I am planning to possibly shoot a portion of my script on a old city bus and lighting for this will need to be clear. Anyone have any recommendations? .... I would want white light.
One alternative is a Battery/Inverter set up that is commonly called a "Battverter." A "Battverter" system consists of a deep cycle 12V DC power source (usually Marine Cells), a 12V DC-to– 120V AC True Sine Wave Power Inverter, and a Battery Charger. Battverters can work great for traveling car shots but offer limited capacity and run time. The largest true sine wave inverter I have seen is 1800W which is just enough to run a few Kinos. Your run time will depend on how many batteries you wire in paralell. Here are some production stills that show you two Battverter systems that a local gaffer that I work with, Guy Holt, built to run kinos to light the inside of an airport shuttle bus for the feature "Shuttle." The first is a 750W "Batt-Verter" rig wired into in Calzone case and mounted on a Exo-skeletal pipe rig that also held Kino Flos.
(Exo-skeletal pipe rig on shuttle to rig lights and mount 750W batt-verter on front (covered for rain protection)
To maximize the running time on however many batteries you use, I would suggest you make up a "jumper cable" to attach to the leads of the bus’ alternator. That way you can use the bus alternator as a generator to run the lights during set up and rehearsals. When it comes time to shoot, shut off the engine and continue to run the lights on the silent Battverter alone. Running the vehicle engine between takes charges the batteries so that they will run longer.
(750W "Batt-Verter" Rig wired into in Calzone case and tied into the Shuttle’s alternator)
The production stills below show you a more elaborate 1800W Battverter system that we built to run 16 - 4’ kinos tubes inside the airport shuttle bus. Use this link - http://www.screenlig...emailintro.html
for details on how we wired it into the shuttle bus.
(1800W "Batt-Verter" Rig wired into the back of Shuttle)
Keep in mind that when voltage goes down, amperage goes up. All wire that carries 12V DC has to be sized accordingly. For instance to supply 12 volts to the 1800W inverter used on the shuttle bus required that we run 2 ought feeder to the buses' alternator. Also be sure that the alternator is large enough to take the load without burning out. On our 1800W rig we were able to run four 4' 4 Bank Kinos.
(SL&G's custom 1800W BattVerter powers 16 - 4' Kino Flo single tubes rigged <br> in the interior and on the exterior of an Airport Shuttle)
If you need more than 1800Watts you should consider towing a small portable generator behind the bus. I would suggest a Honda EU6500is Inverter Generator with a transformer/distro. The Honda is so quiet that you will not notice it over the noise of the bus engine. When the bus is stationary, if you hear the generator at all, it will sound like the bus engine is idling. The Honda EU6500is inverter generator is much quieter than the older movie blimped Honda EX5500. Part of what makes the new Honda EU6500is so quiet is it’s “Eco-Throttle.” The Eco-Throttle’s microprocessor automatically adjusts the generator's engine speed to produce only the power needed for the applied load. It can do this because the Inverter Technology of the Honda EU6500is enables it to run at different RPMs and maintain a constant frequency and voltage. Where conventional generators like the Honda EX5500 and ES6500 have to run full speed at a constant 3600 RPM to produce stable 60 hertz (cycle) electricity, a Honda EU6500is only needs to run as fast as required to meet the load demand. Since their engines do not have to run at full speed, and the fact that an inverter generator generates 20% more power per revolution of the engine, makes the Honda EU series of inverter generators substantially quieter than conventional models.
To make them even quieter, Honda has designed a new separate triple chamber construction and a new centralized intake/exhaust system. The net result is that the EU6500is is half as loud (ten decibels) as the comparable EM7000is and ES6500 generators typically found at lighting rental houses. Honda's EU Series generators operate at 34 to 44 dBA at 50 ft. - well below what is required for trouble free location recording and quieter than your typical Crawford 1400 Amp “Movie Blimped” Generator. With sound specs this good all you need to record sound without picking up generator noise is a real distro system that will allow you to tow the generator behind.
Guy Holt's company here in Boston, ScreenLight & Grip, builds a step-down transformer for 6500W generators that doubles as a distro box. Their transformer/distro steps down the enhanced 240V output of their modified Honda EU6500is to a single 120V/60Amp (7500 Watt) circuit that is capable of powering larger lights, or more smaller lights, than you can without it (see my post at http://reduser.net/f...ead.php?t=33385
for more details.) You might want to look into using their 60A transformer/distro because it will enable you to tow the generator behind, yet have a flexible distro system inside the bus. You would use heavy duty 250V twist-lock extension cable between the transformer/distro on on the bus and the generator on a small trailer. The single heavy-duty 250V twist-lock cable would eliminate multiple cable runs to the generator and give you plug in points conveniently located in the bus.
Their 60A Full Power Transformer/Distro is equipped with the industry standard 60A/120V GPC (Bates) receptacle so you will need additional 60A GPC extension cables, 60-to-60 Splitters, and fused 60A GPC-to-Edison Breakouts (snack boxes) to run power around the bus - breaking out to 20A Edison outlets at convenient points. The best part about their transformer/distro is that no matter where in the distribution system you plug in, the transformer/distro automatically balances the additional load, so that you don't have to run back and forth between the bus and trailer to check the load balance. If you use it with their modified Honda EU6500is generator, you simply plug in lights until the load wattage displayed on the “iMonitor” of the generator control panel reaches 7500 Watts. An overload alarm on the “iMonitor” display will tell you if you inadvertently overload the 60A Transformer/Distro. It is so simple that you don’t need to be an experienced electrician to operate it.
If you don’t want to tie marine cells into the alternator of the bus, I would highly recommend this new Gen-set system. I have used it on several Red shoots. The generator is super quiet. The transformer/distro gives you access to more power (7500 Watts continuous) and greatly simplifies your set electrics. For example, as I mentioned on my Red User post, I used one recently to power a lighting package that consisted of a 2.5kw, 1200, & 800 HMI Pars, a couple of Kino Flo ParaBeam 400s, a couple of ParaBeam 200s, and a Flat Head 80. Given the light sensitivity of the Red Camera, this was all the light we needed to light a large night exterior. Use this link for more information about using transformers on portable gas generators: www.screenlightandgrip.com/html/emailnewsletter_generators.htm
- Eileen Ryan, Boston Gaffer