I was wondering if anyone had ever tried using one of the consumer power packs, such as this one that you can purchase from automotive and similar retailers to power their strobes in the field? I don't have a lot of requirement to do this, but and while I would like the capability, I'm hesitant to pay the price for a Buff or Profoto power unit (simply because I wouldn't use it enough to justify the cost). These seem like they might be a reasonable alternative for light-duty field use. Thoughts? Experience?