I bought 2 Venom batteries for my Yuneec Q500 4K last year. They have both swelled and I no longer trust them. One battery swelled so much it no longer fits in the battery bay. Both were treated properly, never stored for long with a full charge. The 2 Yuneec brand batteries continue to work without swelling and offer just a little bit less flying time compared to new. All four batteries were treated in the same fashion. I won't buy any more Venom batteries due to the problems I've had. Before the Venom cells became unusable, they offered about 2 extra minutes of flying time compared to the Yuneec brand cells.