Hey guys!

i just bought 2 RC buggy motors (Buggy Motor)

as i wanted to crate a vehicle using skid steeting (inspired by mahjqas metal grudge) i wired it up like the following:

the 8878 accu pack gives power to one IR Receiver

where i connected the buggy motors by using two 20cm extension wires. one motor goes to the red channel the other one to the blue channel.

the gear train is made like u can see below and i am using the faster rpm output (aoverall result is 453 rpms according to sariel's gear ratio calculator):

so now to my issue:

when driving around, sometimes the motors don't run smoothly, that means they are stalling on random, so the vehicle just does little "jumps" forward and can actually not drive fluently.

so the motors start running for a milisec and stop instantly, this makes driving impossible.

i checked if i made any mistake in wiring things up or the gear train has some problems, but everything works smoothly...

the IR Receiver isn't affected by strong light or anything else, and the accu pack was fully loaded before driving...

so i'm wondering if the battery pack can't deliver enough voltage or amperes to the motors that they won't run properly...

maybe the vehicle is too heavy, but except the power functions parts the chassis is only made of a few pieces... (it's definately lighter than 1 kilogramme)

so if u have any idea what might cause this problems please share your thoughts!

thx in advance

regards

chrizzle

I'm not sure but i think you should try to use two IR-Receivers instead of one. The Metal Grudge was also improved with two IR-Receivers because with one IR-Receiver you can't get the full potential from the two moters.

@ Chrizzle: Philo (Phillippe Hurbain) talks about the various 9V Lego Motors on this "LEGO® 9V Technic Motors Compared Characteristics" webpage. He wrote, "RC Race Buggy Motor 5292 is really powerful, but requires a power supply up to the task." The stalled current for the 5292 motor is 3.2 Amps. The 8878 "Power Functions Rechargeable Battery Box" can only deliver 7.4 V (not 9V), according to Sariel's

below. You may need to select another Battery Box that can deliver the high Amps needed for the 5292 Buggy motors.

Philo wrote that the 5292 Buggy motor "...seems to have a current limitation of about 4A, and a thermal shutdown providing on/off cycling like RCX motor driver." I remember that my son built a Lego Battlebot with whirling blades attached to a 5292 motor and a conventional 8881 Power Functions battery box. Whenever the blade got stuck on its opponent, the current limiter on the Power Functions RC Receiver kicked in, and the 5292 Buggy motor had to rest a few seconds to recover. I agree with P4trickvH that using TWO PF receivers will help.

Edited June 21, 201113 yr by DLuders

Chrizzle, you can't effectively power two buggy RC motors from one 8878 accu. It's simply too weak and it will keep shutting down due to the high energy consumption. That's why I keep using two 8878s, one for each RC motor, in MOCs like this:

Edited June 21, 201113 yr by Sariel

thank you guys for the fast replies!

then i will have to rebuild my construction and use two of the accu packs!

kind of waste that you have to use two of them in a single MOC^^

You can try to use a single RC module instead: http://www.bricklink.com/catalogItem.asp?P=6272c01

  On 6/21/2011 at 2:06 PM, Sariel said:

You can try to use a single RC module instead: http://www.bricklink.com/catalogItem.asp?P=6272c01

cool, i saw some of them on ebay recently but they are quite expensive

i hope i can get one soon!

I also had this problem but you have to take away the overload protection.

I have a problem with a V2 receiver.

If i use the throttle from forward to backward, to stop (or i crash), it has always a 1 second delay before it stops

And then i crash. so this is very annoing so does anyone knows a possible issue?

P.S I changed the batterys in the 'sender' and it odesnt makes a difference.

I know this is a old topic, but I recently bought a single buggy motor, and put it in a car frame together with a servo motor on a single 9v AA batery pack and using a v2 receiver. this setup doesn't work because the motor shuts down after some driving, to start up a bit later. l Then I wired my buggy motor to a switch, controlled by a m motor wich is connected the receiver instead the buggy motor. After some driving the batery box shut down. Is there an fix for this without buying a rc unit? because I am low on money.

If needed I have spare batery boxes so I can cheat a bit.

Sbrick instead of V2.

I believe LiPo or AAA battery pack is better than using AA pack.

Buwizz instead of everything above.