Munro Posted December 3, 2015 Share Posted December 3, 2015 Morning All, I need to find a way of getting power to an 80 lamp festoon (or fluorescent strips) which are situated on a stage flat, without trailing a cable across the performance space. The difficulty here being that the flats are on casters and are moved around a large space during the performance. In an ideal world, I'd also like to have some form of control over said lighting. I've considered flying a cable in from above but the nature of the movement would make this impossible. Current thoughts are some form of battery power (which I have absolutely no clue about) or potentially having a cable and plug which is worked into the performance. I was hoping for some form of clean and sleek solution so the latter is the least attractive at the moment. Really not sure where to go from here - any thoughts? Cheers Link to comment Share on other sites More sharing options...
timsabre Posted December 3, 2015 Share Posted December 3, 2015 How long does it have to run for? Link to comment Share on other sites More sharing options...
Munro Posted December 3, 2015 Author Share Posted December 3, 2015 Potentially up to an hour, on and off? More like 30 mins continuous running I'd expect. Link to comment Share on other sites More sharing options...
alistermorton Posted December 3, 2015 Share Posted December 3, 2015 What sort of power consumption? Is it LED festoon, or incandescent. Do you just want on/off, or do you want dimming control? Link to comment Share on other sites More sharing options...
timsabre Posted December 3, 2015 Share Posted December 3, 2015 I was thinking maybe a big computer UPS might be a solution. An hour's a long time though even if you have LED lamps in the festoon. Link to comment Share on other sites More sharing options...
Munro Posted December 3, 2015 Author Share Posted December 3, 2015 At the moment I'm looking at incandescent, LED *could* be an option. The incandescent would be 80x 15w lamps. I'd have to look into an LED option. The ability to dim would be appreciated. Not sure how I'd make this work DMX wise though, potentially some form of wireless node? Link to comment Share on other sites More sharing options...
Jevans Posted December 3, 2015 Share Posted December 3, 2015 Wireless DMX or dimmers onboard isn't that much of an issue; you can hire wireless DMX, the main issue is power consumption. 80 15W lamps gives you a total consumption of 1.2kW - a 12V lead acid deep cycle battery with a, say, 100Ah rating would in theory power exactly that for an hour, but in reality you'd never be able to pull that much current from a single one of those batteries for an hour, plus the consumption of the control kit, plus inefficiencies in whatever inverter and dimmers you use, plus even deep cycle batteries don't allow full discharge, plus voltage drop during discharge increases current draw... you're looking at having several of these batteries arrayed together. Perfectly possible, but heavy and expensive. Link to comment Share on other sites More sharing options...
Munro Posted December 3, 2015 Author Share Posted December 3, 2015 Sounds like the only option. Does anybody else have any wacky ideas, or ways that they have combatted this issue in the past? Open to all suggestions. Link to comment Share on other sites More sharing options...
themadhippy Posted December 3, 2015 Share Posted December 3, 2015 Does the truck always land in preset positions? if so some sort of floor pick up.? ,otherwise id look at trying to fly the cable in from a central point and have some sort of auto tensioner,bit like a seat belt,to keep the cable tidy Link to comment Share on other sites More sharing options...
gyro_gearloose Posted December 3, 2015 Share Posted December 3, 2015 I'd use LEDs to start with. That way you'll easily get your current consumption below 200W, as opposed to the 1,200W you'll need for incandescents. Your battery requirements will then be much lower, so you could use a small-ish 30-40Ah lead-acid battery. However if these batteries are still too bulky for you (you did say you need to hide them in a flat rather than a truck) you could always use Lithium batteries. Link to comment Share on other sites More sharing options...
adam2 Posted December 3, 2015 Share Posted December 3, 2015 Batteries are viable especially with LED lamps. Consider perhaps 2 watt LED lamps, these should be brighter than 15 watt incandescent. 80 lamps would be about 160 watts. Allowing for inverter losses that is about 16 amps at 12 volts. A single 75 or 80 AH deep cycle battery will supply that for an hour with a generous margin. Alternatively and at rather greater expense, consider a number of 12 volt 7AH sealed lead acid batteries, these are more easily concealed along the base of a flat than is a single large battery. Some such lamps are dimmable, though often not very well at the bottom of the range. Dimmers work from inverters but not always very well. If you can dispense with dimming, then 12 volt lamps could be used. Please take great care with anything involving batteries, correctly rated fuses are vital as close to the battery as possible. Or use mains voltage from an existing dimmer. Cable reels are available that are self retracting, and coil or uncoil the flex as required. They are primarily intended for power tools and inspection lamps in workshops but can of course be used for other purposes. Link to comment Share on other sites More sharing options...
Jivemaster Posted December 3, 2015 Share Posted December 3, 2015 Wireless DMX is possible, Battery power is possible, Festoons of fairy lights is easy Leds use less power usually. You need to fill in the details about light output needed power input available and run time needed. THEN we can offer some kind of guesses as to what kind of battery, how much it will weigh and cost. Also with batteries charge regime is important, how many shows will you need to do between battery charges (two shows on one day may make some design aspects a little difficult just to get the recharge in) Some of the Li rechargeable power packs available may well offer some useful power in a small but expensive package. As ever budget will determine whether the project will work. Link to comment Share on other sites More sharing options...
DrV Posted December 3, 2015 Share Posted December 3, 2015 Battery capacity is clearly going to be your major headache. Multiple small batteries and multiple smaller loads might make it easier to build into flats but would complicate your recharging protcol. However it would add a degree of fault tolerance to the design. The radio and dimming side would be easily handled by City Theatrical D2s or D4s. They have very good LED dimming at the bottom end and are very compact considering that they will handle 10A per unit. Disclosure - I do a bit of work for CTI occasionally, but I'm not on comission! Dave Link to comment Share on other sites More sharing options...
ImagineerTom Posted December 3, 2015 Share Posted December 3, 2015 Since the OP is a student I'd hazard the majority of the suggestions so far are hideously impractical. The cost of batteries, chargers and wireless DMX as well as the necessary inverters to get "mains" powered units working is probably going to be more than the entire budget of the show. To the OP - either you need to be looking at running a mains cable to the unit (you'd be amazed how many shows with moving pieces of scenery manage to do it with cables hanging off the back of them that the audience never notices) or you need to be looking at an entirely low-voltage based system with some off-the-shelf battery packs and wireless remote controls cobbled together to give you the basic level of control. Link to comment Share on other sites More sharing options...
DrV Posted December 3, 2015 Share Posted December 3, 2015 Since the OP is a student I'd hazard the majority of the suggestions so far are hideously impractical.Hadn't noticed that :-) Link to comment Share on other sites More sharing options...
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