Help me understand my Emaxx - Page 3 - RC-Monster Forums

BP-Revo · 01.22.2007, 10:34 PM

Is it an programmable/adjustable LVC? If it is, that may be the issue.

Try using profile 2 on the ESC (assuming you have the stock EVX), this eliminates reverse and makes you only have brakes. This should fix the problem.

The issue is that the EVX goes straight into reverse once the motors slow down enough, so any extended brake signal results in reverse.

I have a similar problem with my 18T. My Spektrum Receiver's Failsafe is set to brake slightly, but since it usually takes a second or two to kick in, its enough delay for the Mamba ESC to unlock reverse (its programmed to unlock reverse after the trigger has been in neutral or brake position for two seconds - must be returned to neutral if it was in brake). This usually throws it into a reverse spasm.

Fortunately, I've never lost signal with Spektrum, but I am going to have to re-program the ESC or reset the failsafe to solve the problem (either lock out reverse or set failsafe to neutral).

For now, I dont have to worry since I cut my antenna in half...I'm going to get a new one soon and solder it on.

BrianG · 01.22.2007, 10:35 PM

Do any of these LVCs have a little adjustment on them? Like a SM potentiometer? If so, that would set what the LVC sends to the ESC when it cuts off. Obviously, you want neutral. :)

turbo4 · 01.22.2007, 11:09 PM

Quote:

Originally Posted by coolhandcountry

I don't know how that lvc works.
I have had a lvc go wide open reverse on me.
Well the batts are 7.4 at stand still. But with load could fall to 6v.

You were running lipos on the evx wernt you? Did you not use a lvc? Anyhow I ran the truck some more with the starting voltage at 7.6 and ran it to 7.2v. No reverse experiences this time. I did get a lot of stuttering at a stand still then wide open throttle. I assume this is an overdraw of current that the batts cannot supply?

turbo4 · 01.22.2007, 11:14 PM

Quote:

Originally Posted by BP-Revo

Is it an programmable/adjustable LVC? If it is, that may be the issue.

Try using profile 2 on the ESC (assuming you have the stock EVX), this eliminates reverse and makes you only have brakes. This should fix the problem.

The issue is that the EVX goes straight into reverse once the motors slow down enough, so any extended brake signal results in reverse.

I have a similar problem with my 18T. My Spektrum Receiver's Failsafe is set to brake slightly, but since it usually takes a second or two to kick in, its enough delay for the Mamba ESC to unlock reverse (its programmed to unlock reverse after the trigger has been in neutral or brake position for two seconds - must be returned to neutral if it was in brake). This usually throws it into a reverse spasm.

Fortunately, I've never lost signal with Spektrum, but I am going to have to re-program the ESC or reset the failsafe to solve the problem (either lock out reverse or set failsafe to neutral).

For now, I dont have to worry since I cut my antenna in half...I'm going to get a new one soon and solder it on.

As far as Im aware the lvc is not programmable. Im gonna shoot dimension a email about the issue to see if this is what it is.

coolhandcountry · 01.23.2007, 08:56 PM

Yep. That would be the cause of the stutter. I just ran mine. When it got low
it would let me know. Stutter some to show low voltage.

turbo4 · 01.24.2007, 03:16 PM

Here is what I sent dimension engineering and their response:

Hi, I bought a liposhield for an emaxx monster truck. Im using 2 2s2p
> 6000mah 7.4v packs. When the liposhield \"kicks\" in what should be
> response by the vehicle?
> I\'ve had a few instances where the truck wants to run in reverse on its
> own, or running wide open and it suddenly applies full brakes. The
> functions of the esc are foward/brake/reverse, with a slight delay between
> brake and reverse.
> Also when the batteries are getting low I get a \"stutter\" upon a
> standing start with wide open throttle. Is this a function of the
> liposhield?

Hi Joel,
LipoShield is mainly aimed at r/c planes that have a throttle going from
0-100. When in cutoff, the throttle will slowly be scaled back towards the 0
position, in proportion to the battery voltage. In a car configuration,
you'd typically have 50/50 throttle or 30/70, so the 0 position will
correspond to a full brake or reverse. Unfortunately there would be positive
feedback in this situation - if the battery voltage gets low, the car starts
driving backwards which will lower the battery voltage even more. Basically
if you want to use LipoShield/Cellshield on a car, when you start getting
odd behaviour it means that the battery is drained. We do have an upcoming
product aimed at cars that will have a throttle rollback better suited to
cars/boats - it is in beta testing right now.
Please let me know if you have any more questions!
Best regards,
Hisham Sakr
Dimension Engineering

coolhandcountry · 01.24.2007, 09:01 PM

So it is designed for planes. That explains the reverse for sure. If you see any thing of a stutter or such. End the session. That is what I did on first one
i had.

turbo4 · 01.24.2007, 09:54 PM

For the most part Im not really satisfied with how this lvc is working on the truck. Im likely to take a strong look at the car one he mentioned when availiable.

turbo4 · 02.07.2007, 02:14 PM

If Its cool with everyone, I'm going to continue to use this post for other general questions pertaining to my learning my way around the truck and making changes rather than post all over the place. I think it will better serve(myself,& other new commers) since it will deal with a lot of the basics on making it brushless worthy.

turbo4 · 02.07.2007, 02:27 PM

My next question is the installation of the 3.3 arms, turnbckles, carriers and slidershafts. Ive noticed that there seems to be a front pair and a back pair. Where the turnbuckle mates to the carrier, there is a link, but Im not sure what its called. Some sort of pivot ball. Anyhow one set set(turbuckle links) is mounted in the center of this pivot ball and the other set is mounted in the same fashion except its on one extreme end of the pivot ball. In the pic which end of the truck does this one go on and what is the orientation?

thanks, J.

pinolelst · 02.07.2007, 02:30 PM

I'm a little late in this tread but I see that the LVC is NOT a "car specific " LVC as I had noted in another thread .I have and use the same LVC since it's really the only autodetecting LVC I know of but am looking forward to a true "car LVC" so my truck don't buck like a bronc with burrs under his saddle when the LVC kicks in....:002:

pinolelst

Serum · 02.07.2007, 02:41 PM

Turbo; i think you will find great help in the exploded views you can download from traxxas.com. they are awesome.

turbo4 · 02.07.2007, 03:01 PM

Quote:

Originally Posted by Serum

Turbo; i think you will find great help in the exploded views you can download from traxxas.com. they are awesome.

Thanks, I'll try that.

coolhandcountry · 02.07.2007, 03:06 PM

Quote:

Originally Posted by pinolelst

I'm a little late in this tread but I see that the LVC is NOT a "car specific " LVC as I had noted in another thread .I have and use the same LVC since it's really the only autodetecting LVC I know of but am looking forward to a true "car LVC" so my truck don't buck like a bronc with burrs under his saddle when the LVC kicks in....:002:

pinolelst

You would like to see a smoother lvc like the ones that are built in like quark and mamba.

neweuser · 02.08.2007, 12:56 AM

Quote:

Originally Posted by pinolelst

I'm a little late in this tread but I see that the LVC is NOT a "car specific " LVC as I had noted in another thread .I have and use the same LVC since it's really the only autodetecting LVC I know of but am looking forward to a true "car LVC" so my truck don't buck like a bronc with burrs under his saddle when the LVC kicks in....:002:

pinolelst

The Li Saver that Mike sells is a CAR version. Otherwise, like CHC said, get a esc that has a built in esc....