I have the parkzone corsair. It's easy to know when to bring it in, it buzzes at you. You will hear the engine start to surge back and forth and you will definitely notice the loss of speed. As soon as that starts, i bring it down. You can time it, then you will have an idea of how long it actually lasts. The parkzone charger isn't that bad actually, it has a charge rate select and audible alarm. Only drawback is that you only have the cig lighter power connector. If you haven't ordered your overpriced charger yet, check this out. http://www.hobbycity.com/hobbycity/s...lancer/Charger It comes highly recommended from the electric forum and other guys that fly the corsair. I have one and it works great and has a very nice display. These batteries are the exception to the rule of you get what you pay for. http://www.hobbycity.com/hobbycity/s...0mAh_3S1P_25C_ I have one too. They are also highly recommended in the same forums. Here is the Corsair forum. http://www.rcuniverse.com/forum/m_7590470/tm.htm