Remote Power Generator ?

[TommyT]

Hey Guys. Anyone do some remote recording ? really remote? anyone calculate what the average PT Rig uses in power with some speakers & a few screens? wondering how big a generator you'd need to keep a HD system on a quad & a few screens & speakers running...

Cheers Tom...

[georgia]

any reasonably small generator will work.. the real problem will be the noise generated.. Not the wattage.

Check out: Coleman Sport Generator — 3.5 HP, 1850 Watt, Gasoline, Model# PM0401856

As long as you're using small powered speakers you're good to go.

MAC G5 Quad processor: Line voltage: 100 - 125V AC or 200 - 240V AC (wide-range power supply input voltage) Frequency: 50Hz to 60Hz, single phase Maximum current: At least 10A (low-voltage range) or 5A (high-voltage range) Add to that a couple PCI cards. Most flat screens are less than 10 watts. A pair of 1031 genelecs, my guess, would be around 300 watts with load.

so somewhere around 1200 to 1500 watt generator will work fine. You'll need a blimp for it though or it will make you crazy.

cheers
geo

[Craig F]

don't forget a good power filter between the generator and the equipment. most small generators have some surge and sag

[spiritG]

An alternative to a generator would be a few deep cycle marine batteries with inverters. The only noise would be that the inverters sometimes have fans. For long recordings you would have to change out batteries before they run out- and there is a risk a battery might run out suddenly without warning. Powering a couple of 300 watt power amps tends to last about 3+ hours on a good heavy duty deep cycle battery with about 50% use- so when one knows what the working load would be then one can ballpark what to expect. Not a bad idea to set up the system and test how long it will record a couple of times prior to actual use. Deep Cycle batteries seem to hold a little bit longer charge after they have been charged and depleted a couple of times when done properly.
One could gain time by putting different components on seperate inverter/battery combos- BUT problems (conceivably even hardware damaging) could occur because the 60 cycles on each part of the system would be out of sync and drifting from each other. With a mixer on one inverter battery and the powered speakers on another with a laptop/ firewire drives/MOTU interfaces it worked and another powered speaker on another it seemed to work ok, but even on a generator you can get weird spikes and noises etc. unless things are highly regulated between the power source (generator or battery) and the power load. In other words inverters and power regulaters etc. Cheap inverters seem like they will usually work with a few random noises or glitches possible- they put out modified square wave AC. Theoretically a pure sine wave inverter would be better, but they are more expensive and require more battery power to do the same work, and there are varying grades and qualities of sine wave- regarding frequency accuracy, stability and harmonic distortion in the power wave form. A big expensive generator might have good quality inverters and maybe additional regulation built in. How much this will affect you will depend a lot on the sensitivity of the equipment you use- largely based on how the power supplies are designed- how much tolerance they have for fluctuation and out of range stuff.
A laptop would be an alternative- either on it's own battery or on an inverter (with the laptops internal battery sort of serving as a battery backup). The interfaces might need power, and/or any external harddrives. Conceivably one could use a laptop with a buss powered interface(s) (MOTU traveler or many USB interfaces) and an internal drive (you might need a fast one for more than just a few tracks- moreso with 24 bit than 16 bit) or a buss powered drive. With a lot of buss powered stuff (too much at the same time might not even work) the laptop battery would go quickly- possibly even just a couple of minutes.
Digi's artificial "if you want a lot of tracks buy TDM" policy has kept me using Digital Performer so that live recordings beyond 18 tracks can be done on a laptop- I don't usually notice a lack of qualtiy that wouldn't be attribute to getting feeds from a PA board and SM57's. After recording DP can be better for any needed tempo mapping of fluctuating live performances, then the tempo map can be exported with midi (if there is a tempo map) and the audio files imported into the new protools session for overdubs/mixing. Special note- on a laptop the higher the track count/ and bit rate/ and the longer the continuous recording the more chance a "recording aborted" situation could occur as the laptop is pushed to it's limit. The risk of recording aborts can be lessened by stopping and restarting the recording in as frequent of intervals as program content allows. It is possible though to get 24 tracks of 24 bit audio for 2+ hours on a clean nonfragmented drive or two- but risky. Doing under an hour much safer- and doing 10 or 15 minutes at a time still safer. 24 bit seems to tax system resources almost twice as much as 16 bit. Have the system efficient and stipped down to essentials on a laptop- no plugins etc if possible.

So there are a few ways to do location recording where there is no power grid. Research power issues more, be careful because batteries and generators have potential safety issues to be careful about (so does power grid- but battery/generator issues might be less familiar) and Good luck.

[georgia]

the marine batteries are a reallly good idea. We've did this on an HD shoot a few months back. We only had a laptop with FCP, A DVcam deck, a card reader for the HD camera,and a couple disks.. We used it to transfer video on location from a digital camera to FCP. But it shoudl work well if you don't push the amps to hard...

cheers
geo