My local hobby shop guys said that the 400oz servo is more than enough with 1A without a BEC. Do you guys think this is true? I've finally ordered a sport with the recent ebay sale and I already have the servo plugged into another crawler.
As long as it won't harm my ESC then I am going to plug it in regardless, but I just want to know if I need to order the Traxxas BEC kit.
What kind of issues will it cause? I'm assuming it's because it's pulling more power than the ESC can actually give?
Yup...
The circuit protection between the ESC's BEC and the stock servo is in the servo itself in the form of a tiny little fuse, aftermarket servos do not have the fuse. With just stock electronics (stock servo is rated at 120oz) the servo can pull too much amperage, and sometimes the fuse does not pop when it should causing the ESC's BEC to fail, killing the ESC. So, if you put a 400oz servo in, and put any real load on it, the 1A BEC in the ESC will fry. In short, yes, you need/want a BEC.
You have a good number of options, and it really depends on how much adjustability you want and how comfortable you are futzing with your electronics. I normally use CC BECs, they have adjustable voltage and allow me to set things up the way I want, but they have to be soldered in. Also, the $20 version is not waterproof, so it has to be put in an RX box, or conformal coated (I conformal coat). Traxxas does offer a plug-n-play BEC that should satisfy your needs, its a little spendy, but you basically just drop it in and you are done.
https://traxxas.com/products/parts/2262
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