Powering Pocket Par

Barry Cheong · Aug 28, 2004

I've seen it been done but didn't get to check out the details of all the connections. How would you power an HMI (125watts) pocket par off a battery belt? I know most battery belts have an XLR connector on it but I'm pretty sure the HMI ballast doesn't have an XLR connector? Is there an adapter of sorts? Or a certain battery belt to get?

Thanks.

laurent.a · Aug 28, 2004

What you've seen must have been a 125/200 w HMI torch, that is designed for being supplied either on mains or battery. It has 2 different little ballasts according to the supply you work with. I don't know much about other devices in this range of power (though there certainly are...) The one I have (LTM) has different lenses like a cinepar, but smaller (fresnel, "nid d'abeille"...) I don't know about making your own torch and building a ballast that you can supply on a battery from a mains powered HMI and since this torch could be what you're looking for... You should find it in any light rental, or even some "news" agencies...

You can put either a 125 or 200 W lamp, and can graduate it.

About the connections : the battery I have with this torch is not XLR linked. it looks a bit like it from little far but it's not. The RCA cables used for power supply are more commonly 4 pins than 3 pins XLR actually and you usually have pin 1 on neg, pin 4 on plus.

The HMI torch is supplied 24 V, so you can use many different types of batteries since you have the good connector. If you need a good amount of energy, you can even use truck batteries (for shooting on a boat, for instance...)

This torch is of very great help. I lit an entire short film in exterior with this one, as we were shooting somewhere deep in the forest where no power supply was possible to set. It's a great fill-in in such circumstances.

Barry Cheong · Aug 28, 2004

Hi Louis,

Thanks for the reply. I know what i saw for a fact was an Arri Pocket par and I'm pretty sure it was a 125watt model. How would you be able to power such a device off a battery belt? From what I can tell the Arri ballast has only a standard edison plug right?

Thanks again.

Barry

Barry Cheong · Aug 29, 2004

Just a follow up...I downloaded the Pocket Par guide off of Arri's website. It appears what I would need is a DC ballast...as you mentioned Louis..("It has 2 different little ballasts according to the supply you work with."). Sorry it didn't register to me that there are 2 kinds of ballasts...AC and DC ballasts. The DC ballast has two cables coming out of it which look like 4 pin connectors for a battery belt. The AC ballast has a connector for a standard edison power cord.

Thanks again!

laurent.a · Aug 29, 2004

Hi, I guess it's me (Laurent) you're replying to, as I don't see any Louis around here

...

Ok then , it's an arri torch you have, not LTM. I don't know this torch, but, as your problem seems to only be a powering one, I guess I figured out what you said and try to do.

Since you found a documentation on this arri torch, I guess that you'll find a few informations you might need.

May be there is a specific battery that arri provides (should be) that you could rent with the projector, and DC ballast.

Otherwise, check voltage and needed capacity (Amp.Hour) as well as connecting plug and just any battery with the required specifications would fit. As I told you, if it's 24 V , you could even use a truck battery.

Mind the polarity of the 4 pin plug (usually 1-, 4+) and connect a 4 pin plug on the battery (solder it).

Mind that some of these torches work on 30 V...

About capacity : you can always use a battery that delivers more than the required capacity, never put a battery that is delivering less.