need help with charger

I purchased a 0610i and made a pair or y harnesses (power and balancer) to charge two identical packs. It works great so far. As for a power supply, I found a converted laptop supply on ebay for like 65 or 70 shipped. it was a 12V 30A supply it looks very professional (although it was probably modified by some guy in his basement. My only beef with it was that after 30 minutes of charger 4S at 10A (i use 10,000mAh batteries) the PS was not able to maintain 12V (fell to 11.95 or so) so the charger was making a warning noise. I stopped the charger and told it to charge at 9.5A and it finished off fine and my next charge I stuck with 9.5 and it didn't have any issues. Mind you I was trying to pull ~150 watts of continuous power before it had an issue, but it was able to maintain 135-140 watts continuous fine. You would only be running about 135 watts (I think) so it should work fine (if you go with my cheap power supply idea, using a better power supply you shouldn't have any issues).