ABC CRP problem: Turn left when accelerate

[ikinari]

I have two sets of ABC Crp unit, one on the dtm-x4, one on the mini-z, and I found this prob. on the both two.
That's happens when the run time is ending or when I use some high performance motor, so I guess the diminution of Amp or Volt causes it.
When using a tuned motor, it's serious. With full-charged battery, the car won't go straight as long as you throttle on. The car turns left. It's definitly a crp problem, not the matter of car setting or tyres. You just pick up the car, and throttle on in the air, the car steers left. Too bad, isn't it?
Anyone has the same problem?

[fastboy]

i would definately say its the voltage thats dropping too low under acceleration,are you using 6 cells or 4?
i assume the miniz is 4 cells,but you should be on 6 cells in the dtm.

you could pop a volt meter across the cells and see what the voltage is like under load when it makes the wheels turn left,the problem is with small cells,they struggle to deliver the amperage a quick motor needs and this may well be the weak link.

you could try hooking the car upto an external pack of larger mah and see if the car does the same,this way you will know its not the cells

good luck
dave

[ikinari]

Thank you very much, fastboy.
I'll try it later.
Now I use on DTM:
300mAh x 6cells

http://www1.bbiq.jp/ikinari/smallrc/dtm_x4.html
and on MINI-Z(not kyosyo, but Auldey):
2100mAh(AA) x 4 cells.

http://www1.bbiq.jp/ikinari/smallrc/...od.html#abccrp

One is 6 cell but small Amperage, the other is large, but only 4 cells. So I'll try 2100mAh x 6 external supply for testing the CRP...

[fastboy]

i have a dtm-x4 myself but i use mini-x electronics in it with a 7.4v 880mah li-poly and 180 motor and everything works great,hop e you get yours sorted ok.

dave

[ikinari]

fastboy, thanks for encouraging words!

I tried 6 cells of 2100mAh AAA on the ABC crp.
The test is just to throttle-on in the air.
The result varied for motors.

Result:
Plasma Dash : the same problem(steers left) appeared.
PN Racing S-03 motor: less appeared.
Core midified motor: hardly appeared.
Stock 130 motor: no problem.

So it seems to be a problem of the current draw.
The large curernt causes the servo trouble.
fastboy, I assume you use the "stock" 180 motor, right?
And that's why you dont face the problem, I guess.

But, I still wonder:
According to the specification note, the ABC crp should be able to take 60A continuous, 240A in peak.
But the Plasma Dash requires just 4.1A even ON LOAD. It's relatively small enough for the crp, isn't it? Why such a problem occurs?
In addition, the test above is done without any load. When the car runs on the ground, the current draw will be more, so the problem will appear more clearly...

[fastboy]

ok,have you tried a volt meter on the cells while accelerating?
you could also try a volt meter across the servo(red and black lead,be careffull not to short anything tho!! ) to see if the servo is getting the correct voltage under load.

it seems either way there not alot you can do about it,maybe stick some other electrics in it, as i say the mini x stuff works great for me and yes its a stock 180(hpi) and way too fast for a small indoors room,i use it a small playground and its so fast.

good luck
dave

[Cian]

Third post form the top , as you thought Ikinari , it is a CRP problem...

http://tinyrc.com/forums/showthread....&threadid=1307

[ikinari]

Cian, thanks for the info.
I think it's the same problem that gertman faced... I'll return the crp to the ABC.

[kylelucas]

ikinari -

Hello again.

I was wondering if you ever learned more about the ABC CRP problem from ABC directly, and what they might have said?

I have just built my first X4 and installed a 27Mhz ABC CRP with a stock 180, and found the same TURN LEFT issue.

I am just starting to search for solutions online, and believe this might be the only discussion about this problem (even though it's few months old now).

Did you ever discover a fix? Did ABC have any advice for solving this issue?

What motor do you use with the best results in your X4?

Any guidance would be appreciated.

I hope all is well.

Kindest Regards,
Kyle Lucas
kydawg1@yahoo.com

[ikinari]

Hi Kyle,
unfortunately, nothing updated on my side. I've not even return it to the ABC Hobby.

But I'll try Lithium Polymar soon. If the problem was caused by current draw, the batteries which can discharge more amperage may solve the problem.

[potentiality]

This may sound funny, but do those higher amp motors have the correct number of capicitors on them? 3 normally.

[kylelucas]

Ikinari-

I have some of my cars Li Ion powered and I did a quick test and found that the CRP has no issues at all under Li Ion Power. The steering servo has no actuation during acceleration / throttle ON.

I have not ran it on the floor yet (which will draw more current due to motor load), but the bench tests look very promising.

The current packs are too large for a maiden voyage, but I will try to get my hands on some AA sized Li Ion cells and make a pack to fit the X4. I will give another update then.

Best Regards,
Kyle

[potentiality]

Kyle, something that might help with the lower amp battery packs is a power capacitor. It gives the amperagea little bit of boost under hard throttle..

http://www.rczone.net/modules.php?na...rticle&sid=373

[kylelucas]

potentiality-

Thanks for the info. I will check it out.

The combo of Capacitors and Li Ion or Poly batteries should solve the problem.

It would be shame if these did not, since these cars and CRP units are so nice ..... and quite costly. The small design of this CRP is so perfect for the X4, it would be shame to have to scrap it and have to track down alternatives (ie:Spy, XXL or ES-01).

My best to all.

[MicroRCEngineering]

Why not just use 1/10th scale electronics, Kyle? I'll post a picture of my DTM SP this week and hopefully, it would be helpful.