Portable power for monolights

Discussion in 'Digital Photography' started by seenew, Nov 12, 2008.

  1. seenew macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #1
    Hey guys, I just bought some monolights from Alienbees and wanted to get their portable battery pack, but it was on backorder. I'm kind of in a crunch for time and am wondering if there are any like.. general purpose battery packs that are powerful enough to run three monolights off of for more than a few shots. I believe these lights are 640ws if that means anything to you.

    I found this power inverter at Home Depot that turns a car's 12volt DC current into 110/120volt AC current (which the monolights run on) with 2500 watts at up to 20.8 amps. As far as I can tell, these monolights run at an average of 6 amps, peaking at up to 18 amps during recycling. Would this inverter be able to power three of these lights at once?

    I know pretty much nothing when it comes to measurements of electricity, so any help is appreciated.

    Oh, and that inverter is like $265. :( I realize I will be dropping some serious dough (well, relative to a student budget) for this, but I want to make sure I am buying the right thing. My alternative is to buy like 300 feet of heavy duty extension cords. Haha. (Which I am seriously considering)
     
  2. FrankieTDouglas macrumors 65816

    Joined:
    Mar 10, 2005
    #2
    How much are generators?

    I borrow a really big generator and use a Vegabond on some shoots. But if you can find a generator for cheap, go with that.
     
  3. seenew thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #3
    I'm headed to Home Depot now... I wish AB had the Vegabond, but like I said, they're on backorder. :(

    How much are generators anyway?
     
  4. ChrisA macrumors G4

    Joined:
    Jan 5, 2006
    Location:
    Redondo Beach, California
    #4
    Buy the extension cord. But look carfully at the wire gauge. Yo want at least #12 wire and #10 is best. These kinds of extension cords are sold for use at construction sites. They will have three prong "twist lock" connectors and you buy adaptors for "houshold" outlets. You will need a shippinf/storage case for the extension cord, a case with wheels is best. Home Depot sells a nice case made by stanly that cam hold you whole system for about $70. This stuff will weight in at about 100 pounds and then you add the batteries

    About the inverter. Yes it will work. BUT,.... If 6 amps of AC are required the inverters will need to pull about 60 amps out of the battery bank. and the demand could go as high as 180 amps. You are looking at some serious batteries. You'd need some marine batteries wired in parallel and if you are smart a battery box and 200 amp fuse. Wires that can take 200 amps have conductors inside the same diameter as your thumb. Wire like that runs about $6 per foot and you'd need both a positive and negative. I've wired inverters into boats, It's not cheap. And then you'd need a battery charger too. batteries need to be rated about 4X more amp hours then you need. So if you plan to draw 60 amps for one hour, buy a battery bank rated for 240 amp hours at 12 volts. You can go lower but the lifetime of the bank will be shorter by a lot. For example you could buy a 60 amp hour bank and dischange it down to "zero" but the batteries would be "toast" after only 2 or 4 cycles. Going with a system 4X larger you might get 250 to 500 charge/discharge cycles.

    $265 is a good price for an inverter. Make sure it is rated at 18 amps. But expect to spend another $200 on the wire and fuse and connectors and tools. Make absolutely certain there is a fuse within 18 inchs of wire length of the battery. A battey this powerfull can vaporiz a wrench if you drop it across the terminals. No kidding. Place the fuse inside the plastic box, have a 200 amp shut off switch ans use the right kind of conectors rated at 200 amps. Good sourse of supply are marine hardware stores.

    Building a barrty, charger, inverter system that can suply up to 18amps and 6 amps for hours at a time required some basic enginerring. I'd seriously suggest buying the parts from a retailer who can make helpfull suggestions and offer some real consulting. Home Depote is NOT such a retailer. The guys who work there just don't know enough. A better place might be "West Marine" but even they are un-even and you may have to ask around to get the right help.

    Even if you buy a generator also buy the long extension cord. Keep that noise 300 feet away.
     
  5. seenew thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #5
    Hmm, well I didn't get to read your post, Chris, before I went. I ended up getting this
    http://blackanddecker.com/ProductGuide/Product-Details.aspx?ProductID=16896
    [​IMG]

    It was only $99.
    As far as the guy at Home Depot Could tell, it should power at least one, if not both of my regular strobes, and I might pick up a second one for the ringflash.
    I'm not exactly sure if it will work, though. I just got home from a long day at the printmaking building (finals week) so I'm just now getting to charge it up.

    Please, feedback is appreciated (but try not to make me feel too stupid if I made a mistake!)

    (PS: They had a small generator there for $399, but I decided to try this first, because it was cheaper and much smaller/lighter/quieter)
     
  6. ChrisA macrumors G4

    Joined:
    Jan 5, 2006
    Location:
    Redondo Beach, California
    #6
    It might work. The unit is rated at 400W at 120V that means 400/120 = 3.3 amps but the B1600 recycles in 2 seconds so it's only a 2X overload. Likely it will not overheat in two seconds.

    During re-cycle I'd expect the draw on the internal battery to be about 60 amps. the 19AH battery can supply maybe 15/60 hours or 15 minutes of power that's 900 seconds or 450 recycles. Not to bad

    The model lamps are 150W or just over 1 amp each. you might set an hour of use. if you never recycled the flash. So maybe 200 "pops" and 1/2 hour of using the model light.

    But the above assumes you run the battery down to zero. Do that and it will have a short life. run it to 50% and you may get 50 or so charge/recharge cycles from the inaternal battery.

    Sorry about my last post. When you said 6 amps I assumed it was a continuos load with peaks up to 18. That really would be very very different. I looked up the specs on your lights.

    My Norman studio power pack draws a full 18 amps during re-cycles and there are four 100 watt model lamps. I bought the system when I shot medium format. I used to shoot film at ISO 160 or less at about f/16. That took a lot of light. But now with digital SLRs I use so much less light.
     
  7. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

    Joined:
    Jan 11, 2007
    #7
    USE CAUTION!

    I don't know what type of power supply those lights use - but an inverter that cheap is the Modified Sine Wave type - which is NOT the same as standard out-of-the-wall electricity. (which is pure sine wave)

    This can have some serious implications depending on what type of power supply the device uses. For example - a MSW inverter will have trouble running an electric motor and some power supplies. Even if it has "enough" power - the devices rely on a true sine wave to run.

    If you do use this inverter - I'd double check the lamps, and make sure they're not running loudly ,or generating excessive heat - if they are, I'd stop and search out a true sine wave inverter or other power source.

    Also consider lights that run off of 12VDC - I'm sure they exist for your application.
     
  8. seenew thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #8
    So then this should probably work? Should I buy one for each light? I have two B1600's and the ringflash is an 800. At $99 a pop, it's about equal to the cost of the Vegabond II, which I would prefer, but this unit seems to be pretty handy so far and I literally can't wait for a restock of the Vegabond system..
    The major thing is that I need to shoot this weekend, and the manual says to charge these packs 24 hours the first time, so if I need to buy more (one or two) then I need to buy them soon and set them charging so I'll have enough time.

    If you wouldn't mind, could you break down the numbers just a little bit simpler for me? (like metaphors or something.. I've heard water works well for describing how electricity works-- I'd just like a clear picture of what I'm working with here)
    I really appreciate the responses, Chris, really.
     
  9. seenew thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #9
    are you referring to the original inverter I posted, or this Black & Decker I just bought?
     
  10. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

    Joined:
    Jan 11, 2007
    #10
    Both of them. Pure sine wave inverters run a lot more money. Talking 2000 bones for a 2000w inverter.

    I'm not trying to scare you away - but I don't want you to damage your equipment if it doesn't play well with a modified sine wave inverter. I don't know enough about your lights to say for sure, just keep an eye (and ear) out when you first start using them.
     
  11. MacNoobie macrumors 6502a

    MacNoobie

    Joined:
    Mar 15, 2005
    Location:
    Colorado
    #11
    Couple of options honestly, first what about a computer battery backup? buy the highest one you can since those are usually Pure Sine Wave I believe (correct me if I'm wrong someone?) something like an APC (American Power Conversion) will do the trick pretty well even if you get like 100 pops out of the battery its still not bad.

    Finding a cheap generator gonna be hard since I know Honda makes some but its still 700+.

    Qflash? yeah I know you spend the money on the strobes but if you need on location studio quality flash and you do a lot of on location stuff why not get a QFlash T5D-R + Turbo Battery?
     
  12. seenew thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #12
    Well crap. I just read a few places that AlienBees strobes have bad luck with modified sine wave inverters, which is what that Black & Decker unit is.
    UGH.

    What now?!
     
  13. termina3 macrumors 65816

    Joined:
    Jul 16, 2007
    Location:
    TX
    #13
    I don't think they're a pure sine wave. Over the hurricane I looked into acquiring one that was, an off-brand model, and it was ~$6000 for 3500watts.

    Granted, that's a lot of wattage…*but also a lot of money
     
  14. seenew thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #14
    I'm just gonna get 300-400 feet of 10 or 12 gauge extension cords and pick up a couple of Vegabond II's in the next month or so when they're back in stock.

    Thanks for all the suggestions, everyone. Hopefully this thread will be useful for anyone running into similar problems.

    Point is:

    USE ONLY PURE SINE WAVE ELECTRICITY WITH YOUR STROBES
     
  15. compuwar macrumors 601

    compuwar

    Joined:
    Oct 5, 2006
    Location:
    Northern/Central VA
    #15
    Not only that- the unit should be designed with a ground fault interrupt (GFI) so that it won't fry you. The Vagabond II's are designed well, so they don't need an additional grounding rod to be safe.

    It's too bad you're in Georgia, I don't need my Vagabond II until a product shoot on Thursday. The other thing to know about being on battery is you really shouldn't use your modeling lights, as they'll drain the juice right out of the pack.
     
  16. compuwar macrumors 601

    compuwar

    Joined:
    Oct 5, 2006
    Location:
    Northern/Central VA
    #16
    APCs used to all be modified sine wave output, I'm not sure now, but I wouldn't assume pure sine wave unless something actually says it on the box, the quick check of a few APC products on their site produces
     
  17. MacNoobie macrumors 6502a

    MacNoobie

    Joined:
    Mar 15, 2005
    Location:
    Colorado
    #17
    Still though if its safe enough to run a computer I would assume you could do studio strobes off of it.

    I've tried a set of 1250 photogenics off my lil 1400 APC and it worked fine granted I haven't shot a full day or anything but it does work if u can get past it occasionally beeping for being on battery power.

     
  18. FrankieTDouglas macrumors 65816

    Joined:
    Mar 10, 2005
    #18
    Keep your extension cords once you get the Vegabond. You can plug a surge protector into one and power lots of lights at once.
     
  19. compuwar macrumors 601

    compuwar

    Joined:
    Oct 5, 2006
    Location:
    Northern/Central VA
    #19
    Bad assumption, the load characteristics for a computer power supply and a set of strobes are completely different. PCB's strobes require a full sine wave inverter.

    Here's what I found online:

    I also think I've read that the modified sine wave inverters tend to go more towards a square wave under high load.
     
  20. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

    Joined:
    Jan 11, 2007
    #20
    Building a 12vdc strobe is easy - I can't imagine that there would be NONE on the market - especially considering the advantages for portability / remote shooting.

    Give me the lumen requirement / flash duration and frequency, and I could build you one in 24 hours. :D

    I could hook you up with a laser flash lamp - that is strong enough to cause permanent blindness instantaneously. It even runs off of DC! Just, don't get within 2 feet while it's operating - or else you can be killed from the arc. Also, be sure to shield the hell out of any nearby electronics. I'm not sure about portability of the unit - considering the capacitor bank alone weighs over 150 pounds. You also need a water cooling source.
     
  21. MacNoobie macrumors 6502a

    MacNoobie

    Joined:
    Mar 15, 2005
    Location:
    Colorado
    #21
    Well yeah computers almost always have a constant load they really dont spike from high to low that quickly as strobes need to charge quickly. What I dont understand is that if strobes require such a "clean" sine wave then why are the vegabond II battery systems so cheap? or is that just it the inverters are designed only to give pure sine wave patterns for strobes? The other question is arent the strobes sensitive to brownouts or lower then ideal voltages such as an outlet not delivering a constant 120v something more like 118 or 115?


    In all fairness its all power to me and I dont pretend to be an expert on any form of sine wave's and frequency of power sources, yeah I understand the concepts of 60hz and waves existing in power but as to the shape it makes no difference.

    As long as it can power the strobes (like that APC I mentioned) then its fine for what I need honestly. Yeah strobes are probably sensitive to what kinda wave you feed them and they require clean power sources but I've seen people run strobes off little Honda 2000 generators (in some cases daisy chained together) videos on strobist come to mind.


     
  22. MacNoobie macrumors 6502a

    MacNoobie

    Joined:
    Mar 15, 2005
    Location:
    Colorado
    #22
    Well I'm sure you could take a set of lead acid 12v batteries put two in tandem, hook up an inverter to it and build one.

    This kid http://gazoogleheimer.deviantart.com is actually pretty good at that sorta thing we talked over building 12v systems to power strobes before.

     
  23. seenew thread starter macrumors 68000

    seenew

    Joined:
    Dec 1, 2005
    Location:
    Brooklyn
    #23
    generators put out pure sine-wave power. (well, most, IIRC)
     
  24. compuwar macrumors 601

    compuwar

    Joined:
    Oct 5, 2006
    Location:
    Northern/Central VA
    #24
    They're cheap because they use cheap inverters from China. The original VII's were reportedly very bad because the inverter manufacturer hadn't actually ever manufactured inverters before. Their second try at a supplier was a manufacturer who'd done inverters, but not pure sine wave ones. I've used my VII and it seems fine, but there was a high failure rate on the initial ones.

    They can be, as the line voltage is what goes through the quadrupling circuits to fill up the capacitor.

    Just because you've seen a particular set of strobes run off a modified sine wave inverter (and the low-end generators tend to be that too these days) doesn't mean the ABs can be run that way. Not all strobes are designed the same way- however most inverter manufacturers caution against using their modified sine wave products with studio strobes. Once again, all the older APC and a good number of the newer APC UPSes do NOT provide a pure sine wave and are therefore not what you want to use with strobes unless the strobe manufacturer specifically says their equipment is ok with modified sine waves- otherwise you'll need to buy new strobes. Plus someone may be hurt if they catch fire.
     
  25. compuwar macrumors 601

    compuwar

    Joined:
    Oct 5, 2006
    Location:
    Northern/Central VA
    #25
    When I went looking a year and a half or so ago, I found lots of new ones that didn't. I think it's got to do with using inverter components to prevent voltage surges. Those without good voltage regulation are similarly a bad idea.
     

Share This Page