ghetto Vagabond

[Big Mike]

I made my own ghetto Vagabond (portable battery for powering a studio strobe).

Not really anything to 'make'...I just bought a pure sine wave inverter and a battery and hooked them together. The idea was to have something that is lighter than the Vagabond, which is something like 18 lbs. I haven't put mine on a scale, but I'd guess that it's less than 10lbs.







I bought a tool bag to hold it. I like the bag because I can store the battery charger in there and also coil up the power cord when using it. It could also keep some rain off of the electronics if it starts to rain. I took the bag over to the fabric factory here at work and had them put some grommets in the ends for ventilation.





So how does it work? Fairly well so far.
I plugged in an AlienBee B800 and it fired it over and over again with pretty good recycle time. I didn't bother to see how many shots it would take to kill the battery...I'd guess at least a couple hundred.
One issue is that the inverter gives me a beep every time the light is fired. I'm guessing it's a low voltage warning. It beeps longer for a full power shot and just barely beeps for minimum power. Not something I'd want to have beeping during a wedding ceremony but perfectly fine when used outside.

I tried a B400 and it still beeps throughout the power range.
I tried an old Medalight 150Ws strobe that I have. It worked without beeping but the recycle time was a lot slower than with the AB lights.

Another thing was the electric fan in the BEEs. When the strobe fires and it draws all that power, the fan slows right down...then gradually speeds back up as the light recharges. I think some studio strobes have fans that can be turned off, or are on temp sensors and only turn on when needed...I wish mine were like that.

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[jcblitz]

Total cost?

[photo28]

The title mislead me completely. I was expecting to see a homeless guy with some ghetto clothes on and a radio over his shoulder
Interesting though.

[RyanLilly]

My question is weather the low voltage warning is coming from the primary or secondary side of the transformer. Either your strobe is exceeding the available current from transformer, or the inverter cannot draw enough from battery in order to sustain the current draw. The paper work should give peak ratings for the inverter and strobe, but often the ratings given have no bearing on reality. My guess is that the battery you are using cannot keep up with the spike in current draw when the strobe is fired. A simple test would be to hook up the inverter to a car battery, they are designed to have enormous peak output for a short duration(when you start your car). If my thinking is correct the inverter will not beep. If the beep continues than the inverter is slightly to small for the application, though i practice it will probably work just fine. You could always add a second battery in parallel to increase the available current.

[Big Mike]

Total cost?

The inverter was about $150 (give or take) with shipping. The battery was $25. I also bought a good quality 3-stage battery charger, which is supposed to be a good idea of SLA batteries...it was $60. So all in all, it came in a little under the cost of an actual Vagabond.

I actually think the Vagabond is a better option for the money, as long as you don't mind the weight. My plan is to actually hang this off of a light stand so that the stand/light/battery is all one unit that I can grab & carry with one hand.

Ryan,
It's a 300 Watt inverter, which I believe should be easily capable of supplying power to the strobe. I believe the problem is the current draw on the battery.
I have a friend who build one of these as well. He used a better quality inverter & the same battery...he also measured the drop when a strobe is fired and it just barely fell within the specified limit for the inverter. As you said, car batteries are made to take a huge peak draw but this little battery is not.

[Mastino]

Mike, just you you a 1 farad capacitor and put it between the battery and the inverter. Low cost and not much weight. That should prevent the beeps and save some load on the battery.