dw, I don't know about there being an andavntage or not to using repule over linear. That is just what I have always used. As for charging HV 3000s or Stock Metals SMC Batteries does charge theirs at about 8 amps. He talks about that in the 3000 HV thread and on their website. I have noticed a big difference between charging them at 5 amps and at 7. The higher amps give a lot more punch.