How big a generator do I need?

S

Shacke

Active member
I am looking at filming somewhere with no power and need power for a 650W and 300W Arri fresnel. I was wondering how big a generator I will need.

I saw one advertised for very cheap which has the following specifications and wondered if it would do?

850W generator
Produces 240V output
Three pin output socket
Maximum 3.5 Amps
5/8 hours running time

Thanks for any replies.
 
You've got 950 watts worth of light; no way will an 850w generator suffice. And remember, the rated capacity of a generator is usually quite optimistic; to run 1000 watts of light you'll probably want something more like a 1600w to 2000w generator.

Are you in Europe/240V territory? If not, you'll want to make sure that whatever generator you're using is outputting 110/115v current too.
 
Another consideration is sound. I have had pretty good results from the newer Honda "Inverter" generators. Most rental house in Canada and the USA have them,don't know about Europe.
Check with a local construction tool rental company. And Barry is right on the money, if you need 1k get a 3k genny the difference in rental cost won't be much. dn't foget plenty of extension to locate the thing far fromyou location, Unless that is you are shooting MOS.
 
I'm curious. If I have flouro's is the wattage requirement less?

Like If I have 2 165 watt flouros is a 350 watt generator enough to power them? And for how long?
 
Hi:

Yes, fluorescent lights have a considerably lower current draw than equivalent output tungsten instruments. I have never heard of a 350 watt generator, that would be very tiny with a Hamster on a wheel powering it ;-)

The Honda EU series generators are the best option by far, extremely fuel efficient, quiet and they have crystal sync, which means that your ballasted lights like fluoros and HMIs won't flicker, with a non-crystal sync generator, you will get flicker as well.

Best,

Dan
 
i think honda EU10i or the honda EU20i is a good option. They are light, silent and have enough power to supply your equipment. They can also be parallel connected for more power.
 
Hi:

T-Unit. I constructed a parallel 30 amp box for my two Honda EU2000i. I now have 4,000 watts coming out of a 30 amp connection. Nice to powering my fifth wheel trailer when I camp and nice for powering video lights when I shoot in the boonies.

Best,

Dan
 
Since you will probably want to keep the generator away from the action make sure you get some good power cable. Don't just connect some 16 gauge cords together because they were cheap at the store. If you are looking at more than 50 or 100 feet make sure you have at least 12 gauge extension cords. Personally I'd prefer one of those 10 gauge super heavy duty cords if I was planning on using a splitter to power several lights at 100 feet. The thinner the cord and the longer the distance the bigger chance of having voltage drop.

They are a bit expensive at Home Depot (Costo sometimes has them for a good price) but if you lights start flickering in the middle of the shoot it’s not worth 80 bucks. Also I’d get a cheap voltage meter so that I could make sure you still have a good 110/120 volts coming though the cord. Nothing worse not having full light from a far away generator and not knowing if it’s the generator, the cord, the splitter, the light or the bulb.
 
What are some good ways to deaden the sound of a generator. Obviously, setting it farther away helps, but is there any sort of material one could cover the generator with to quite the sound?\

Mike
 
The best way is to get a quiet generator to start with.

Putting it a long way away, behind a building, helps as well.

I was on one shoot where they covered it with a plywood enclosure. They cut some holes for air intake and exhaust, but it didn't accomplish much; the holes let the sound out, and when they pulled the cover off they found the generator was smoking because it was too hot.

Dig a deep hole and put the generator in it, that can help; the earth will absorb a lot of the sound waves. But you still have to let it breathe.
 
The Honda EUs are the quietest generator available (short of a professional baffled one on a trailer). Depending on your shoot, a towable (real) generator is not that expensive to rent although you do have to have a vehicle capable of towing it or hire the owner who will usually have a large truck to tow it.

Dan
 
A number of strategically placed furni pads on c-stands can be a real help in reducing the noise levels.

I should point out that there is another potential issue when using inexpensive gennys (this reared its ugly head for me when shooting our horrofest entry). The problem besides the optimistic power capability and high noise is the poor frequency control that these types of gennys often have.

If you are only shooting with hot lights, this wont be an issue, but if you have HMIs (magnetic ballast types) or line frequency fluorescents, you need to be very aware of flicker issues. On our first night of shooting our horrofest entry, we used a genny for all our lighting needs (just under 6 kW total) as our location couldn't safely provide the power that we required. Unfortunately we acquired a construction site genny that didn't have a good governor. I was aware that the frequency wouldn't be spot on, so I set the camera's shutter to match the genny (using a production monitor closer to the location) but where we were shooting from we didn't have any power so I had to rely on the camera's EVF and LCD instead of the production monitors we had. By the time that I got the shots off, the genny's frequency had changed enough that I now had a flicker that I didn't see in the camera's EVF (due to the persistence of the display) and I ended up with a bit of flicker.

Just something to watch out for when using gennys not intended for filming applications.
 
How are the rest of Honda's gennies? Do only the EU series regulate the power to allow your HMI's flicker free operation? Or do all Honda gennies operate this way?
 
I doubt that any of the smaller Honda's have a sophisticated frequency regulator. If your budget allows and you are going to use HMIs with these smaller genny's, then go with flicker free (HF) ballasts.

If not, be very aware of the potential for a problem and be sure to reset your shutter often!
 
How would this work? Make a simple folding frame, and attach a heavy pad or carpet to the outside. When it is opened and standing on end, it will form a V. If you set your generator inside that V, all the noise would be deflected away from the action, and it would still be able to breath. Just be sure to keep a bit of room between the equipment and the padded walls.

On the other end of the power cord, attach a small battery back up unit to plug your lights into. It should clean up the power and insure a steady voltage.
 
A ".. small battery back up" will, unfortunately, do nothing to help with flicker problems based upon frequency deviations. These types of devices are non continuous devices and have no effect (other than a bit of unsophisticated filtration and surge protection) when down stream devices are operating as the mains is routed directly through. Further, the capabilities of these devices, in terms of capacity, preclude their use with nearly any theatrical lighting of any size.
 
we stick 'em in the back of a cube van and leave the door open a couple inches for fumes. Just make sure you open the door and leve it open for a while before you jump back in. If you don't have a cube...distance and a good audio personis about all you can hope for.
 
Hi Barry:

The EU series Hondas do have crystal sync (is that what it would be called?) or frequency stabilized output. I have shot many times with both HMIs and fluorescents with my EUs with no flicker, including film and slow motion.

A popular rental house Wooden Nickel also rents the EUs with their HMI and Kino packages.

I suspect that none of the other Hondas, at least on the low end of things are voltage stabilized, flicker/free.

Dan
 
Cool. I called William F Whites here in Toronto. They told me they've had a few issues with square wave ballasts and their EU3000is genny but that magnetic ballasts seem to be fine. How are construction/home depot type gennies and Kino Flo's with flicker? I'm starting a show on super16 in a couple of weeks. I might play it safe and use only 4ft 4banks. The HMI's I have access to are older Strand types - not sure if they're magnetic or electronic square wave. I'll try to get a picture up on Monday and if anyone knows that'll be appreciated.
 
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