No, charging at higher than 1C rates is fine, Flightpowers (Trakpowers) have always been able to take 2C charge rates, but as mentioned, it shortens life span (though it doesn't halve it). Recently cell manufacturers have brought out new LiPos, capable of 5C charge rates in some cases (with up to 3C recommended for maximum life), such as the new Hyperion, Enerland, and Flightpower cells. LRP aren't going over the top with the 3C suggestion, it's just finding a charger to charge at 15.9A that's more the problem. 10A isn't even 2C so is safe, and won't really reduce the life span.
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