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Thread: is it possible to parallel 2 or more UPS output?

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    Default is it possible to parallel 2 or more UPS output?

    target:
    get 2 hour back up time

    problem:
    APC smart 1000va only 45 minutes
    APC smart 3000va to expensive and when i check the manual looks like apc 3000 got less feature than 1000va

    question:
    is it possible to combine 2 ups output into 1 output?
    so i could buy another 1000va ups

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    Default

    Last edited by Testakraze; 11-26-2013 at 02:02 AM.

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    So you mean daisy-chain two (or more) UPSs, so that they run until exhaustion one by one, starting from the one that's closest to the wall socket?

    In theory it should work, but even with the batteries being meant for deep cycle duty, they won't keep their capacity for long if you fully discharge them regularly...

    Perhaps ghetto-modding the UPS you already have with more/bigger batteries instead is an acceptable solution? To avoid full discharge, I mean. Would increase charge-to-full time, though.
    Careful what you wish for... You just might get it.

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    Default

    just found 1 article (placed to 2nd post)

    never know the fully discharge could reduce the batteries durability
    Thx McSteel

    i will try to search some mods
    but since i got no electronics skill
    i will ask other expert, dunno the cost and risk

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    Running UPSs parallel is asking for trouble. Daisy-chaining is definitely less troublesome, since you can only ever damage batteries that way. Parallel connection has the potential to kill one of the devices in rare cases, which is much more costly.

    By ghetto-modding I meant connecting more/bigger batteries that will reside outside of the device. This could have a potential minor health impact, if the batteries used are not fully sealed, since it would mean breathing in corrosive/toxic fumes. Very diluted, but still...

    You could look up some 32+ Ah batteries, and hook them up, prolonging the operation time. They need to be deep-cycle optimized and sealed, ideally using gel instead of the traditional liquid for electrolyte. Those can be a bit pricey, but are worth it if you really need long runtime.

    It's just a matter of extending the battery connection (using quality cables and connectors) for the UPS to outside the unit itself, and hooking up your overgrown batteries. In theory, you could stack up 100s of Ah of capacity, but like I said, the charging speed and charge current are optimized for the original battery pack, so it could take a long time to recharge.

    If I'm not mistaken, your current UPS uses two 12V, 12Ah batteries in series, resulting in 24V, 12Ah. You need to be careful to respect the connection topology, by either using a natively 24V battery, or two 12V ones connected in series. Other combinations are possible, such as using 4 batteries, two in parallel connected in series with another two parallel ones, for example.

    Using two of these in series, for example, you would extend your battery runtime by 2,6 times. So if you had 45 minutes, you'd now go up to 2 hours at the same load level. Charge time would go up by about the same factor, perhaps a little bit more.

    Of course, I'm not recommending those exact batteries, but they're a good reference to what you're looking for (sealed, gel, deep cycle, high capacity).

    Be advised, some UPS models will report a battery problem, because they'll detect the battery voltage is climbing too slowly (since they need longer to charge). You should, naturally, ignore such warnings if you do mod your device.
    Careful what you wish for... You just might get it.

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    Default

    cannot use naked external batteries
    the place could be reached by children (unfortunately)

    i found one mod link
    http://www.repeater-builder.com/back...00-xl-mod.html

    instead using 12AH
    the UPS use 18AH

    still not wise decision, price wise
    because 2x 1000 mod 2x 18AH
    same price with one 3000va (using 4x 18AH)

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    You could, in theory, use a wooden housing for the external batteries, like a lockable box or something... But that's probably taking things too far.

    What can I say, you're gonna have to go with a custom-made UPS or an industrial one, if you want 2+ hours of load runtime...
    Careful what you wish for... You just might get it.

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    yup
    i will using external batteries

    still something wrong with those external batteries
    why adding external batteries could increase more than the internal batteries back up time while both external and internal got same batteries

    for example
    apc bz1500pbi
    http://www.apc.com/products/resource...u=BZ1500PBI-BR
    load 200 watt 23 minutes
    with external batteries 88 minutes

    apc 1000xli
    http://www.apc.com/products/resource...total_watts=50
    200watt load 88 minutes
    with external bateries 324 minutes

    sua3000 (theoretically with same batteries like 1000xli + ext batteries)
    200watt 167 minutes

    those external batteries really beat the internal batteries
    i don't understand is it true or just marketing gimmicks

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    Default Bettet to add batteries

    If your UPS has a fan, meaning that it doesn't depend on running out of power before it heats up dangerously, then you can very easily add external deep-cycle batteries. I've done this with a lot of 1500-2500 VA UPSes with considerable success. Just find a matching connector, and use seriously thick wire.

    I like to use non-sealed lead-acid batteries and check on them twice a year, but you
    can use sealed if you don't think you're up to the maintenance.

    (Another good trick is to do a couple of hours of equalizing overcharge at the same time.
    A typical cheap battery charger/car starter can do an overcharge if you put the one switch on the "10A charge" setting, and the other on the "car start" setting, which disables the fully-charged detector.

    Check that water isn't too low, then equalize (which will cause bubbling, so you don't want the water too full), then top up the water.

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    Default

    won't use non sealed batteries
    worry about health issue

    still i hate those fan on the UPS, in the past i replace up to 5 fan or the UPS will overheat and alarm on

    prefer metal casing without fan or APC which using the fan for back up mode only

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