Originally Posted by
holycaveman
Thanks guys for the replys. I know people who run a single 4s through the evx2. You bridge the bec side battery lead. And use a UBEC.
I've always wondered if this was possible but had never read about anyone who had done it. My experimentation with an EVX2 was brief, came with a truck and was done mostly to see what a dewalt could do.
Originally Posted by
holycaveman
The evx's internal Bec is rated at standard voltage. Like 7.4- 11.1. But by running a UBEC I bypas any voltage running to the internal BEC. Now at this point you throw away the speed controllers voltage rating. It no longer applies. This goes for any ESC. The only thing you need to be concerned about is amps, and overrunning the rpm limit of the esc.
Bypassing the bec side does eliminate that particular voltage restriction on this esc. But there are other voltage restrictions in the esc, namely the capacitors and mosfets. Sure there's usually some headroom built in but there's always a limit that you can't just throw away. Open up a MMM and you'll find 25v rated capacitors, doesn't matter what you do to the Bec the capacitors won't take more than 6s. In the EVX's case 18v capacitors would've provided some headroom for its intended 16.8v but they obviously must've used higher rated capacitors if it can survive 5s and 6s. The mosfets can usually take more voltage but the control circuits that connect to the receiver and tell the mosfets to open and close is anyone's guess.
Yup, gotta be concerned about amp draw. Increasing the weight with more batteries is going to increase the amp draw. How much? Probably about the same amount as increasing the pinion size 3 teeth would. As far as the rpm limit of the esc, that's only for brushless and doesn't apply to brushed motors.
Originally Posted by
holycaveman
Many have run 6s (2 batteries)through an EVX2 using both battery leads. I have read about. So this tells me the esc can run 20+ volts.
I don't get out to many other forums these days so I haven't seen this and couldn't find any in a quick Google search. I did find a post on rcgroups a few minutes ago stating some EVX2's won't run right over 23v. Guy hooked up an adjustable power supply to test and got funky throttle response over 23v. But there's been numerous revisions to the esc and this was one guys test.
Sorry for the long post. And don't take it as picking anything apart I love discussing this stuff. Don't forget to show us what you come up with.