generator for powering strobes

JohnRog

I bought a powerhorse 4000 Watt generator (northern tool house brand) this year when it looked like we might see some hurricane action (thankfully we didn't), and as I've been considering picking up some monolights I came across some discussion about the need for a pure sine wave inverter if you're going the DIY route for a battery pack. I assume that the inverter in your generator would be an equally important consideration. I couldn't find anything about the output of my generator aside from the fact that it's listed as having less than .05% THD... they çlam it is clean enough for sensitive electronics... how likely is it that it has a pure sine wave output, and is there a way to test it? (it does have a volt meter built in if that helps at all)

Thanks in advance :-)

ziggy53

The cheap-n-easy method of testing any power source for "line quality" is to plug in an old AC powered AM table radio. That may be hard to find, but it's very sensitive to line noise. Just plug the radio in and detune the radio. (Turn the tuner to someplace between stations.)

If you can find someone with a suitable oscilloscope, that's another good method. How do you know what type of oscilloscope is suitable (I know you're wondering)? The fact is, the person with the oscilloscope should know. If they don't know, find someone that does know for sure.

Digitally controlled electronic flash is very sensitive to both line noise and line frequency, not to mention line voltage. If you try to power on too much at one time, the resulting voltage dip can cause some electronic flash units to act up. That also applies to multiple strobes if they all try to surge at the same time.

If you do the line noise tests and if you can check the line frequency for stability and rate, just plugging in your flashes may be the best way to know for sure whether it will all work in the field.

Understand that plugging in your equipment to power sources other than the power source recommended by the manufacturer is risky and will certainly void your warranty. Unless you assume all the risk, and understand the possible consequential damages that can result, "don't try it".

ziggy53

Seymore wrote: »

Ziggy... would a UPS or line conditioner also serve the purpose of cleaning up the line noise?

A UPS can help, but you need a very large UPS to handle the surge from the flash and you waste a fair amount of power. For running a computer, especially a laptop, it can make some sense coming from a generator through a UPS.

I am not familiar with any reasonably priced line conditioner that could meet the criteria for a flash application.

---

The best bet for powering an AC/mains flash system is to use a proven portable power supply, like the Vagabond system, and couple that to an approved flash, like one of the Alien Bees that are proven to work. There's no guessing that way.

The Adorama Flashpoint II "M" series are another good system that can be battery powered, and there is a Flashpoint 400WS battery powered "pack" light that a few folks like.

Alternately, and with higher risk, there are the Tronix Explorer XT SE units that a number of people have tested. (Do a Google.) But it's not cheap. I can't recommend this route because it too will void your warranty.

Anything beyond this, including the DIY Vagabond-ish tutorials, and you're completely on your own. Lots of risk to yourself and to your equipment. Grounding issues, shorting issues, etc., are just more risk than I can honestly recommend.

I'm afraid that if you want true portable powered flash it's going to be costly, pretty much however you attempt it, if you wish to also be safe.

ziggy53

Seymore wrote: »

Good points and thanks for the answer...

So, any thought on the average wattage (range) pulled for a studio type flash system?

Each studio system, either monolight or pack light, has unique characteristics and has to be explored individually. There are even substantial differences between flashes from the same manufacturer.

I cannot encourage, not even privately, the development of any DIY remote flash power systems because of the safety concerns, both to the individuals building the systems and those using the systems, and to the equipment that would be connected.

The grounding and shorting concerns are primary safety concerns and this stuff has the potential for causing great personal harm.

I'm afraid that the only somewhat reasonably priced truly portable studio type flash solutions are the Vanguard/Alien Bees and Flashpoint "M" series systems. While neither of these systems is "perfectly" safe, each has at least some safety engineered into them as well as proper research into function.

Dan7312

Keep in mind that a lot of UPS systems just pass though the input and only switch over their internal inverter when the lights go out. What they call conditioning just means that they switch over to battery power on over/under voltage conditions.

Seymore wrote: »

Ziggy... would a UPS or line conditioner also serve the purpose of cleaning up the line noise?

JohnRog

Thanks for all of the input guys... I don't have any monolights yet... I was just wondering if I'd be able to use my generator once I do... it's a shame to have that much portable power on hand and not be able to trust it... Oh well... I'm thinking seriously about the flashpoint II lights for when I do. as far as the diy Battery packs go, they really don't seem to make that much sense... It looks like a decent pure sine wave inverter would run upwards of $150 by itself and then you have to cobble a battery and carrying system together after that and you still don't have any guarantees it will work properly or any kind of warranty if something goes awry...

thanks again :-)

ian408

Here's what Paul C. Buff says about generators for it's products:

Q: Can I use a generator with my lights?
A: If you wish to use a generator to power your flash units, we recommend a generator with 1000W of generator power for each flash unit used. This high power requirement is necessary due to the flash unit recycle process. When a flash unit recycles, it creates a brief but heavy current draw for which generators try to compensate. The generators are unable to adjust back to normal output as quickly as the flash unit can recycle, and at this point, the generator output voltage may exceed 140VAC. This can cause internal damage to the flash and/or generator. The use of larger capacity generators minimizes this problem.

According to Buff, you'd have enough power with the 4000W model to run 4 lights.

The best type of generator to use for this application would be an inverter type. These models provide the cleanest power by first converting power to DC and then back to AC to provide conditioned power. A generator like the Honda EUxxxi series would be suitable for the task.

Hope that helps.