Bullet ST Flux isn't steering well with 3S Lipo, any servo advice?

[tolgahan]

Hey ?‍

I just upgraded my Bullet ST Flux with DXF Power 11.1V 3s 5200mAh 50C Softcase Lipo battery but the car is not steering when going in high speed which I assume due to it's power from the battery and the servo being weak for such power.

I have a servo sitting in my drawer that I probably purchased years ago and didn't even unbox. It's Savöx SB-2271SG. Can I use this servo for this car and will it work with 3S Lipo or are there any better servos that I can fit into this car?

For the battery, that was the best I could find but I actually wanted to go with 7000+ mAh but they were too big to fit into this car's battery box. Are there any better 3S Lipos that I can buy for this car?

Thanks!

 

[olds97_lss]

Servos are typically driven from the BEC in the esc. What esc do you have? Most RTR's run a 6V BEC to the receiver (which powers the servo), so it's irrelevant what is plugged into the ESC itself. What matters is the current capability of the ESC for the BEC circuit as to how well it will power a stronger servo.

That servo is a pretty high current servo:
6A stall @ 6V, 7.4A stall @7.4V

Which means, if the servo is stopped, or strained a lot, it's going to pull 6-7.4 amps, depending on the voltage available.

If it's the Flux EMH-3S, it only has a 6V/2A bec in it. So it likely will not power that savox very well at all. You would need an external BEC. Castle has a $20 10A one that would likely be enough:
https://www.amazon.com/Castle-Creations-Bec-Switching-Regulator/dp/B000MXAR12

I've run one of those, but I didn't push it all that hard. Probably put a 4-5amp load on it and it did far better than the 3A BEC in my old HPI esc did.

 

[tolgahan]

Servos are typically driven from the BEC in the esc. What esc do you have? Most RTR's run a 6V BEC to the receiver (which powers the servo), so it's irrelevant what is plugged into the ESC itself. What matters is the current capability of the ESC for the BEC circuit as to how well it will power a stronger servo.

That servo is a pretty high current servo:
6A stall @ 6V, 7.4A stall @7.4V

Which means, if the servo is stopped, or strained a lot, it's going to pull 6-7.4 amps, depending on the voltage available.

If it's the Flux EMH-3S, it only has a 6V/2A bec in it. So it likely will not power that savox very well at all. You would need an external BEC. Castle has a $20 10A one that would likely be enough:
https://www.amazon.com/Castle-Creations-Bec-Switching-Regulator/dp/B000MXAR12

I've run one of those, but I didn't push it all that hard. Probably put a 4-5amp load on it and it did far better than the 3A BEC in my old HPI esc did.

I just have the stock parts so yeah, it’s Flux EMH-3S.

So I should change the ESC as well with this Savöx?

 

[olds97_lss]

I'd get a BEC. Cheaper and more effective. You'd have to spend a decent amount of money to get an esc that puts out 5A constant. Most 1/10th ones put out 3-4A. 1/8th put out 4-6A. Some do more, but that's what I've seen. Once you start adding power hungry servos, relying on the BEC in the ESC isn't the way to go.

 

[tolgahan]

OK, I ordered the Castle BEC from Amazon. I’ll put it with that Savöx servo and see how it goes. Thanks!

 

[tntpoof]

You will find that the castle 10 amp bec will fail with heavy use.. Id get a backup just in case.

 

[olds97_lss]

You will find that the castle 10 amp bec will fail with heavy use.. Id get a backup just in case.

Heavy as in extended use or heavy as in running a 9.9A draw on it constantly?

Just curious as I have a couple of them, had intentions on using them both but only used one for a while in my revo. I probably didn't put more than a 5A load on it when I used it for the few months I had it.

Ended up swapping the esc I was using for one that had a better bec built into it.