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-   -   Need a new BL-Controller for my Savage (https://www.rc-monster.com/forum/showthread.php?t=2324)

Dafni 02.14.2006 08:26 AM

Going into full reverse if you keep holding the trigger is exactly what it is supposed to do. Just release the trigger when the truck has stopped, it's easy. It won't go into reverse if the truck is still rolling.

Just release the trigger.

btw, I never use full brake anyway, it would flip my trucks over. (set EPA)

Attila 02.14.2006 09:08 AM

Quote:

Originally Posted by Dafni
Going into full reverse if you keep holding the trigger is exactly what it is supposed to do. Just release the trigger when the truck has stopped, it's easy. It won't go into reverse if the truck is still rolling.

Just release the trigger.

btw, I never use full brake anyway, it would flip my trucks over. (set EPA)

NO, I would expect that the controller acts like in this description (it's from MGM):

CAR mode forward / backward [A1]:
If the car is at standstill, then by moving the throttle from neutral the car will go backward or forwards. If the car is moving then by moving the throttle backwards the car will brake. The brake is proportional, that means the further the throttle is from neural the more intensive the brake is. The intensity of braking in the max throttle position may be set in parameter "B". When braking the car will stop, and not start moving backwards until you move the throttle to neutral and then again backwards. Connected braking lights are turned on when braking.

-- Dave

Dafni 02.14.2006 09:33 AM

Ah, I see. That's the "double throw reverse"! Some ESCs have this. They only go into reverse if you go to neutral first.

I prefer the "single throw" types, such as the EVX or the BK controllers. If you found this describtion on a MGM product, I would guess they'll act that way.
The downside is well known: if your car is still rolling, and you want to brake again, it goes into revers too. That's why I prefer the single-throw types!

DAF

coolhandcountry 02.14.2006 09:41 AM

They change the programming some to. I don't know if it is a double throw any more. It may still be a setting option in the controller.

MetalMan 02.14.2006 07:32 PM

Quote:

Originally Posted by Attila
NO, I would expect that the controller acts like in this description (it's from MGM):

CAR mode forward / backward [A1]:
If the car is at standstill, then by moving the throttle from neutral the car will go backward or forwards. If the car is moving then by moving the throttle backwards the car will brake. The brake is proportional, that means the further the throttle is from neural the more intensive the brake is. The intensity of braking in the max throttle position may be set in parameter "B". When braking the car will stop, and not start moving backwards until you move the throttle to neutral and then again backwards. Connected braking lights are turned on when braking.

-- Dave

I would actually disagree with MGM's statement about this. Just this weekend I was doing speed runs with my Rustler and MGM Compro 12012 (newest version as far as I am aware) with 4s Lipo and a Feigao 540 12s. Since its BEC is putting out the full battery voltage (I know, it's strange) I have to use an external BEC. The XUS Hobby UBEC induces glitching, so my range isn't the greatest. Anyways, to maximize my acceleration distance I had to brake as late as possible. Most of the time when I hit full brake when going full throttle, it resulted in the tires spinning in full reverse while my car was going 50mph! Obviously that isn't a good thing, and was very annoying. I've also noticed that the MGM is finnicky in general. Sometimes going from a low throttle position to neutral causes it to do the brake thing (no "freewheel") like the older versions did, even though I have it set so that it will "freewheel".

Now to the likes: fully adjustable acceleration and braking, and a LVC for Lipos that kicks in at 3.1v/cell with a hard or soft cutoff, or no cutoff at all.

Dafni 02.15.2006 03:09 AM

Hmmm, metalman, the LVC is nice. Very nice indeed. But the going into reverse is bad! Might tear your rusty in two one day :026: And the BEC giving the batt voltage...well, what can I say. Strange.

Freewheel is a must for me, too.

Thank you for the honest report!

Attila 02.15.2006 03:19 AM

Quote:

Originally Posted by MetalMan
... Most of the time when I hit full brake when going full throttle, it resulted in the tires spinning in full reverse while my car was going 50mph! Obviously that isn't a good thing, and was very annoying. ...

Sounds as if your controller is in Boat mode:

"BOAT mode forward / backward [A2]: ...The direction of motor revolutions is reversed immediately upon moving the throttle the opposite way." (MGM)

-- Dave

Dafni 02.15.2006 03:36 AM

I doubt it, Attila, like I know our Metalman.
This problem was mentioned by other users, too.

Anyway, did you get the double-throw VS single-throw idea?

Attila 02.15.2006 04:42 AM

I was in contact with BK yesterday. I asked them about the "brake/backward-problem". Here is what BK answered (short version):


"Breaking is a short-out of the motor. When you are breaking all phases of the motor are under positiv voltage. That's also the reason why MGM controllers are burning some times.
When you hold the trigger in break position for more than 1.8sec. the stress peaks are so high that when switching to forward mode the motor could blow up.
That's the reason why 99% of the (racing) drivers like the behaviour of the BK controllers. Nobody would ever break for more than a second."


Ok, maybe a "racing driver" would not break longer than a second. But I driving a Savage and I am bashing for fun and not entering a race contest...

-- Dave

coolhandcountry 02.15.2006 08:52 AM

How does a person supposed to stop the truck at 50mph in less than a sec?

MetalMan 02.15.2006 09:53 AM

Quote:

Originally Posted by coolhandcountry
How does a person supposed to stop the truck at 50mph in less than a sec?

They don't!

Quote:

Originally Posted by Attila
Sounds as if your controller is in Boat mode:

"BOAT mode forward / backward [A2]: ...The direction of motor revolutions is reversed immediately upon moving the throttle the opposite way." (MGM)

-- Dave

I'm pretty sure it was in car mode. With my previous MGM controller, I ran in boat mode and it wasn't good. The braking had a whole different feel.

Attila 02.15.2006 12:21 PM

Has anyone ever had (or heard of) problems that a MGM controller was burning (or melting)?

(BK said: "That's also the reason why MGM controllers are burning some times.")

-- Dave

Attila 02.15.2006 06:23 PM

Quote:

Originally Posted by MetalMan
I'm pretty sure it was in car mode. With my previous MGM controller, I ran in boat mode and it wasn't good. The braking had a whole different feel.

@metalman:
I have read the manual of the MGM controller. Maybe you should doublecheck your settings. I couldn't believe that your controller is in car mode and act like this.

-- Dave

GriffinRU 02.15.2006 08:30 PM

I will say BK sales people are not correct...

If BEC on MGM controller outputs full battery voltage, then BEC part is damaged. See my earlier report on MGM's BEC failure.

As far as updated versions of MGM ESC, I haven't had such problem yet. But I was not using BEC from the very start either (memories of blown servos...).

You should be able to apply brakes as long as you want, motors back EMF should be well below FET's voltage limit. But if you have noisy/glitches in receiver part then you signing for disaster yourself. Use good power connectors and good UBEC (most times bad capacitor on UBEC or ESC part can create problems).

Artur

MetalMan 02.15.2006 09:58 PM

I have taken the MGM out of my Rustler for now, since I have to use an external BEC (that causes glitching), which is bad for speed runs. If I do put it back into my Rustler, I can try again. It might be used in my 1/8 buggy, but if it is, the brake strength will be pretty low (along with EPA lowered).


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