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Pellet stove battery backup on a budget

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by Griny, Jan 2, 2011.

  1. Griny

    Griny Member

    Joined:
    Oct 27, 2008
    Messages:
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    Loc:
    Western WA
    Pellet stove battery backup on a budget
    What to do when nobody's home and your power goes out and the only thing that heats our house is a pellet stove... My wife and I are gone during the day and we have a African grey parrot in the house that shouldn't get too cold. Here in the northwest we have quite a few power outs during the fall and winter season.
    I do have a generator but have no funds to make that automatic.
    I've done a lot of research lately on power supply's as UPC’s, Inverters, marine inverter chargers and battery backups in general. The one thing that’s most important is that the sine wave has to be pure. Electric motors don’t like modified sine wave's and since pellet stove's have nothing but electric motors usually 2 fans and one auger motor and oh of course the delicate electronic control panel (Lopi manual states that you should plug in your 120v cord in a surge protected outlet) or better a UPS.
    I found a system online which is pretty much what I want “behold the Surefire 502†http://www.medfordfuel.com/Surefire_Stove_Sentry.htm
    One of the problems is that it's ridiculous priced. With a Lopi pellet stove I would have to use the “502†model which is $449 WOOW! Okay did some research on that model and come to find out that its a modified sine wave... Okay for that kind of money it should be ATLEAST pure sine wave right? BS! Dead end here...
    I'm a mechanic at a luxury yacht builder and checked around for an inverter charger with automatic switch for when plugging in a shore cord so like a UPS, cheapest I could find was around $400 pure sine wave of course.
    So dead end again.. Then I got to thinking hmm if I use a APC UPS with a bigger battery? I asked the electrician at my work and he mentioned well the idea is good but what if the small battery charger can't charge the bigger batteries and fries itself? I thought I can't stand it but he's right DAMN! another dead end...
    Then when I was reading up on the forums here someone mentioned butkus.org that guy had done what I initially wanted to do and it worked YEAH! Okay now were cooking!
    I went to Craigslist and Ebay and searched for a UPC which is powerful enough to run my pellet stove (350 watt) I settled for a 980 watt APC SUA1500 bit bigger than I need but I’m sure under long load it won't over heat!
    For $100 + $25 shipping we got it home and I got to work in the mean time I found some cable at work from a restoration job we had and a little piece of richlite for the connector (on the front of the APC) and for the batteries we had a boat in our yard that the owner wanted new batteries and the old ones in my opinion weren’t that bad yet
    So 2 8D batteries some cable connectors zip ties and a APC UPS I’m ready and it works like a charm, when I unplug the 120V the pellet stove keeps just running like nothing happened. I have had it running for 1.5 hours with no problems, Next weekend when I’m home I'll try as long as it goes.

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  2. wingman1776

    wingman1776 New Member

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    Dec 19, 2010
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    Loc:
    central illinois
    if you run your batterys real low it will take serveral days for them to recharge and will put a big load on the built in charger. I have a ups same as yours hooked up to a couple 100 amp hour agm batterys. If i run the low i put the battyers on car charger for while to bring them back up close to full takes a lot of stress on the small built in charger in the ups.
  3. Griny

    Griny Member

    Joined:
    Oct 27, 2008
    Messages:
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    Loc:
    Western WA
    Your absolutely right I was thinking the same thing
    it keeps the batteries at 27volt which is pretty good.
  4. imacman

    imacman Guest

    Griny, I agree w/ what Wingman said about the battery charger if the batteries get real low, but otherwise, that is one sweet setup. Those 6v RV/marine/golfcart batteries in series work great! ;-)
  5. Griny

    Griny Member

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    Did you mean my 6v golfcart batteries? Mine are 2 8 D's the APC requires 24V They are 150lbs a piece! ugh!
  6. imacman

    imacman Guest

    OK, even better! :cheese:
  7. MButkus

    MButkus Member

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    Jersey
    Wet cell batteries will put out hydrogen gas.. a bit flammable. Plus the acid in the batter can be a danger inside a house. I have a setup like this since '95. My batteries are in a warm but vented crawl space. There are those OPTIMA batteries that are completely sealed. The newer sealed car batteries have something in the caps that keep the water from evaporating.
    What I don't see are fuses... any short and batteries can explode or melt any cable and cause a fire.
    You don't need that big of a cable, I used a home 12 gauge electrical cable. You're not starting a car. I have 8+ feet on my cable from the battery to the UPS.
    It's kicked in a number of time for 1/2 hour or more. No heat coming from the cables.
  8. DMZX

    DMZX Member

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    NE. Oregon
    I keep my motorcycle battery on a battery tender in the winter. It trickle charges if the voltage goes down, until the battery is fully charged, then it goes back to sleep.

    Would something like that work?
  9. firewarrior820

    firewarrior820 Feeling the Heat

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    auburn maine
    I wonder what would happen if your belt buckle touched the front of the APC unit ?
  10. ChandlerR

    ChandlerR Minister of Fire

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    Griny...very nice setup! I understand that the parts (cables ect) you used came from work as scrap from other jobs. That said, I think I would put an inline fuse on the cables. I know you can scare one of those up as they're used on boats all the time. I would run the UPS until it shuts off and see how long it takes the on board charger to bring them back up. The charger is limited in the amount of current it puts out so I wouldn't worry about frying it but if you lost power soon after it was used, the batteries may not be charged enough to last very long.

    I'm not sure, but the UPS has a low voltage cut out. I think it is around 12.1 or 12.2 volts. It won't drain the batteries completely.
  11. Griny

    Griny Member

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    Western WA
    Your right I don't need that big of a cable but for longer distances with DC you would like bigger then 12 gauge.
    The fuse is where the old APC batteries would sit is a 50 amp fuse I believe and came with the APC when I bought it.
  12. Griny

    Griny Member

    Joined:
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    Loc:
    Western WA
    Actually I have a recycle bin underneath where I throw my cans, glass etc in and if I would hit that it would arc pretty bad, if fixed this yesterday with putting a piece of plastic in front of that with two holes and two plastic 1/4 20 nuts
  13. turbotech

    turbotech Feeling the Heat

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    I would disconnect the batteries and get or make a proper box to contain them with outside venting. Between the wet batteries being inside of open space out-gasing and all that fuel around them I would consider that very dangerous and unhealthy to breathe.
    Basically, you have a welder right there with the batteries connected like that along with heavy gauge wire.
    I would reduce the wire size and install a fuse right at the batteries. Since the stove requires less than 1kw at startup or about 1000/120 = 8.4 amps then at the 24 v batteries this becomes roughly 8.4 * (120/24) = 42 amps. Include 10% converter inefficiency and it comes out to about 46 amps. That is about what size fuse you would need for the inrush current at startup including the ignitor.

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