reduce the standard fill amount of a 20# cylinder "for safety" but do not reduce the cost per exchange?
    I take my cylinders to the gas station for refilling instead of exchanging for that reason. (I don't feel justified in adding a liquid dispensing system to my 250 gallon tank.)
    Yeah, roughly 1/3 the $ of propane here. Wow!
    Re the refill amount being reduced, one place I worked, I was licensed (a Provincial Government dictate)to fill up to 60 # cylinders (as well as motorhomes) and we were required by Provincial law to fill only to the 80% point, using weight as the reference, taking into account the tare weight stamped on the cylinder. This was to account for expansion. In one case, one of our regular customers would bring in 60# cylinders for their fishing trawler, but one time they ran out of propane while near another town, so docked there and had one of their cylinders filled there. It was filled alright. (sarcastic) . The guy doing the filling wasn't used to the 60 pounders, or got confused and filled it solid full. Customer transported it to their boat and left port. It was a hot day. Part way out the harbour the overpressure valve let go and in seconds the deck was a cloud of vapor fog which was making it's way below. In pure panic, terrified the running engine would ignite a disaster, they threw the venting cylinder overboard, saved their trawler, and lived to tell us about it.
    By the way, we only charged for the weight difference between pre and post filling, which was law, unlike the "exchange" depots which have a set price regardless of how much may or may not remain in your returned cylinder.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: 48 hour power consumption update
    The guy doing the filling wasn't used to the 60 pounders, or got confused and filled it solid full.

    Can that still happen? Isn't there some sort of overfill protection on modern tanks?
    btw, my propane delivery last month was $1.78 per gallon.

    On the subject of propane fridges, the cheap used RV fridges often require 12 volts DC in order to operate.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: 48 hour power consumption update
    vtmaps wrote: »
    Can that still happen? Isn't there some sort of overfill protection on modern tanks?

    --vtMaps

    Yes, it can still happen. Fortunately, more and more of the new BBQ cylinders do indeed have a float type shutoff that prevents overfilling, but some are still available without that feature, and I have yet to see a larger cylinder with that overfill protection device. I'm not saying they don't exist, just that I haven't seen one yet. And here in NS, cylinders are still lawful to refill until they become 10 years old from when they were manufactured, regardless of when they were purchased, after which they must be discarded, or be re-valved and re certified, which can costs nearly as much as buying a new one.
    Re the propane fridges requiring 12 VDC, that's often to power the CO safety alarm and shutdown. No 12 volts, no CO protection and no propane gets through to run the fridge. The older fridges didn't have CO protection and lives were lost when CO was produced as the result of things like restricted air supply to the flame due to things like mouse nests being built in the burner area during the off season, or carbon buildup in the burner and or heat exchanger/exhaust.
  • Volvo FarmerVolvo Farmer Solar Expert Posts: 209 ✭✭✭✭✭
    Re: 48 hour power consumption update
    Re the propane fridges requiring 12 VDC, that's often to power the CO safety alarm and shutdown. No 12 volts, no CO protection and no propane gets through to run the fridge.

    Maybe propane RV refrigerators are different in Canada. I have never seen one with a built in CO shutdown device. However I have seen a couple dozen Norcolds and Dometics that use 12V for the circuit board and gas controls.
  • RybrenRybren Solar Expert Posts: 351 ✭✭
    Re: 48 hour power consumption update
    Here in Nova Scotia, many areas have quite expensive propane. The smaller "20 pound" (of propane) cylinders, standard BBQ sized, are often costing roughly $30.

    Wayne,

    I don't know whether you have a Costco nearby, but here in Ottawa, they only charge $9.99 to refill a 20-lb tank. The "filling stations" charge $18-$20, and the exchange places charge $25-$35.

    FWIW, up at my camp, a 100-lb tank is $80 delivered (I rent the tank for $20/year and the fellow just exchanges them for me)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: 48 hour power consumption update
    Maybe propane RV refrigerators are different in Canada. I have never seen one with a built in CO shutdown device. However I have seen a couple dozen Norcolds and Dometics that use 12V for the circuit board and gas controls.

    Yep: CO shut-downs on all propane 'friges. I think they removed the regulation since the stupid things didn't work; kept shutting down for no reason.

    Here in B.C. you can predict propane prices by the season: got tourists? Pay more!
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: 48 hour power consumption update
    Rybren wrote: »
    Wayne,

    I don't know whether you have a Costco nearby, but here in Ottawa, they only charge $9.99 to refill a 20-lb tank.

    Yes, we have Costco, but the deal is unfortunately offset by the 6 hour return drive for me. :cry:
  • pdxr13pdxr13 Registered Users Posts: 6
    Re: 48 hour power consumption update
    Some places are lucky to have reasonable priced propane.

    We are lucky to have a $14, 20# tank refill in Portland Oregon, but it may not always be so.

    Energy inflation at the retail level is subject to actual supply shortage price increases as well as the effect of taxes/fees/fines levied by the Federal/State/Metro/County/City/Borough/Neighborhood taxing districts, where as they haven't quite figured out how to tax solar panels (after unlawful subsidy) except as added house value or personal property (sales tax, personal property tax in some places). I'm going to speculate that all energy costs will continue to inflate at the same rate as commodity prices over the past 10 years: ELEVEN PERCENT on-average and annually compounded (real).

    I'm reducing my standard of living to keep the cost of living affordable, because it's unlikely that more income is headed my way.

    Cheers.
  • pdxr13pdxr13 Registered Users Posts: 6
    Re: My latest freezer converted to fridge showing VERY good results.
    BB. wrote: »
    It can be done...

    Even the amount of power used makes an issue in the gasoline vs diesel choices (there seem to be very few choices for less than 8-10kW power diesel gensets vs the 1-2kW gasoline inverter/generators out there).

    -Bill

    If battery bank charging is the only reason to run the engine, and you want small (tiny) Diesel, you can get a Kubota EA or EL 330 to run a large frame alternator. 12/24/48v are commercially available, as well as field-controllers that give a fast charge. You should be able to get about 2000W DC (150A @ 12v?) into the battery bank with one of these tiny engines for about a pint of Diesel fuel per hour. A lot of the advantage is not making AC, then rectifying for high-current DC in a charger, but just making DC from a rotary machine. Not cheap, but doesn't use nasty E10 mandated gasoline.

    Cheers.
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