ok didnt realize you had a 12 volt powerbar. ill have to check on that. ive got a couple of pc fans but they are 12 dc. i can run them off a motocycle battery trickle charger
I wouldn't use any battery charger for a supply, it's not a steady source, more of a pulse and have a lot of noise, get a PC power supply, depending on how many watts you can use a wall transformer. Especially if you are just running a couple 12vdc pc fans, just wire them up to a wall transformer.