how to remove the surge protection from a UPS ?

Discussion in 'General Electronics Chat' started by evolutionX, Aug 22, 2008.

  1. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    Hi,
    I have two 400W flashes and I want to use them with a UPS for on location photography where there is no power source. The problem is that the UPS has a protection surge which is triggered when I power on the flashes, even if the UPS is connected to 220V power source. So I want to remove the power surge protection from UPS, is this possible? and how?

    Thanks !
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Sounds like they are simply too much of a load for your UPS.

    Get a larger UPS, or smaller flashes.

    If you did manage to remove the surge protection, you would likely fry the UPS.
     
  3. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    the UPS is rated 1200VA/730W, it should handle a 400Ws flash, there are 2400Ws flashes powered from a 12V/15A battery with inverter, but they are too expensive.
    The UPS have an overload indicator which is not triggered !, if the flashes would be too powerful then I should get the overload error, not the surge protection.
    If I plug in the UPS an 1000W consumer then I get OVER LOAD on the UPS display, with one flash connected I get FAULT which means power surge.
    ....or maybe I should delay the power draw of the flashes, someone told me to use a resistor for this, but I'm not sure how?
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    It sounds like an instantaneous draw issue, for a millisecond or two they are drawing some serious current, that or there is some kind of voltage backlash from the flashes. What SgtW said is probably correct, you will fry your UPS if you remove its internal protections, they are there for a reason and are doing their job.

    What are the makes/models of the flashes?
     
  5. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    the flashes are Elinchrom D Lite 4, they charge to full power in 1,3 seconds
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Not with that UPS, they don't!

    Attempting to run them with a current-limiting resistor may damage them, as they were designed to operate from a certain voltage.

    Pro photogear isn't cheap. By comparison, UPS devices are dirt cheap.

    Instead of a UPS, you might investigate heavy-duty AC inverters. You could power one from your vehicle's electrical system. But, even a 400VA inverter draws 30A current from a 12v battery.
     
  7. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    I have a big AC inverter and I can power my 800W smoke machine without any problem, but when I connect a flash it powers on, but it does not charge.
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Then something's going on with your flash units.

    They're looking like a dead short to your UPS and your inverter.

    Try connecting them in series with several 100w light bulbs. The bulbs will glow during the initial charge, but when the flash charge gets built up the bulbs will dim and go out.
     
  9. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    But when I connect the flashes directly to 220V power they work without any problem.
    I will try that, but what do you mean "several 100w light bulbs" ? how many? more than 3 will over load the ups.
     
  10. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    The light bulbs are in series with the flash units. They will only light up if the flash units are trying to draw a lot of power. The light bulbs will dim or go out once the flash units are charged.

    If they light up for any length of time, it means they are taking the power your flash units were taking. Consider the implications.
     
  11. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    I don't understand the problem.

    Why do you need the UPS at all?
     
  12. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    And how many bulbs do I need to connect ?
     
  13. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    To use them on location where there is no 220V power source and use the UPS as a portable battery.
     
  14. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Figure around 600W of bulbs, say 6 100W units (or adjust according to bulb wattage) in parallel TO EACH OTHER and in series with the flash units. Again, if they glow for a long length of time you probably need to get back with us, there may be something else going on.

    Light bulbs have a neat property, their cold resistance is much lower than their hot resistance, so if something else is taking the power they will dim out. But they will not allow too much current to exit the UPS.
     
  15. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    You are still not telling us the whole story.

    UPS units are not designed to be portable mains replacements.

    what kit do do have?
    What kit do you need to connect simultaneously?

    Normally it is cheaper to use a portable generator rather than accumulator cells. It is also more reliable and capable of longer continuous operation.

    You seem to be describing some serious kit so you need to employ a serious solution.

    If you are doing this in the UK or Europe you also need to be careful of the electrical regulations for portable appliances.
     
  16. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    I told you, I have two Elinchrom D Lite 4 flashes (400Ws each), I want a temporary solution, at least if I could use the car AC inverter, but the same thing happens with that, the flashes draws too much instant power.
    Professional portable flashes are powered from 12V batteries with inverters, I can't afford yet to spend $5000 on two elinchrom battery powered flashes.
    A generator is not a good solution, it makes too much noise, its' big, heavy and produces smoke
    This is how a portable battery powered flash looks like http://www.pictureline.com/products/13634/Elinchrom_Ranger_RX_To_Go_Kit/
     
  17. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    I am sorry if you can't hold a reasonable discussion to get to a solution.

    The reason I asked is because 800watts at 12 volts is nearly 70 amps. At his rate an average 40 amp hour car battery will be operationally discharged within 10 minutes and discharged beyond recovery within half an hour.

    You didn't answer the questions I asked so we still don't know what you are trying to connect to what, or the extent of your electrical knowledge.

    Flash units are normally specified in Joules or not in watts, which is a meaningless term for flash units.

    I have serious reservations about the adequacy of your primary source.
     
  18. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    flashes are in Watts/second, they don't draw that much current, just look at the link above, a 2400Watt/second flash can fire 250 full power flashes from a 12V/15A battery.
    The flashes have a capacitor which charges with many thousands of volts, they don't draw continous power.
    My flashes are 400Watt/second
     
  19. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Not quite.

    Flashes are in watt-seconds, not watts per second.
    since watts are joules per second, watt-seconds equals joules, which is what I said.

    I know exactly how portable flash units work, I have some of these myself. I also have considerable experience of site lighting, both flash and illumination, having spent many a (happy??) night using these and lugging heavy batteries about.

    I would first like to check that your battery is actually man enough for the charging job.
    The battery voltage falls with increasing curent and will be below 10 volts at 70 amps discharge, even for short periods.

    This voltage may not be enough to drive your invertor properly. If this is the case we are looking for the most practicable solution in your case. This may involve modification to your invertor or your flash unit or a bigger batery or more batteries or a genny.

    Don't dismiss a genny, they can be sited quite a distance away, with power supplied through an extension. They don't give up in the cold weather and have many other attractions. You would need some form of generator to recharge your batteries anyway.
    If you are using the one in the vehicle, what is the difference?

    Your energy chain is already pretty inefficient; I don't think introducing extra inefficiency in the form of light bulbs will really help.
     
    Last edited: Aug 23, 2008
  20. evolutionX

    Thread Starter Active Member

    Aug 22, 2008
    31
    0
    I know that the best solution is to get portable flash systems, but right now this is what I have. I also have 4 Canon 580EX flashes but they are too weak in daylight.
    The car invertor should work when the engine is running, but it is possible that the inverter does not produce real sine wave and that's why the flashes are not charging.
     
Loading...