I have an old D2 enlarger that, so far, I've been using without a power supply unit. I was just given a Beseler enlarger that was apparently used without a power supply unit. Given that I now want to use an electric space heater in my darkroom, I think it's time I begin using something to regulate things. So far, I've not found anything on eBay. A friend told me he knows someone who uses a car battery charger that has a 110 outlet on it. Would this really work? Any other ideas?