Studio Flash Explained:
Battery Powering of Studio Flash

Battery Powering of Studio Flash
In the past, using high-powered flash systems in the field required the photographer to buy two separate lighting systems: an AC powered one for the studio and a battery powered one for location use.

In the past few years, it has become practical to power AC studio flash systems with battery power converters that produce 120 VAC. Thus, the photographer can easily take his entire studio setup anywhere without buying another lighting system. But there are some special considerations in doing this:

Professional flash systems are somewhat unique in their power requirements and cannot be used with the ubiquitous “Modified Sine Wave” or “Quasi Sine Wave” power inverters often sold as accessories for cars and boats. These inverters are notorious among pros for damaging either the flash units or the inverters themselves, and most of these won’t work at all.

The reason is that studio flash units convert AC power into high voltage for the flashtube using capacitor based voltage multiplier circuits. These circuits require a Pure Sine Wave similar to what you receive on your household powerlines. Thus, proper operation of flash units demands a Pure Sine Wave Inverter from a battery supply as well.

Beyond this, studio flash units exhibit another powering obstacle. While their long-term average power requirements aren’t severe, there is a very high initial inrush current to deal with. This can be from 16 to 60 amps or more. While this does not usually cause household breakers to blow because it is of short duration (like a motor-starting circuit on a refrigerator), conventional power inverters often cannot supply this sort of current and simply shut down.

For reference, conventional circuit design would require on the order of a gigantic 7000W inverter and a 100lb battery to supply this much current directly. Indeed, many photographers have lugged gasoline-powered generators around to fill these requirements.

In order to create a battery inverter system more in tune with the needs of the traveling photographer, we have taken a different approach to things in our pioneering line of Vagabond™ Portable Power Systems. Each Vagabond™ model uses a Pure Sine Wave inverter of modest size and power that is capable of limiting its output current to a safe value during the initial stages of recycle instead of shutting down. As the inverter delivers current-limited output on a nearly continuous basis, this allows a single battery and inverter to power multiple studio flash units.

The requirement of the flash units attached to such an inverter system is that they be capable of operating in the presence of the dramatically lowered AC input voltage necessitated during the initial recycle period (“brownout”). All Paul C. Buff™ flash units are fully compatible with these conditions as are most competitive studio flash products. But in some digitally controlled flash units, the designers have not allowed for this sort of operation and the microprocessors used can “crash” under brownout conditions. This can cause such units to work improperly with small Pure Sine Inverters, or to not work at all.

The Vagabond™ systems (Vagabond Mini™ Lihtium and Vagabond II™) are designed specifically for powering Paul C. Buff, Inc.™ products and we cannot make any claim for suitability with products from other manufacturers, nor can we accept any liability for any damage that might be caused to such equipment. We will, however, warranty the Vagabond™ systems themselves as well as any Paul C. Buff, Inc.™ equipment they power.