12V DC input dimming

[phloot]

I have a show coming up where in several instances I will need lighting to be run from a 12V leisure battery, and controlled by wireless DMX. For the sake of efficiency, I'd like to keep everything on these systems at 12V, negating the need for inverters.

 

Are there any dimmers (or even switchpacks) that run off a 12V DC supply, that will allow me to control via DMX some units? If not, is there a reason this would not be possible with some experimenting?

 

I would also like to smooth the supply coming from the battery, to regulate the voltage - what's the best way of achieving this?

 

Thanks in advance for any help you can offer!

[Shez]

What are the lighting units that you need to control? If they're LED, there are plenty of options out there. 12v tungsten is a little more specialist.

[alistermorton]

Yes, there are exactly the sort of thing you need available from Theatre Wireless and City Theatrical, and no doubt many others. I regularly use RC4 equipment to dim LED and 12V halogen wirelessly, it works extremely well, and can be hired relatively cheaply. You could do worse than contact Lamp and Pencil who handle Theatre Wireless's RC4 range in the UK for a hire quote. You can roll your own solution with wireless DMX and 12V dimmers from eBay, but if it's for a one off the hire cost probably won't be that much more than putting your own solution together, and the off the shelf solution will almost certainly work better. I was shocked at how much better the RC4 dimmer worked compared to a cheapo from eBay - the cheap dimmer was very steppy, the RC4 was completely smooth.

 

I have no connection to RC4/TheaterWirelss/Lamp and Pencil other than as a satisfied user.

 

The RC4 dmx2dim can happily handle a 12V 50W MR16 on one channel or a pair of smaller ones, and they have larger capacity dimmers available too.

 

EDIT punctuation also to add:

 

We use our gear in a theatre with wifi repeaters and mobiles a plenty and (so far - half a dozen or so runs) haven't suffered interference. However, you can get equipment which doesn't use the 2.4GHz bands if you're worried about interference, although it may not be licensable in the UK..

[adam2]

I doubt that you will need to smooth the supply from a battery, it is inherently already very smooth. It is also unlikely that any regulation of the voltage will be needed. A nominal 12 volt battery will supply a very steady voltage at close to 12 volts for almost the entire discharge.

 

The mains voltage varies a lot more, in percentage terms.

 

Do be generous in terms of the battery capacity, the stated capacity is often rather optimistic and only achieved under ideal conditions. There is virtually no electric shock danger at 12 volts, but the fire risk is at least as great as the mains if proper care is not taken WRT correct fuse sizes and locations.

 

 

 

[DrV]

City Theatrical D2 and D4 will do this quite happily. 5A per channel and 10 amp total per unit. There are also some larger units whose model number escapes me at the mo but you should find them on the website. FWIW the dimming curve at the bottom end is extremely good.

[sleah]

Do be generous in terms of the battery capacity, the stated capacity is often rather optimistic and only achieved under ideal conditions.

 

As a rough guide, I would say if your draw is going to be say 100W, then get batteries that can deliver 200W. That's before considering run times. It may sound odd, but you don't want a flat battery at the end of the show. You can't have too much battery reserve! (Well, you could get silly of course ;) )

[phloot]

Thanks all - the City Theatrical units look like just the thing for this. Units will be predominantly LED (mostly floods just for coverage, I have a massive area to cover), and LED tape with controllers again directly from the battery. I think for the scale I'm working on, the tungsten draw will be too great for anything other than spot effects.

 

I'm very familiar with the capacities needed for shows - the same company have been running mobile sound rigs and other show-critical kit from batteries for years, and when one fails it's REALLY bad news - everything I do now has at least one backup in place. Conditions for this show will likely be somewhat less than ideal.

 

We shouldn't have too much RF interference - we're running a selection of mics and IEMs, and inevitably the audience will have phones, but there shouldn't be too much else on the actual site.

 

Again, thanks for the pointers!