RCCrawler Forums

007KRAWLER · 11-02-2006, 09:40 PM

Ok so here is the problem:
I have just fininshed putting togeter my first crawler. Chassis is a Rock bull 2 w/55 motors. rear steer, all alloy everything, Rebel 2 speed control Tq3 controller modded for variable rear steer. First set of servos were Hitec hs645 's front and rear. Truck worked ok for first battery. But by the end of the first battery the rear servo had already given up on life (Motor noise, Slipping etc.) I got pissed off because this was it's first ever run and I realy was not playing on very large rocks or getting it stuck in rocks where the servo's were getting over worked.

So I did some research on rc4wd.com the place where I purchased the truck kit.
I ordered some Hitech hsr-9559's robot servo's for the front and rear and charged the battery pack using fussy logic. (I figured that I would see what that would do!) After charge and cool down of the battery I took the vehicle out for it's second ever run.

Here's what's happening:

If I try and use the front and rear steer and move either forward or backwards the vehicle sometimes (More often than not) freezes and won't move. Sometimes the steering will not work either front or rear. (Almost like it is overworking the battery or Speed control,)

I went to a local hobby shop and they said that it could be the servo's drawing to much power/ speed controler being overloaded. They suggested trying to run a hump pack battery pack for the servo's
So I purchase the hump pack today. I still need to charge the Hump b4 I can test to see if this is the answer.

Sorry for the long post but I figured that someone else must be able to help identify what the problem is.

Again- running 2 x hitec hsr 9559tg Servo's/ tikin rebel 2 speed control/2 x 55L motors/ 1 Battery pack 3000ma. and a modded tq3 with varible rear steer.

Please help

Espeefan · 11-02-2006, 11:03 PM

My bet is the Rebel 2's BEC is not capable enough to handle two digital servos like 9559s, for one reason or another. The BEC is supposed to be rated at 5 Amps, which should be plenty, but it's a cheaper speedo, so who knows what to expect. My Super Rooster happily runs two Hitec HS-5945MG digital servos without any issues and it's only supposed to be a 3 Amp BEC.

Try a reciever pack, since you already have it. That should tell you real quick what's going on. Otherwise, the cost of the Rebel 2, now a reciever pack, a few bucks more and you could have gotten a real speed controller. No hard feelings, but an speed controller is not an item to be cheap with. It's an investment. It sounds like you didn't spare much expense on the rest of the build....

007KRAWLER · 11-02-2006, 11:21 PM

You are correct. I spared no expense as per usual it seems. (My nitro car is a unlimited engineering 7076 alloy and titanium car. Kinda Looks like a T max only 1000 times stronger)

I tried it again after charging the battery (The standard Battery) and same sh1t happened. Very frustrating. So I tried it with the Red wire pulled out of the ESC (Per the recomendations of the folks at Gyro Hobbies) and installed the hump pack (straight out of the bag without a charge) and all seemed to work well.

I am charging the hump pack now and will try it again tomorrow or saturday.

I think this may have solved the problem.

The frustrations lie with the initial purchase. I asked for all the best possible stuff from the get go, and was more than willing to pay for it. (even asked if I should run all alloy clod axles instead of the plastic.)

I don't mind spending money so long as it is money well spent. Not Good Money after Bad, If you konw what I mean.

Like I stated It seems to be working with the hump pack. (initial 1 min test)
I still would like any other input from anyone who is in the know
Thanks

ThinkTank · 11-02-2006, 11:30 PM

you can't run off a hump pack forever
since you just said you don't mind spending money for quality stuff, i would suggest that you invest in a better esc

run2jeepn · 11-03-2006, 02:48 AM

A 30 dollar Moped with the old servo's would have worked fine. Try this ESC....
Looking for a good, waterproof, no pause reverse ESC?

JohnRobHolmes · 11-03-2006, 05:22 AM

The robot servos will draw more than 5 amps each at stall. There is no ESC that will keep up with them. An easy way around your hump pack is a servo regulator AKA voltage regulator. The cheapest solution is the MPI regulator. It takes the place of your hump pack.
http://www.google.com/search?hl=en&q...=Google+Search

007KRAWLER · 11-03-2006, 10:46 AM

Quote:

Originally Posted by johnrobholmes

The robot servos will draw more than 5 amps each at stall. There is no ESC that will keep up with them. An easy way around your hump pack is a servo regulator AKA voltage regulator. The cheapest solution is the MPI regulator. It takes the place of your hump pack.
http://www.google.com/search?hl=en&q...=Google+Search

Is there really no ESC that can keep up with what I Need?
If this is the case, you stated that the CHEAPEST solution is the MPI regulator is this the very best for the task? If not, what is the best volltage regulator for this Job?

Also, someone else posted that I can't run a Hump pack forever.
Why not?
What is the downside?

Thanks again,thanks for the educated input.

JohnRobHolmes · 11-03-2006, 10:56 AM

Hump packs need charging just like normal packs. It is a hassle to keep em charged, and they can discharge before the main pack in a crawler.

The MPI is cheapest because it is a linear regulator. Running 6 cells you will get around 8 -10 amps of power available at 6 volts. The higher voltage the main pack, the less power the regulator can give the servos. You could go with a switching (digital) regulator but it will cost $40, only have 3 or 3.5 amps of power, but have a very large working voltage range (up to 40 volts for most) and be very tiny.

Except in smaller crawlers, I normally choose the MPI over anything else.

What servo do you have again? the 5995 or the 5955? The 5995's can be run directly off your main pack as long as you watch the heat.

11-02-2006, 09:40 PM	#1
007KRAWLER Newbie Join Date: Oct 2006 Location: so cal Posts: 4	HELP!!! I need you help with electronics Ok so here is the problem: I have just fininshed putting togeter my first crawler. Chassis is a Rock bull 2 w/55 motors. rear steer, all alloy everything, Rebel 2 speed control Tq3 controller modded for variable rear steer. First set of servos were Hitec hs645 's front and rear. Truck worked ok for first battery. But by the end of the first battery the rear servo had already given up on life (Motor noise, Slipping etc.) I got pissed off because this was it's first ever run and I realy was not playing on very large rocks or getting it stuck in rocks where the servo's were getting over worked. So I did some research on rc4wd.com the place where I purchased the truck kit. I ordered some Hitech hsr-9559's robot servo's for the front and rear and charged the battery pack using fussy logic. (I figured that I would see what that would do!) After charge and cool down of the battery I took the vehicle out for it's second ever run. Here's what's happening: If I try and use the front and rear steer and move either forward or backwards the vehicle sometimes (More often than not) freezes and won't move. Sometimes the steering will not work either front or rear. (Almost like it is overworking the battery or Speed control,) I went to a local hobby shop and they said that it could be the servo's drawing to much power/ speed controler being overloaded. They suggested trying to run a hump pack battery pack for the servo's So I purchase the hump pack today. I still need to charge the Hump b4 I can test to see if this is the answer. Sorry for the long post but I figured that someone else must be able to help identify what the problem is. Again- running 2 x hitec hsr 9559tg Servo's/ tikin rebel 2 speed control/2 x 55L motors/ 1 Battery pack 3000ma. and a modded tq3 with varible rear steer. Please help

11-02-2006, 11:03 PM	#2
Espeefan Rock Crawler Join Date: Jun 2006 Location: Wisconsin Posts: 570	My bet is the Rebel 2's BEC is not capable enough to handle two digital servos like 9559s, for one reason or another. The BEC is supposed to be rated at 5 Amps, which should be plenty, but it's a cheaper speedo, so who knows what to expect. My Super Rooster happily runs two Hitec HS-5945MG digital servos without any issues and it's only supposed to be a 3 Amp BEC. Try a reciever pack, since you already have it. That should tell you real quick what's going on. Otherwise, the cost of the Rebel 2, now a reciever pack, a few bucks more and you could have gotten a real speed controller. No hard feelings, but an speed controller is not an item to be cheap with. It's an investment. It sounds like you didn't spare much expense on the rest of the build....

11-02-2006, 11:21 PM	#3
007KRAWLER Newbie Join Date: Oct 2006 Location: so cal Posts: 4	You are correct. I spared no expense as per usual it seems. (My nitro car is a unlimited engineering 7076 alloy and titanium car. Kinda Looks like a T max only 1000 times stronger) I tried it again after charging the battery (The standard Battery) and same sh1t happened. Very frustrating. So I tried it with the Red wire pulled out of the ESC (Per the recomendations of the folks at Gyro Hobbies) and installed the hump pack (straight out of the bag without a charge) and all seemed to work well. I am charging the hump pack now and will try it again tomorrow or saturday. I think this may have solved the problem. The frustrations lie with the initial purchase. I asked for all the best possible stuff from the get go, and was more than willing to pay for it. (even asked if I should run all alloy clod axles instead of the plastic.) I don't mind spending money so long as it is money well spent. Not Good Money after Bad, If you konw what I mean. Like I stated It seems to be working with the hump pack. (initial 1 min test) I still would like any other input from anyone who is in the know Thanks

11-02-2006, 11:30 PM	#4
ThinkTank Release your anger.. Join Date: Oct 2006 Location: North American Union Posts: 1,063	you can't run off a hump pack forever since you just said you don't mind spending money for quality stuff, i would suggest that you invest in a better esc

11-03-2006, 02:48 AM	#5
run2jeepn I wanna be Dave Join Date: Sep 2005 Location: USA Posts: 11,196	A 30 dollar Moped with the old servo's would have worked fine. Try this ESC.... Looking for a good, waterproof, no pause reverse ESC?

11-03-2006, 05:22 AM	#6
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	The robot servos will draw more than 5 amps each at stall. There is no ESC that will keep up with them. An easy way around your hump pack is a servo regulator AKA voltage regulator. The cheapest solution is the MPI regulator. It takes the place of your hump pack. http://www.google.com/search?hl=en&q...=Google+Search

11-03-2006, 10:56 AM	#8
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	Hump packs need charging just like normal packs. It is a hassle to keep em charged, and they can discharge before the main pack in a crawler. The MPI is cheapest because it is a linear regulator. Running 6 cells you will get around 8 -10 amps of power available at 6 volts. The higher voltage the main pack, the less power the regulator can give the servos. You could go with a switching (digital) regulator but it will cost $40, only have 3 or 3.5 amps of power, but have a very large working voltage range (up to 40 volts for most) and be very tiny. Except in smaller crawlers, I normally choose the MPI over anything else. What servo do you have again? the 5995 or the 5955? The 5995's can be run directly off your main pack as long as you watch the heat.

Sponsored Links

RCCrawler Forums

Thread: HELP!!! I need you help with electronics