Believe me there's no limit for asking a question here. We are very helpful, knowledgeable, and friendly forum dedicated to e-scooter mods. I got here only few months ago, at that time I didn't even know what overvolt is lol. But with their guidance I managed to did my first light mods of e300, and my last successful project was e-scooter with brushless motor, vesc, and lipo battery that I really love.
But at the same time, we're also a very small group that most of the question is answered by our Rob, laundydude, and few people only.
Sadly members that gained a knowledge and successfully did the mods didn't participate or share the info to the other new members.
For circuit breaker or battery disconnect switch, basically you have 2 inexpensive yet reliable options. One is 200A max and the other one is 100A. The 200A is more robust and has key http://www.ebay.com/itm/Auto-Battery-Di ... Qq&vxp=mtr
. The big drawn is they're big and clunky. So unless you're running a high amp and high voltage, I would recommend you to 2nd option that I personally use which is 100A.http://www.ebay.com/itm/Car-Truck-Boat- ... e2&vxp=mtr
The size is notably smaller and more compact. I use it on my 10s lipo system (around40v), 60A with no problem at all and very reliable. If I were you I'll buy this one unless you really need that key for security reason.
Here's mine on my scooter