I used a friends brand new pack of fantom HV's and my t35 to charge them at a club meet last weekend. I charged them at 10 amps .09 peak detect and they were simply unbelievable. We also had two new packs of UMH but in my opinion the HV's were far superior. I'm now sure I will be getting the HV's after comparing them against the UMH on the track. However I did find one thing rather surprising, at the end of the charging the HV's they only seemed to be mildly warm to touch, nowhere near as warm as I would have thought. Should the pack be hot to hold in your hand after charging at those sort of numbers.