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-   -   been having a problem with my buggy (https://www.rc-monster.com/forum/showthread.php?t=29643)

Hyper-5 03.26.2011 03:09 AM

been having a problem with my buggy
 
hey, l've been having this particular problem with my buggy for a long time, the problem is, when l give it full throttle ther is a delay the the car kicks in, BUT when l try 2 turn the car or brake when it's in full throttle the car wont turn or break for a number of seconds, there is a delay in the when giving it a hit. if l go easying on the throttle it's fine. ldk if its not enough power going through the esc or my burst rate is low on my batter (20c). Can anyone help me out here?

suicideneil 03.26.2011 12:22 PM

What esc are you using?

If its an MMM or MMPro ( or MM even ) then upgrade the firmware to the latest version ( v1.30 ), or downgrade it to v1.24- much more stable and no weird throttle issues. If it isnt a castle esc, then the original question stands + what is the rest of the setup?

DrKnow65 03.26.2011 12:24 PM

Interesting problem...

Can you tell me what happens if you set the LVC to 3.7v per cell? If the car hits the LVC with a freshly charged batt within the first few minutes of the run, I'd say it's time for a better batt :-) If it doesn't hit the LVC right away the problem probably is not the battery.

Does the car do the same thing when held up off the ground?

BrianG 03.26.2011 02:05 PM

Setting the LVC for 3.7v/cell is basically telling the ESC to reduce and/or cut power at that level. 3.7v is the nominal level for lipo so what's happening is as soon as you apply throttle, the voltage dips to that (or lower) level. Try setting it to 3.2v/cell, or maybe 3.3v and try again.

simplechamp 03.26.2011 04:13 PM

I would say 20C burst rating on the lipos is too low also. You can get a lagging effect from that.

From the Castle Creations FAQ:

5. My vehicle acts like it has "turbo lag" (poor acceleration/punch for the first few feet or yards, and then it "kicks in").

Make sure you're using high quality batteries, and a battery connector capable of high amp flow (75A minimum!)…we recommend our 6.5mm CC Bullets, Deans Ultra connectors, or the Traxxas TRX connectors. This behavior is very typical of a battery pack that is having difficulty providing the power your vehicle/system requires for top performance. The faster the top speed of the system, and the more traction available, the harder the batteries have to work to accelerate the car.

The lowest packs I personally use are 20C constant, 30C burst, and once they need to be replaced I definitely plan on getting no less than 30C constant, 40C burst.

Hyper-5 03.26.2011 06:37 PM

my current setup is Xerun 150A ESC, speedpassion motor 3.5t, and one 11.1v 8000mha 20c lipo, even when the car is off the ground it still does this problem. when l give it full throttle when stationary it sometimes goes full throttle nd sometimes its half the throttle, then when l try to steer or brake, it wont let me and l have to wait for about 3-5 second for it to respond, when doing my speed runs and hitting 99km/h it frightens the shit out of me when it delays in brakeing or turning. l've crashed once under a car and bent the chassis because of this issue

DrKnow65 03.26.2011 07:04 PM

Quote:

Originally Posted by BrianG (Post 402529)
Setting the LVC for 3.7v/cell is basically telling the ESC to reduce and/or cut power at that level. 3.7v is the nominal level for lipo so what's happening is as soon as you apply throttle, the voltage dips to that (or lower) level. Try setting it to 3.2v/cell, or maybe 3.3v and try again.

Yah, the idea was to keep the ESC from pulling the battery down to see if that would help the BEC stay up. Like asking the batteries for less power... not for average running, but as a troubleshooting measure :tongue:

brainanator 03.26.2011 07:35 PM

Maybe try running a BEC or slap a capacitor on the receiver? Maybe it isn't getting enough power? I'm sure someone with more experience in this kind of matter can either support or refute my suggestion :)

BIG-block 03.27.2011 06:59 AM

I had very similar issues when the weak BEC on my MMM was causing my Rx to brown out. Once I fitted an external BEC all problems went away. I think you might be having problems with the BEC being unable to supply the demand from the servo and the Rx but if possible also try to eliminate the Rx by changing to another one if you can. Either way a decent BEC is only about $20 so it isn't a huge layout. There is also a slight chance that your servo might be causing issues. Sometimes a faulty servo can cause the BEC to go into shutdown if it causes the it to overload. It's just going to be a process of elimination.

Also what brand are your batts? 3S 8000mAh 20C??????

Hyper-5 03.27.2011 07:42 AM

can u send me some links to some BEC's cause l don't know what they are

BIG-block 03.27.2011 07:53 AM

Here is a page that will answer all of your Qs regarding BECs. CLICK HERE. I use the small blue one on a few of my cars with no issues at all. I got to say that it's great bec and pretty solid. I wish Castles internal BECs have the same strength as their external ones. :whip:

BIG-block 03.27.2011 07:57 AM

Quote from Castles web site.

Quote:

This product may contain chemicals known to the State of California to cause cancer and or birth defects or other reproductive harm. Do not ingest this product, it won’t make you any faster.
:lol::rofl::lol::rofl::lol::rofl:

Hyper-5 03.27.2011 07:59 AM

lm not looking for spped, but l want somthing to stop this problem, what is a BEC anyway?

BIG-block 03.27.2011 08:12 AM

What? Did you click on the link in my post? Everything you need to know about what a BEC is and does is on there for you to read, My last post was just a quote from a little joke that Castle made on their site. It has nothing to do with a BEC.

suicideneil 03.27.2011 05:20 PM

BEC = Battery Eliminator Circuit

It is used to power the rx and servo if the built-in BEC on the esc isnt strong enough or doesnt have one at all.

Might be worth recalibrating the esc to the tx too if you havent tried that yet, make sure the throttle trims are at neutral & there are no weird expo/ epa settings etc.


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