I have a "12vDC 500ma" wall power supply, but when I checked it, it comes out 18.2v, so I assume that means its unregulated. I'm building a small SLA battery charger and need 17-18vDC to come in, I was going to use a 12.6v 300ma transformer, then a bridge rectifier. Would the unregulated "12v" power supply work alright?