I am looking at a few different chargers to get into the lipo world of offroad electric 1/10 scale. I liked the idea that this charger does not need a power supply, but I had someone tell me that the charger took forever to charge because the charger would only charge at a certain amperage. Is this true or can you select up to 4 or 5 amps to charge let's say a 7.4 25c 3800 pack? Any feedback would be appriciated about this charger as I am looking to make a purchase in the near future.