Determining my needs for a generator?

[Jacques E. Bouchard]

I may have scored space to shoot for free in an old theater (built 1929) that's slowly being renovated into a cultural center. Problem is, they have no electricity, so we'll have to get a generator to run our lights and applicances (small fridge, microwave, etc.).

I'm looking at generators to determine how much this could cost us, but I have no idea what power would be sufficient. We will build a small set in the space (15'X15') and light it like a regular room with a ceiling light, with one powerful light in the window to make it look like daylight streaming in. We'll also need to light the rest of the space for the cast and crew, run a small fridge, microwave, other lights to see where we're going, etc.

What would be a good wattage to insure we have enough power? How much gas would such a generator use to run 8 hours?


J.

[Andrew Dean]

Originally Posted by Jacques E. Bouchard

I may have scored space to shoot for free in an old theater (built 1929) that's slowly being renovated into a cultural center. Problem is, they have no electricity, so we'll have to get a generator to run our lights and applicances (small fridge, microwave, etc.).
J.

The power needs would be dictated by the type of light you are using. I.e. 2,000 watts of tungsten, HMI, Fluorescent or LED are vastly different amounts of light. If you are renting lights then it might pay to rent HMIs vs. a bigger generator especially with the price of gas.

Is the light coming through the window soft or hard? If soft, you could use a big kino wall-o-light for like 500 watts. If hard, a 575w or 1.2k "sungun" hmi fresnel or par would be heaps of sunlight.

Were this my shoot, i'd try to buy a honda 2000i generator and work within the 2000 watts. It would be a little bit tight, but I think well worth it to own the 2000i. The honda i gennies are whisper quiet, easy to drag around, very gas efficient and infinitely useful to video shoots. The 2000i i think is the sweet spot for size/power/noise and is basically the equivalent of a normal household circuit stuck to a briefcase.

If you are stuck with tungsten lights, then you'll probably want at least 2,000 watts for the window light, plus another couple hundred for the top light. 3-400 for the appliances... I reckon 4,000 watt gennie minimum. That or two 2000i so noise isnt as much of an issue.

Just some "fuel" for thought. You'd need to specify your lighting to know what wattage you need.

Were this my shoot I'd also look into paying a neighbor to run an extension cord. You could offer 1/2 the cost of the generator hire + gas for a drop from next door and not have to deal with the hassle, noise and fumes.

Fumes... yeah, even silent gennies make those, so be sure you have a safe and also ventilated place for the gennie.

hope that helps!

[Jacques E. Bouchard]

Thanks for your reply, Andrew. Very helpful advice. I'd very probably go with tungsten for having shot with them before. The cost of rental would be lower, and the space is large enough that heat dissipation is not an issue.

I never thought 2000w would be enough? I might use some of my own lights (to save on rental), 7 X 500w open-faced tungsten lights. That alone would be 3500W (assuming we use them all at once), right?

As for running the extension cords, that is one option (at least for the fridge to keep it running) but if our power consumption is >3500w then we'd need some very heavy-duty cords and all they have is a little office, we don't want to blow their breakers...

The space is on the ground floor right off a commercial street, so we can leave the generator on the sidewalk to vent the exhaust. We're not recording sound, so noise isn't really an issue (except to the neighborhood).

BTW, I found that tool rental places have MUCH cheaper prices on generators than movie equipment places. All the gas generators they rent rate at around 1 gal/hour.


J.

[Battle Vaughan]

Needless to mention, but I will -- watch where the exhaust goes. Every hurricane we have people killed by carbon monoxide because they ran generators where the fumes could be drawn into the house....or worse, they tried to run them IN the house.... good luck! / Battle Vaughan/miamiherald.com video team

[Jacques E. Bouchard]

Originally Posted by Battle Vaughan

Needless to mention, but I will -- watch where the exhaust goes. Every hurricane we have people killed by carbon monoxide because they ran generators where the fumes could be drawn into the house....or worse, they tried to run them IN the house.... good luck! / Battle Vaughan/miamiherald.com video team

Indeed. I'm not even using the generator inside with an exhaust pipe going outside. Too risky.


J.

[Battle Vaughan]

Right on. Incidentally, second Andrew's mention of Honda, we have one for emergencies in our equipment pool, it is the best I've seen -- quiet, reliable and good on gas consumption. We have run studio strobes off it, although I don't recommend that as the voltage surges aren't good for the packs. If you can get something with good voltage stabilization it would be a good idea, particularly for HMI, I think.

After Hurricane Andrew I bought the only generator I could get my hands on, ran the fridge and microwave (not at the same time) and burned them both out with the voltage surges as they cycled on and off.....the industrial generators I've seen movie crews using are, of course, another animal altogether..../bv

[David W. Jones]

You can run 2 of those Honda generators in tandem.

[Andrew Dean]

If you are going to run tungsten, then your power (and therefore gas) needs will be much higher. HMI run approximately 4-5 times more efficient than tungstens. So, 2,000 watts of hmi would produce roughly the same light as 9-10,000 watts of tungsten. So, yes, 2,000 watts would be anemic for tungstens, but would easily overpower a room with hmi (or fluoro).

I dont know how much your local shop rents HMI for, but with the cost of gas it might be a wash.

The honda "i" series runs through a fancy line conditioner then a DC phase then an inverter, so the power produced by it is a true sine wave and is just as safe for delicate and critical electronics as a wall outlet. (safer, depending on where you live. hehe) Here in NZ you see the honda inverter generators on most film sets... although sometimes just powering the coffee maker (quietly).

Whatever gennie you get, be sure to chain it up if you are running it outside. Crooks LOVE generators. On the one hand you'll know instantly when its been stolen, but on the other, you'll have to feel your way to the exit to chase them. hehe.

so 7x 500w open face (hopefully not all in the 15x15 room), plus what, 1,000w for the microwave (i assume a 1,000w microwave draws 1,000 watts?) and 500w? for the fridge.

Thats 5,000 watts or 41+ amps at 120v. If you want that all in one power cord, you're going to have to get a monster 60a cord and a distribution box at the set. I'm assuming if you were versed in rigging up distro boxes (i'm not) then you wouldnt be asking. For simplicity and safety you'd probably want to run multiple leads with no more than 15a on a single domestic extension cord, so 3 of those 500w per extension cord back to the gennie. You'll probably want a generator rated higher than you need to cover spikes when flicking stuff on and the fridge cycling. So, 6,000w generator?

So, yes, 3500w is too much to pull off a single extension lead from the neighbor, but its too much to pull off a single 15a extension lead from the gennie too.

I normally wouldn't speak up on this subject, since I'm FAR from an expert, but I chimed in before because nobody else had, yet. I'm just brainstorming through what i'd be considering were it my shoot. I hate dragging around giant generators and running gobs of extension cords. I also hate blowing circuits and having to hunt around locations trying to figure out where the various circuits are run. (clearly, i'm not cut out to be a gaffer) So, earlier this year I said "screw it" and bought all HMI, fluoro and LED fixtures. Now I can run the "equivalent" of like 8,900w of tungsten (if you count a fluoro diva as the same as a 2k in a chimera) off a single outlet.

So thats my thoughts and disclaimer. Hopefully its useful. Note that the "right" way to do it is a bigass generator with a huge 240v 60a or whatever drop over to the set where you have a distribution box that splits it out to multiple 120v circuits. Also note that the "right" way to do it usually requires an electrician or gaffer and is always more expensive than you'd think. hehe.

Cheers!

[Dany Badaoui]

there are generators with a feature called sinewave, kinda works like inverter air conditioning to prevent surges. probably better off renting an industrial one if you wont need it too long.

[Jacques E. Bouchard]

Thanks again for your invaluable input, Andrew.

Ideally I'd have the budget to hire an electrician and gaffer and send them out to rent whatever equipment we'll need. But in reality my budget will probably be limited (I'll know for sure in a couple of weeks) and I'm preparing to cut expenses.

My 7 X 500w lights are free, and I can probably borrow a 5kw generator from a contractor. Alternately, I can rent a 10kw generator that's much quieter for $450/week but I don't know if the output is conditioned. In either case, I was advised to lock the generator in our van and run an exhaust pipe out the window to control both noise and theft/vandalizing. I'm hoping to run the fridge and microwave on an extension from the building so as to keep them running 24 hours.

My local equipment rental place has HMI lights starting at $200/day for 200w, so all the lights for a 5-day shoot would cost a heck of a lot more than running free tungsten on a gas generator...

Heat is not an issue. This place is an old theater built in 1929 that was partially destroyed by fire almost 20 years ago. They gutted the inside to renovate, and it's like one big cool concrete cavern. It's also verrrry creepy in there, without any lights... ;-)

Only the walls of the set are 15X15. There'll never be more than 2 or 3 walls in place, and there is no "ceiling". Ventilation is great.

I'm supposed to meet with the building's electrician next week. I know they have SOME lights in there for the workers who started renovations, so who knows there may be enough for us to run everything and just pay for the electricity. Also, I may very well get all the money I asked for and rent the best toys... I mean, equipment (I can imagine half of you sighing wistfully) :-)

In either case I'll report back here and keep everyone posted.


J.

[Andrew Dean]

awesome. sounds like you have it all sorted. Hope the shoot goes well!

$200/day for a 200w? Gadzooks. Makes the cool lights 150w cdm for $450 a lot more sexy. hehe.

cheers!

[Jacques E. Bouchard]

Originally Posted by Andrew Dean

awesome. sounds like you have it all sorted. Hope the shoot goes well!

You know how it is: I'll have absolutely everything planned down to the last detail, and on the first day I'll realize I forgot something crucial. ;-)

$200/day for a 200w? Gadzooks. Makes the cool lights 150w cdm for $450 a lot more sexy. hehe.

If I had to pay $5,000 to rent lights over a 5-day shoot, I'd buy them instead. At least I'd own them.


J.

[Kirk Candlish]

There is a new Honda model coming this summer that you might want to consider: Honda Power Equipment - EU3000i Handi

I have the 2K EU2000iA and it's outstanding.

[Shaun Roemich]

Originally Posted by Andrew Dean

$200/day for a 200w? Gadzooks.

Keep in mind that HMI lights are TYPICALLY 4 - 5 times brighter at any given wattage range (a 200 watt HMI is probably close to 1000 watts of tungsten) and THEN if you need full daylight (5600k) you''d need to gel the tungstens losing two stops.

So, IF daylight is your need, HMIs are 16 - 20 TIMES more powerful than tungsten instruments converted to daylight.

And HMI instruments typically have significantly more "throw" than fluorescent or LED sources, at least for the time being.

And yes, I'd make sure that you had some kind of voltage regulation if using a "consumer/commercial" genny instead of an industrial film style as surges will not only affect colour intensity and temperature BUT will also jeopardize the lamps in tungsten fixtures. And relamping 5 instruments a couple of times due to blown filaments will eat into your budget "savings" REALLY quickly.

[Shaun Roemich]

Originally Posted by Jacques E. Bouchard

with one powerful light in the window to make it look like daylight streaming in.

Jacques: I'm sure I overstate the obvious but if you're looking for that classic "light streaming in through a window" volumetric light look (ie. you can SEE the rays of light in space), make sure to rent a hazer (NOT a fog machine) so that the light from your source has microscopic particles to illuminate.