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substitute car or marine battery in UPS?

Discussion in 'General Electronics' started by Matt, Aug 13, 2005.

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  1. Matt

    Matt Guest

    My Belkin 350 VA UPS has stopped working, and I find its (sealed lead
    acid) battery is dead and won't accept a charge. I can't say that that
    is the only thing wrong with the UPS. The unit is still under warranty.

    First I wonder whether it is practical to try to take advantage of the

    Second I wonder whether I can just use an external automotive or marine
    battery instead of the sealed lead acid battery that came built into the
    unit. If so, do I have to do anything special when using the external
    battery, maybe such as using a separate charger (maybe the UPS's charger
    wouldn't be big enough)?

    The battery in it is like:
  2. A separate charger is not a good idea. The UPS circuitry may have the battery
    floating at an unsafe voltage, and most external chargers will not even be as good
    as the charger in the UPS. (A really good one would probably have a microprocessor
    and measure battery temperature)

    As far as substituting a different battery, that is also not a good idea. The
    sealed lead-acid batteries have different construction than an auto/starting
    battery. They also have slightly different chemistry which calls for a higher
    charging voltage. An auto battery would draw too much current from the charging
    circuitry, would lose water too quickly, and would wear out faster than expected
    if it was cycled.

    So ... I would first try the warranty. If that is no good, then see if you can buy
    an equivalent battery at a reasonable price. You might have good luck with eBay.
    You can often recycle the old battery at an auto parts store. These low cost UPSes
    go through batteries much faster than would a good design, but people keep buying
    them because the limitations are not obvious at the time of sale. Even the mid-
    range UPS (e.g. APC SmartUPS) at $400 and up do not handle the batteries well.
  3. ric

    ric Guest

    Try a motorcycle SLA battery. Something in the 3-4 amp/hr. range.
  4. Conor

    Conor Guest

    Err..thats why they have one.


    If Pac-Man affected us as kids, we'd all be running around in darkened
    rooms, munching magic pills and listening to repetitive electronic

  5. Let the unit charge for a while with nothing plugged in. Then take a low
    power light like a Christmas window candle and plug it in. Look directly at
    the light as you unplug the supply: If the light stays on for just an
    instant then it suggests the circuitry may be good. If you hear a beep (if
    your unit has a beeper when it kicks in, of course) it suggests that the
    circuits worked but the battery only had 'uuuumpf' for a second or two. This
    test is not a guarantee... just a rule of thumb.

    Your battery appears to be a 4.5 Amp/hour unit... what it's charger might
    need to do to maintain a battery rated 10's or 100's times that might be
    more than it can take.

    That said... I have read (when wondering about this same issue) some folks
    who have done what you suggest, though I've not seen long term reports. My
    other thought is not associated to the charger's ability to function, but
    rather what about the associated gasses with marine and auto battery
    charging? Do you really want these in your home or office's atmosphere on
    persistent basis?

    I just recently replaced two 7 AH batteries in my 950 AVR. I picked them up
    at Batteries Plus and was surprised that the bill was only about $32 US
    total. Considering it is a $175 unit, that's a good deal. I saw many
    batteries for much higher on the net, and some for the same with and without
    shipping included, so research well. Batteries Plus is springing up
    everywhere, look here:

    That said... I just snagged a 350 at Staples for $20 bucks on sale last week
    for my son. Back to school time is a great time for UPS, at least in years
    past, so watch for them this Sunday.
  6. John Weiss

    John Weiss Guest

    Why not? I got 2 batteries from them under warranty. They even sent prepaid
    UPS labels for the returns!

    OTOH, I'm not sure I'd buy Belkin again unless the price was WAY right (again);
    their monitoring software was a pain, and 2 batteries did fail prematurely...

    A motorcycle battery may be what you need; it may even fit inside the case.
    OTOH, I wouldn't use a flooded cell battery in the house. Leaking acid and
    escaping hydrogen gas could cause MAJOR problems. You would need a deep-cycle
    marine GelCell or AGM sealed battery. Though the charger might take a long time
    to fully recharge a bigger battery, it would give you a lot longer run time on
    battery power. Also, the charger might not be able to properly detect the state
    of charge of the battery...
  7. Matt

    Matt Guest

    That makes it practical.
  8. Matt

    Matt Guest

    Really? Think about it. Oh yeah, you're a genius.
  9. Matt

    Matt Guest

    They will only send me a new unit, and I have to pay for the return
    shipping of the old one. My application requires a serial port, and the
    new one is USB.
  10. Lyn

    Lyn Guest

    You'll probably discover that the battery is NOT covered under the warranty.
  11. default

    default Guest

    There are sealed lead acid batteries available on the electronics
    surplus market - mail Internet order

    If it were me, I'd get a lawn and garden (tractor) battery. Twice the
    capacity of a motorcycle battery at half the cost - and still small
    enough AH rating so it won't kill the built in charger.

    Sealed battery would still be choice number one - lots safer and
    easier on the floor or furniture.
  12. skylinux

    skylinux Guest

    Will it work, yes. I live in florida and have done it during the last
    hurricane we had in 2004. I was without power for 2 weeks and keept my
    Computer running on UPS and generator.

    You need a deep cycle battery, don't bother with Car or bike batteries,
    they can't handle it.
    PLEASE CONSIDER, your UPS is not designed for hours+ operations that you
    will get from a large deep cycle battery. You must add cooling fan(s)
    and heatsinks here to cool down components that get too hot.

    I did not try charging the battery using the UPS circtuit. I used a
    proper charger to charge the battery, then connected it and used it.

    The UPS I used it on was a APC 1100VA

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