Vexed by inverters

DeveakDeveak Posts: 38Solar Expert ✭✭
So my mothers el cheapo modified inverter died, it was a 1200 watt whistler pro. It was already sent in to the manufacturer to be fixed once, made a horrible noise and is completely dead. I doubt they will fix it again so in the market for something quality. The inverters job for the last 1.5 years it lasted was to run a 5 cubic foot chest freezer thats about 1.7 amps. I want to step up to something that will last and is pure sine. I am really not sure what to get without breaking the bank. Is the exceltech xp 2000 really that good? I know its an old brand and they have life time repairs for 100 bucks. Is there a cheaper alternative that still has that quality? Trying to convince my mother to drop AC motor appliances all together and get a dc freezer. Seems a waste to over size inverters just to run something because of inrush. Also i have yet to find a freezer or fridge thats actually insulated. The 1100 model is a LOT cheaper but has no surge. Mostly looking for exceltech feedback and inverter suggestions.

Comments

  • BB.BB. Posts: 27,689Super Moderators admin
    Deveak,

    You have pretty much summarized the "necessary evil" of refrigerators/freezers and AC inverters.

    DC refrigerators/freezers can be OK... But they tend to be horribly expensive in their own right, and sometimes difficult to find somebody to repair.

    For a small freezer, yea, you are usually looking for a very goo 1,000 Watt inverter, or a generic 1,200 to 1,500 Watt inverter to "guarantee" it has enough surge capacity.

    In times past, people have said pretty nice things about the Xantrex 1,800 Watt ProSine Series (I think it is "pro sine")--May be an OK solution at less costs.

    Is she using a 12 volt or 24 volt battery bank?

    If this is a simple "chest freezer" with no auto defrost/electronic thermostat/etc. -- One of the nice thing about the expensive Outback and other inverters is their "search mode".

    A standard mid-size inverter may take 10-20 Watts just "turned on" -- A significant load. In stand by, the inverter only turns on for a couple cycles every second (6 watt or less standby load)--When there is an AC load > ~6 watts or so, then the inverter turns on 100%.

    Is this an off grid application? Or just battery backup for poor utility power?

    Many times, once you get a freezer/refrigerator on AC Inverter Power, the system is large enough to supply AC LED ligiting, TV, lapptop, etc. loads. Usually easier to maintain / buy replacement 120/230 VAC appliances vs their 12/24 VDC counter parts.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • DeveakDeveak Posts: 38Solar Expert ✭✭
    Its a 12 off grid system, we are upgrading currently. Going to get a midnight classic and new batteries. We currently have 725 watts of solar, two pwm morningstar 30 amp charge controllers, 1000 ah of batteries but they had to be refurbished, around 700 now. The only inverter we have running is our 5000 watt chicago electric modified we got at harbor freight. I did not design the system but its a real mess. I had to remove a controller because it was wired wrong and would over charge the batteries. The whole thing needs redone. The new batteries are some RE batteries from SBS industries. We plan on getting a 14.7 cubic foot sundanzer. You mention hard to repair, are they notoriously unreliable or what?
    For myself i plan on building a peltier fridge/freezer. I know they are not efficient but i plan on off setting that with LOADS of insulation. 6-8 inches of the highest R value i can find. Insulation is cheaper than panels and batteries, i could build the whole thing for less than 200. Thats for me though. I know a dc freezer would be better off but if i can get it NEAR a dc freezers daily kw i would consider it a better option.
  • westbranchwestbranch Posts: 5,084Solar Expert ✭✭✭✭
    Have a look at the newest offerings of standard fridges, I found a Westinghouse model at Sears, on the floor, that is 'rated' at less than 1 Kwh per day over a year (341Kwh/yr). there are others out there, know that there are only about 3 major US fridge makers now, even though the brands are still used, usually made to a price point... Main benefit is they are usually fixable in a day and parts are readily available...pay less on the fridge and add more panels...
     
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  • DeveakDeveak Posts: 38Solar Expert ✭✭
    problem with more panels is eventually i need to either step up to 24 volts, which means a narrower market of inverters and i can no longer use my own inverters or buy more charge controllers. There is a big gap in cost, a giant hurdle that limits how far you go. 12 volts is hard to push beyond 1000 watts. I might as well just get the sundanzer and a efficient small inverter and just use less.
  • BB.BB. Posts: 27,689Super Moderators admin
    I am not off grid and have not used any of the DC refrigerators... Today's 120 VAC energy star appliances are pretty close in power usage to the DC versions--And if defrosting is an issue--The frost free is nice.

    My suggestion is to do some paper designs and cost out the options (12/24 VDC vs 120 VAC system+appliances).

    If you are growing the AC/DC power needs much above 1,200 Watts, I would suggest 24 volt system. In general, higher power 12 VDC systems can be a pain.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Posts: 4,662Solar Expert ✭✭✭✭
    The Exeltech's are reportedly pretty bomb proof, I believe they have a peak rating of double the label I'm sure a 1100 watt unit would run the freezer and I suspect a 600 watt might! I am a bit surprised at they high wattage of a 5 cubic foot freezer in use, They typically use 1/2 Kwh a day or less total for modern one. I've been looking at purchasing one. I do own an Exeltech 1100 and have used it with a 1200 watt chainsaw, of course it has no startup resistance like a compressor. we have a member who has run a fridge off a 300 watt inverter, with a bit of setup, I think a capacitor start of his own design?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • waynefromnscanadawaynefromnscanada Posts: 3,009Solar Expert ✭✭✭✭
    Personally I wouldn't buy a DC fridge. Extremely expensive compared to off the shelf and PV is now very cheap compared to a few years ago. Inverters? I need one anyway.
    Standard Energy Star off the shelf fridge - if it quits, replace it.
    DC fridge, if it quits - - re-finance your house.
    But that's just my opinion. Been running 2 freezers and a freezer converted to fridge for a lot of years.
  • animattanimatt Posts: 294Solar Expert ✭✭✭
    Buy an inverter refridgerator. I got a medium size one. Can not remember exact size. Probably around 12cf . Rated at 275kwh yearly. It runs off a morningstar suresine. I do not think there is a more reputable inverter around. This all depends on the market you were in.

    I picked inverter refridgerator up for around $500.

    Something to think about. MY Inverter refridgerator(SAMSUNG) has no surges.

    Morningstar suresine is a 300w running / 600w peak inverter with I believe 6 watt of self consumption.
  • Graham ParkinsonGraham Parkinson Posts: 28Registered Users ✭✭
    BB

    Do typical modern fridges work ok with inverters with search mode? Or will fridges default back to defrost mode or other startup cycles when in search mode? We're wondering about the standby draw of a big inverter running a fridge and are looking around for a low draw 120VAC 18 Cu Ft. fridge that behaves well with search mode. The alternative is a separate circuit with a smaller low loss inverter on 24/7 for the fridge.
  • BB.BB. Posts: 27,689Super Moderators admin
    The answer is "its complicated"...

    Me being a cheap skate--The refrigerators I have purchased have something like a 12 hour electric clock work timer that does a defrost ~1-2 hours out of every 12 hours. If your refrigerator runs at 50% duty cycle, then the defrost cycle is once every 24 hours.

    I believe years ago, Niel tested his refrigerator with defrost turned off, and after about 24 hours, the efficiency started to fall off (the evaporator coil starts to ice up and block air flow).

    And there are refrigerators with electronic defrost timers that have been known to go into "defrost" when AC mains power is restored.

    If you can find a simple manual defrost refrigerator, then a search mode AC inverter would probably work fine...

    You can probably hack up a simple (non-computerized refrigerator) to do what you need--Or even accept a once in ~24 hour defrost timer (especially in drier areas--less humidity, less icing).

    And then there is the Chest Freezer to Refrigerator conversion--Can be very efficient (some have been reported to run an ~8-10 cuft conversion on 250 WH per day). You modify to catch the condensation and divert to a drain/drain tube (no defrosting). Found that running a "good" electronic thermostat very near freezing, and the relatively high humidity--Food and Vegetables last much better.

    Down side, not many spouses like moving food/baskets around for access in a chest freezer.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • DeveakDeveak Posts: 38Solar Expert ✭✭
    I did find a minifridge thats "acceptable."
    It has no freezer but its 226 kwh a year. I know i can go larger and per cubic foot it gets better but this is the easiest on the solar and still a decent size. I think i might be able to run it on a 750 watt inverter as well.
    http://enervee.com/refrigerators/131319238_daewoo-4.4-cu.-ft.-compact-refrigerator-white
    "hack up" what do you mean? would it be possible to remove all the parts and put it in a real insulated case? Cause that sounds a lot better.
  • BB.BB. Posts: 27,689Super Moderators admin
    No--I intended to say that you could pull the timer wires and run them from a very small AC inverter (save power), or program a programmable relay to do the defrosting on your schedule, etc...

    One "big problem" with standard refrigeration compressors is that the mass produced ones assume connection to the Utility Power, and there is very large surge current available. They can build the pumps cheaper because of this.

    At this point, there are not a lot of low starting surge compressors out there. However, some folks here have used Hard Start Kits, or even went off the deep end and made there own Hard Start Module (voltage sensing relay, auto wired transformer, played with motor start capacity values, etc.). But for most people, it usually is not something that they have the knowledge or can take the time (and sometimes the money) to experiment.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • DeveakDeveak Posts: 38Solar Expert ✭✭
    I was under the impression that hard start kits only reduced the length of time it surges and not the amount. That can still be useful for preserving the motor and inverter as well as helping with cheaper short surge rated inverters.
  • BB.BB. Posts: 27,689Super Moderators admin
    I don't know--In the end, probably would need to test it on "your system" to see if it works for you.

    In some cases, a length of "cheap" extension cord adds enough resistance to drop the peak surge current, but still allow enough to start the motor.

    Although, compressors (and refrigeration compressors) are usually very difficult to start (there are unloading valves and other options--But can be a very application specific solution).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • DeveakDeveak Posts: 38Solar Expert ✭✭
    Just want to give a general update. I did buy the exeltech xps 2000 from NAWS. So far it has performed flawlessly in output and what i can handle....however. This will get me banned but I have to say it. NAWS has severely burned me and will no longer get any of my business or anyone I know. I bought it based off information they had on the page. Mainly the high voltage cut off. They claim 16.5 volts in the literature. Well its actually 15 volts and its wrong and still wrong even after I told them. They pretty much brushed me under the rug and sent me after the manufacturer who cant really do anything, said no refunds since I used it and pretty much ignored me. So i spent near 1800 bucks on an inverter I cant use when i equalize of even if the batteries get a hint of cold because of temperature compensation. My batteries equalize at 15.9 volts, bulk at 14.8. Really steamed me. I might end up selling it but i'm not sure yet. Its a good inverter but in no way is it designed or useful in a solar application. A back up UPS system at best and pretty much lower voltage batteries like agms or gel cell.
  • marxmanmarxman Posts: 3Registered Users
    Contact your credit card company as you would be surprised what they can do for you.

    2008 Class C Four Winds Chateau Sport 28A

  • DeveakDeveak Posts: 38Solar Expert ✭✭
    A little late had, it for about 5-6 months. Also a debit card. On the hunt for another inverter. Probably could sell the exeltech.
  • DeveakDeveak Posts: 38Solar Expert ✭✭
    A little late had, it for about 5-6 months. Also a debit card. On the hunt for another inverter. Probably could sell the exeltech.
  • mike95490mike95490 Posts: 7,794Solar Expert ✭✭✭✭
    peltier coolers.   Can only manage 40°F difference from hot to cold side.  And you have gobs of heat to get rid of.  Very inefficient.  You will have to stack about 4 units in a 1:3 setup to get freezing temps, and then you will have several hundred watts of heat to dump somewhere.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • rickrick Posts: 122Administrators admin
    Deveak said:
    Just want to give a general update. I did buy the exeltech xps 2000 from NAWS. So far it has performed flawlessly in output and what i can handle....however. This will get me banned but I have to say it. NAWS has severely burned me and will no longer get any of my business or anyone I know. I bought it based off information they had on the page. Mainly the high voltage cut off. They claim 16.5 volts in the literature. Well its actually 15 volts and its wrong and still wrong even after I told them. They pretty much brushed me under the rug and sent me after the manufacturer who cant really do anything, said no refunds since I used it and pretty much ignored me. So i spent near 1800 bucks on an inverter I cant use when i equalize of even if the batteries get a hint of cold because of temperature compensation. My batteries equalize at 15.9 volts, bulk at 14.8. Really steamed me. I might end up selling it but i'm not sure yet. Its a good inverter but in no way is it designed or useful in a solar application. A back up UPS system at best and pretty much lower voltage batteries like agms or gel cell.
    Deveak,

    I want to apologize for any trouble you've experienced with your order. This is the first time I've heard about it. We only sold 2 of the XP-2000-12 inverters in the last year and we called both customers. Neither of them were you. We also searched for your email address and couldn't find any orders associated with it. Nobody in our shop recalls talking to you either. So we went ahead and called Exeltech and they said they would definitely replace your inverter if it's not meeting the manufacturer's specifications. They told us that you just need to give them a call and they will be happy to assist you. If you would, can you send me a private message with your contact info so that we can look up your order in our system? If you need any assistance in dealing with Exeltech, please let us know. If it's easier for you, feel free to email me personally at [email protected]

    Rick
    Website administrator for Northern Arizona Wind & Sun
  • DeveakDeveak Posts: 38Solar Expert ✭✭
    Just want to add, NAWS contacted me and fixed my issue. Exeltech called and is sending me a replacement unit and swapping the old one out. The new unit has a higher cut off voltage. Thanks NAWS!
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