UPS function

Discussion in 'Beginner Electronics' started by Procrastinator71, Jun 5, 2008.

  1. Hi,
    I'm using a 700W UPS (localy made) with a 120 Ampere battery to run
    three ceiling fans (150W each), a tube (40W), and my laptop (70W?) and two
    energy savers (18W each) to cover load shedding time which is mostly for one
    hour several times a day. The problem is if all tree fans are running for
    some time, they begin to slow down considerably. Is the battery responsible
    for this or the UPS.
    If I add another battery in parallel will this solve the problem. I intend
    to add another fan to this. Also is there a way to test what is the actual
    strength of the UPS? It is common here to sell UPS that are lower in power
    than what is printed on them.

    Thanks
    Procrastinator71, Jun 5, 2008
    #1
  2. Procrastinator71

    James Sweet Guest

    Michael Kennedy wrote:
    > "William Sommerwerck" <> wrote in message
    > news:...
    >> Running batteries in parallel is a bad idea. Think of what will happen if
    >> their voltages don't match. If you do such a thing, you need to put diodes
    >> in series with each.
    >>

    >
    > Some car batteries are connected in parallel. Especially larger trucks with
    > diesel engines.
    >
    > Mike
    >
    >



    Those normally use a battery isolator which is really just a couple of
    large diodes. Most RVs and larger boats have a setup like that too.
    James Sweet, Jun 5, 2008
    #2
  3. Procrastinator71

    ian field Guest

    "JANA" <> wrote in message
    news:...
    > The 700 W rating is the maximum load that can be used from the UPS
    > without any damage to it, or it with it being over-loaded. Normaly, the
    > maximum load should not exceed about 60% of the maximum capacity of a
    > UPS.
    >
    > In the instruction manual for the UPS, they usually give a chart of how
    > long it will supply power with different loads. The effect of the load
    > may not be exactly linear because the load is being run from an
    > inverter. This inverter itself uses a certain amount of base current to
    > operate. It's efficiency may not be very linear.
    >
    > In theory, a 120 Amp Hour battery should be able to put out 120 Amps for
    > one hour. Normaly, when a battery is under load, when the voltage of
    > the battery has decreased to about 10% below the nominal rating of the
    > battery voltage, the battery is considered weak.


    Most battery manufacturers specify Ah capacity for the 10 hour discharge
    rate - a 120Ah battery loaded at 120A will be discharged in somewhat less
    than 1 hour.
    ian field, Jun 5, 2008
    #3
  4. Procrastinator71

    JosephKK Guest

    On Thu, 5 Jun 2008 20:51:33 +0100, "ian field" <>
    wrote:

    >
    >"JANA" <> wrote in message
    >news:...
    >> The 700 W rating is the maximum load that can be used from the UPS
    >> without any damage to it, or it with it being over-loaded. Normaly, the
    >> maximum load should not exceed about 60% of the maximum capacity of a
    >> UPS.
    >>
    >> In the instruction manual for the UPS, they usually give a chart of how
    >> long it will supply power with different loads. The effect of the load
    >> may not be exactly linear because the load is being run from an
    >> inverter. This inverter itself uses a certain amount of base current to
    >> operate. It's efficiency may not be very linear.
    >>
    >> In theory, a 120 Amp Hour battery should be able to put out 120 Amps for
    >> one hour. Normaly, when a battery is under load, when the voltage of
    >> the battery has decreased to about 10% below the nominal rating of the
    >> battery voltage, the battery is considered weak.

    >
    >Most battery manufacturers specify Ah capacity for the 10 hour discharge
    >rate - a 120Ah battery loaded at 120A will be discharged in somewhat less
    >than 1 hour.
    >


    If they are working to US SAE specifications it is 20 hour discharge.
    JosephKK, Jun 8, 2008
    #4
  5. Procrastinator71

    JosephKK Guest

    On Thu, 5 Jun 2008 14:59:07 -0400, "Michael Kennedy"
    <> wrote:

    >
    >"William Sommerwerck" <> wrote in message
    >news:...
    >> Running batteries in parallel is a bad idea. Think of what will happen if
    >> their voltages don't match. If you do such a thing, you need to put diodes
    >> in series with each.
    >>

    >
    > Some car batteries are connected in parallel. Especially larger trucks with
    >diesel engines.
    >
    >Mike
    >


    Actually the batteries are in series to run the starter motor, and
    isolated otherwise.
    JosephKK, Jun 8, 2008
    #5
  6. Procrastinator71

    Eeyore Guest

    Procrastinator71 wrote:

    > Hi,
    > I'm using a 700W UPS (localy made)


    Just out of interest, of what value is the information "(localy made)" <sic>
    when you don't mention what part of the world you live in ?

    Or is it the 'world' called the USA ?

    Graham
    Eeyore, Nov 13, 2008
    #6
  7. Procrastinator71

    PeterD Guest

    On Thu, 13 Nov 2008 20:08:43 +0000, Eeyore
    <> wrote:

    >
    >
    >Procrastinator71 wrote:
    >
    >> Hi,
    >> I'm using a 700W UPS (localy made)

    >
    >Just out of interest, of what value is the information "(localy made)" <sic>
    >when you don't mention what part of the world you live in ?
    >
    >Or is it the 'world' called the USA ?
    >
    >Graham


    I'd say he made it himself...
    PeterD, Nov 13, 2008
    #7

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