Looks like you experienced exactly the same problem as I ( and others) did. As per post #3.
I've relegated them to running in some of my scale boats, like navy boats, & cabin cruisers, etc, where the current draw is only around 20Amps or so.

Thanks, this has saved me from making an expensive mistake. I'm glad I looked up some reviews because, as you should never do, I assumed that they would be fine as they are manufactured by Shenzhen Yowoo Electronic Technology Co.,Ltd, who also make HRB.
Here's some marketing blurb

Shenzhen Yowoo Electronic Technology Co.,Ltd was founded in 2012, registered capital is 100,000,000RMB.Our Company is concentrate on manufacture Lithium Polymer Batteries and we are one company that on research,production and sales as one of the high-tech Lithium Polymer Battery manufacturer. Our company has more than 30,000㎡,including office and factories.
    We have some registered international brand,HRB,YouMe Power and Yowoo.We insist on "Devote oneself to offer better power solution for remote control High-tech Field".
    In order to make high quality products,we keep on research and use high-end nanotechnology.Produce and use Grade A cells.We sell our goods to wholesalers,distributors and retailers,of course,we supply best service before ,in and after-sale service.


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Sorry for posting on an old thread...but I had same results as you guys have with my 4500 6s packs. Now could be because of the higher discharge rating... It's allowed to spend that power faster? I mean the packs do come in warm not hot, but was wondering if you guys have noticed performance gain. With my planes, Im not too sure if there was any performance gain, if there was, it was too small to notice..

Wish I had read this post before I bought them from Amazon. These 3300 packs are worse than my very old Zippy 2200 packs. They lose power and don't charge to the advertised capacity. Total crap.

Originally Posted by Tigerman01

Wish I had read this post before I bought them from Amazon. These 3300 packs are worse than my very old Zippy 2200 packs. They lose power and don't charge to the advertised capacity. Total crap.

If you purchased them fairly recently you should be able to return them for a refund!