RCCrawler Forums

kwkride · 03-25-2008, 10:50 AM

Hey Guys,
I've got a couple of questions. First of all, I seem to have some glitching going on with my truck. It only happens when the truck is more than about 15 ft away from me and only when I am turning and backing up. The steering servo works fine, but the truck does not want to back up. I have to keep playing with the trigger to get it to move a little, or move closer to the truck. Could this be because I've got the antenna just tucked into the chassis instead of sticking up in the air?

The other issue that I'm having is with run time. I purchased a small (2/3a 1400mah) 6 cell pack to cut down on weight. It works great, but I only get about 15 minutes of run time. Is this normal?

Thanks,
Jim

Wheely King
Stock HPI receiver 27mhz
Novak XRS ESC
Integy 65t motor

kwkride · 03-25-2008, 11:00 AM

I just noticed this information about my servo.

__________

This is the Futaba S3305 High Torque, Metal Gear Servo.
per Futaba this servo is approved for use with NiCd batteries ONLY!

This servo can produce high-current draw from your batteries. If using NiMH or LiPo batteries, make sure they are capable of delivering sufficient amps.
__________

Could this be causing my issues? I didn't realize that the servo could require a specific type of battery.

Jim

JavelinSST390 · 03-25-2008, 11:21 AM

I don't know about your servo, if that would be the problem or not. Although I can't imagine why there would be a warning like that. NiMh and Lipo packs are capable of WAY MORE output than a standard NiCd pack. That all seems backwards?

Are you running your antenna through the body still or did you hide it underneath? I hid mine underneath the body (actually just wadded it up and put it in the bag with the reciever before I zip-tied it shut.) And it works fine until the batt's on my Tx start getting low. Then it starts glitching pretty bad.

I don't know if that helps or not. Gerame is the guy to talk to on this one.

BTW, Those gears I ordered STILL haven't come in yet. I'm hoping they'll be here by thursday because I need to go to town anyway for my daughter's doctor's appointment.

sparky0068 · 03-25-2008, 12:16 PM

Try running tyour ant. sticking out of your body if this fixes the glitching then you know your problem.

On the battery problem you could try going back to the standard sub-c 6cell packs and gain run time at the cost of weight. My son runs his modded king with sub-c 6cell and he gets about an hour with a 3000mah ni-mh.

My new truck that I am building will run sub-c's just for the run time.

Are you still running the Jolt esc?

kwkride · 03-25-2008, 12:44 PM

Quote:

Originally Posted by JavelinSST390

BTW, Those gears I ordered STILL haven't come in yet. I'm hoping they'll be here by Thursday because I need to go to town anyway for my daughter's doctor's appointment.

No problem, I haven't stripped the original ones yet!

Jim

kwkride · 03-25-2008, 12:46 PM

Quote:

Originally Posted by sparky0068

Try running tyour ant. sticking out of your body if this fixes the glitching then you know your problem.

I'll try that, hopefully that fixes it.

Quote:

Originally Posted by sparky0068

Are you still running the Jolt esc?

No, I fried that the first day. I have a Novak XRS in there.

Thanks,
Jim

sniders1975 · 03-25-2008, 04:43 PM

hey jim i run that same servo & have no problems with my batteries!!

kwkride · 03-25-2008, 07:45 PM

Quote:

Originally Posted by sniders1975

hey jim i run that same servo & have no problems with my batteries!!

Thanks, I'm wondering also if maybe I need to put capacitors on the motor . . . .

Jim

sparky0068 · 03-26-2008, 12:53 AM

caps are a must

kwkride · 03-26-2008, 06:23 AM

Quote:

Originally Posted by sparky0068

caps are a must

That makes sense, since the truck doesn't do this with my 17t motor in it. That motor has caps on it already. Any suggestions for specific caps? I think I read .047mf?

I also noticed yesterday that the cell selection switch on my charger had been bumped and it was on 5 cells. I wonder if that could affect my run times.

Thanks for all of the inputs guys!

sparky0068 · 03-26-2008, 01:20 PM

good number on the caps and your setting on your charger could easily be the runtime problem

Eritex Inc. · 03-26-2008, 04:45 PM

Jim, the problem is 2 fold.

First, the antenna is balled up. If you are using an AM tx/rx, the signal is so week that 15 feet is about all you can get before AM radio noise kicks in.

Second, the XRS esc has a low BEC. It is only 5.0 volts and 1 amp, a high torque servo can, at stall, pull enough amps to shut down the ESC. It can also cause it to glitch and twitch.

Cap, if you want to put them on, go for it. I haven't put caps on any of my crawlers, the motors don't spin fast enough to cause a noticeable amount of radio noise. At least I don't notice it.

Call me if you have anymore problems

thaclodking · 03-26-2008, 06:15 PM

I agree with Gerame. I had this same problem and I pinpointed it to the XRS' weak BEC supply. I ran a pigtail from the pack that only hit 5 of the 6 cells, giving a strong 6V straight to the receiver. This took care of all of my problems but it will cause some imbalance in the pack.

With that said I fully recommend Fruity Pebbles.

sniders1975 · 03-26-2008, 09:04 PM

Jay you are frikin funny!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!

kwkride · 03-27-2008, 06:55 AM

Thanks for the input guys! I'll have to try some things if I get some time tonight or tomorrow.

If the BEC is weak in the XRS, does that mean I should look at adding another one? (Maybe the Castle one?)

Thanks again,

JavelinSST390 · 03-27-2008, 10:32 AM

The castle BEC is a pretty cheap investment that could definitely solve your problem it sounds like.

sparky0068 · 03-27-2008, 01:18 PM

I run the Castle bec in both of my crawlers. It is the best single upgrade I have made.

kwkride · 03-28-2008, 06:38 AM

Just a quick update. The antenna is now sticking up in the air and 99% of my glitching is gone.

03-25-2008, 10:50 AM	#1
kwkride Rock Crawler Join Date: Feb 2008 Location: Nebraska Posts: 819	Electrical questions Hey Guys, I've got a couple of questions. First of all, I seem to have some glitching going on with my truck. It only happens when the truck is more than about 15 ft away from me and only when I am turning and backing up. The steering servo works fine, but the truck does not want to back up. I have to keep playing with the trigger to get it to move a little, or move closer to the truck. Could this be because I've got the antenna just tucked into the chassis instead of sticking up in the air? The other issue that I'm having is with run time. I purchased a small (2/3a 1400mah) 6 cell pack to cut down on weight. It works great, but I only get about 15 minutes of run time. Is this normal? Thanks, Jim Wheely King Stock HPI receiver 27mhz Novak XRS ESC Integy 65t motor

03-25-2008, 11:00 AM	#2
kwkride Rock Crawler Join Date: Feb 2008 Location: Nebraska Posts: 819	I just noticed this information about my servo. __________ This is the Futaba S3305 High Torque, Metal Gear Servo. per Futaba this servo is approved for use with NiCd batteries ONLY! This servo can produce high-current draw from your batteries. If using NiMH or LiPo batteries, make sure they are capable of delivering sufficient amps. __________ Could this be causing my issues? I didn't realize that the servo could require a specific type of battery. Jim

03-25-2008, 11:21 AM	#3
JavelinSST390 Rock Crawler Join Date: Jul 2007 Location: Rectalville Posts: 889	I don't know about your servo, if that would be the problem or not. Although I can't imagine why there would be a warning like that. NiMh and Lipo packs are capable of WAY MORE output than a standard NiCd pack. That all seems backwards? Are you running your antenna through the body still or did you hide it underneath? I hid mine underneath the body (actually just wadded it up and put it in the bag with the reciever before I zip-tied it shut.) And it works fine until the batt's on my Tx start getting low. Then it starts glitching pretty bad. I don't know if that helps or not. Gerame is the guy to talk to on this one. BTW, Those gears I ordered STILL haven't come in yet. I'm hoping they'll be here by thursday because I need to go to town anyway for my daughter's doctor's appointment.

03-25-2008, 12:16 PM	#4
sparky0068 Quarry Creeper Join Date: Jan 2008 Location: In the corn Posts: 331	Try running tyour ant. sticking out of your body if this fixes the glitching then you know your problem. On the battery problem you could try going back to the standard sub-c 6cell packs and gain run time at the cost of weight. My son runs his modded king with sub-c 6cell and he gets about an hour with a 3000mah ni-mh. My new truck that I am building will run sub-c's just for the run time. Are you still running the Jolt esc?

03-25-2008, 04:43 PM	#7
sniders1975 Quarry Creeper Join Date: Sep 2005 Location: Creeping in the Dark!!! Posts: 349	hey jim i run that same servo & have no problems with my batteries!!

03-26-2008, 12:53 AM	#9
sparky0068 Quarry Creeper Join Date: Jan 2008 Location: In the corn Posts: 331	caps are a must

03-26-2008, 01:20 PM	#11
sparky0068 Quarry Creeper Join Date: Jan 2008 Location: In the corn Posts: 331	good number on the caps and your setting on your charger could easily be the runtime problem

03-26-2008, 04:45 PM	#12
Eritex Inc. RCC Addict Join Date: Nov 2007 Location: in the woods Posts: 1,915	Jim, the problem is 2 fold. First, the antenna is balled up. If you are using an AM tx/rx, the signal is so week that 15 feet is about all you can get before AM radio noise kicks in. Second, the XRS esc has a low BEC. It is only 5.0 volts and 1 amp, a high torque servo can, at stall, pull enough amps to shut down the ESC. It can also cause it to glitch and twitch. Cap, if you want to put them on, go for it. I haven't put caps on any of my crawlers, the motors don't spin fast enough to cause a noticeable amount of radio noise. At least I don't notice it. Call me if you have anymore problems

03-26-2008, 06:15 PM	#13
thaclodking Rock Crawler Join Date: Sep 2004 Location: a place of settlement, activity, or residence. Posts: 842	I agree with Gerame. I had this same problem and I pinpointed it to the XRS' weak BEC supply. I ran a pigtail from the pack that only hit 5 of the 6 cells, giving a strong 6V straight to the receiver. This took care of all of my problems but it will cause some imbalance in the pack. With that said I fully recommend Fruity Pebbles.

03-26-2008, 09:04 PM	#14
sniders1975 Quarry Creeper Join Date: Sep 2005 Location: Creeping in the Dark!!! Posts: 349	Jay you are frikin funny!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!

03-27-2008, 06:55 AM	#15
kwkride Rock Crawler Join Date: Feb 2008 Location: Nebraska Posts: 819	Thanks for the input guys! I'll have to try some things if I get some time tonight or tomorrow. If the BEC is weak in the XRS, does that mean I should look at adding another one? (Maybe the Castle one?) Thanks again,

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03-27-2008, 10:32 AM	#16
JavelinSST390 Rock Crawler Join Date: Jul 2007 Location: Rectalville Posts: 889	The castle BEC is a pretty cheap investment that could definitely solve your problem it sounds like.

03-27-2008, 01:18 PM	#17
sparky0068 Quarry Creeper Join Date: Jan 2008 Location: In the corn Posts: 331	I run the Castle bec in both of my crawlers. It is the best single upgrade I have made.

03-28-2008, 06:38 AM	#18
kwkride Rock Crawler Join Date: Feb 2008 Location: Nebraska Posts: 819	Just a quick update. The antenna is now sticking up in the air and 99% of my glitching is gone.

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Thread: Electrical questions