sidewinder esc and 4s?
 

i am in the process of getting a new esc for my rustler and i have been looking for something in the $50-$70 range. the sidewinder seems like a great candidate except for one thing.

i know the MM can be run at 4s with no issues with an external bec. is there any reason i can't run a sidewinder on 4s with a bec on a rustler with a 2200-2600kv motor geared for 40-50mph?

It will work :party: I was running a Sidewinder with 4s and CCBEC on a Novak 17.5 (~2200 kv). There was quite a bit of cogging at startup due to the gearing but once rolling it was pretty smooth. Now running a MM Pro though.

The official answer is no.

The Sidewinder was not designed for running above 3S. Some percentage of Sidewinders will NOT work at all on 4S. The BEC has a maximum voltage of 16.0V, 4S is maximum around 16.8V. Some percentage of the BEC chips detect an "overvoltage" condition, and shut the BEC output off.

i was planning on using an external BEC. can 4s be done WITH an external BEC?

He's saying "maybe". Even though you disable the internal BEC, all that does is keep it from powering devices external to the ESC. It still is "on", and apparently, the IC used shuts down at 16v in some cases.

so, that's a no-go if i were to get a new sidewinder? so, the older sidewinders can do 4s, but the new ones can't?

anyone got an old spare sidewinder hanging around? a MM maybe, if the price is low enough?

btw, thx for the help Pdelcast. it's nice to see that you care enough about your customers to help them in this forum. i have a MMM and it's the only brushless esc that i've owned that hasn't smoked or died. i was going to get a cheap-o chinese esc, but after getting that MMM, i am wanting a mamba esc for my rustler vxl as the vxl speed control died. (for the third time)

It doesn't really have anything to do with old vrs. new. They haven't changed, it's just the luck of the draw...

so, why is it that some work and some don't? shouldn't they all have the same internal parts?

Again, they do all have the same part. The part is rated for 16.0V. 4S Lipos are 16.8V. Some percentage of the parts will still work OK on 16.8V, as the overvoltage has about a 10% margin of error (tolerance,) but some will not.

Thanx!

Patrick

You only need the external BEC to power the radio and servo. The SW BEC circuit is still powering the internals of the SW. If the chip shuts down then the SW gets no power. So basically if the SW arms then it should work, if not then it's one of the chips that are within spec and are shutting down due to over-voltage. Not to mention 4s will void the warranty (right?).

Patrick, do the regular MM ESCs use the same BEC chip? Because every MM I've tried on 4s (external BEC used of course) arms fine on 4s.

No, the MM ESC uses a different chip that is rated up to 28V input. It's a much more expensive chip than what is used on the Sidewinder.