RE: I plunged and ordered a $100 1:10 Brushless system  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       

All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> RC Electric Off-Road Trucks, Buggies, Truggies and more >> RE: I plunged and ordered a $100 1:10 Brushless system
Page: <<   < prev  1 2 3 [4] 5 6 7 8 9   next >   >>  

Login
Message << Older Topic   Newer Topic >>
RE: I plunged and ordered a $100 1:10 Brushless system - 1/18/2008 1:01:54 AM   
Access


 

Posts: 2490
Joined: 3/8/2005
From: , CA, USA
Status: online 		Don't forget about vector drives or PFM or burst-mode, not every ESC in existance uses PWM (all the time). Burst-mode and PFM (relative to PWM) improve efficiency at low throttle / light loading. A vector drive features 'smooth' transitions from one pole to the next which improves super-low-RPM smoothness at the cost of efficiency and complexity.

(in reply to studysession)
       Post #: 76

RE: I plunged and ordered a $100 1:10 Brushless system - 1/18/2008 3:43:25 AM   
snellemin



Posts: 727
Joined: 3/22/2007
From: Tomball, TX, USA
Status: offline 		Here are the pics. With the added caps I was able to run 6s1p A123 on the motor it came with. Put on heatshrink, fan and it's good to go.





< Message edited by snellemin -- 1/18/2008 4:39:48 AM >

_____________________________

check out www.Hamdrl.org
Snelle-RC, A123 Racer

(in reply to Access)
       Post #: 77

RE: I plunged and ordered a $100 1:10 Brushless system - 1/19/2008 8:46:52 AM   
Matthew007


 

Posts: 221
Joined: 11/22/2007
From: Brooklyn, NY, USA
Status: offline 		Nice. How fast are you going?
I'm going at least 30mph with 7.2V, the motor it came with and stock tires.
Are you happy with your purchase? I know I am.

Here's me ballooning 4 dirt work tires and then having it vibrate off heheh

video link

< Message edited by Matthew007 -- 1/19/2008 9:09:12 AM >

(in reply to snellemin)
       Post #: 78

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 3:36:16 AM   
Matthew007


 

Posts: 221
Joined: 11/22/2007
From: Brooklyn, NY, USA
Status: offline 		I had to order the pressure plates on both the ball diff cause it stripped. Such a stupid design to use such small teeth to connect the wheel axle hub to the differential. But then again they can now make more money off of me, and that's the whole point of rc hobby for them.

Anywho, I also ordered 8.4v flat 7 cell 3800 mah from all-battery, I'm sure it'll fit I just have to secure it. Hopefully it goes noticeably faster

Any news for you snellemin? Usually when people don't reply for a while it's because A) They're busy having too much fun or B) There's no news since it is out of commission.

(in reply to Matthew007)
       Post #: 79

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 3:18:52 PM   
snellemin



Posts: 727
Joined: 3/22/2007
From: Tomball, TX, USA
Status: offline 		I've been experimenting with different fets on mine. No luck so far.

_____________________________

check out www.Hamdrl.org
Snelle-RC, A123 Racer

(in reply to Matthew007)
       Post #: 80

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 4:13:09 PM   
jesusthepirate


 

Posts: 2
Joined: 1/25/2008
From: , VA, USA
Status: offline 		snellemin - did the stock FETs let the smoke out on your 6s1p A123 pack, or give you some other sort of trouble? does anybody have the actual markings on the front of the stock FET's? wondering how many amps it can handle on 3s2p. (or 6s2p, if that doesn't fry it).

When I saw this thread it caught my attention: I figured if this ESC is good for a reasonable number of amps (and the voltage), then a 6s2p A123 pack + this ESC + maybe a 540L or 540XL... that's a pretty cheap BL setup for a maxx or savage sized truck.

BTW I emailed modellfun and got this pricing: The ESC is 42USD and the PG card is 10USD. Freight is 17.5USD by the EMS.

Matthew007 - how is cogging now for you? is it relatively smooth now or?

thanks for the great reporting on this stuff guys.

(in reply to snellemin)
       Post #: 81

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 4:25:54 PM   
snellemin



Posts: 727
Joined: 3/22/2007
From: Tomball, TX, USA
Status: offline 		The fets on one phase blew up on me when I tried it with 6s1p A123 and a 8s Feigao. I believe it's my overgearing that caused it. The fet model is IRL3803. I also believe that it will be fine with 6s A123 if you keep the amp draw down. Better ESC have double to triple the amount of fets.

_____________________________

check out www.Hamdrl.org
Snelle-RC, A123 Racer

(in reply to jesusthepirate)
       Post #: 82

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 6:01:45 PM   
rschoi_75



Posts: 1816
Joined: 2/1/2006
From: Los Angeles, CA, USA
Status: offline 		I received mine in last weekend as well. So far I've had good luck running it in my jammin x1 buggy on 5s lipos. I haven't got a chance to get an extended run in since its raining cats and dogs here, but it held up for almost 10 minutes straight with no issues on 18.5v. I'm running a Feigao 8xl w/ 16/48 gearing, and the lipo is a hyperion 5s 4800mah 20C. I haven't tried 6s since reading about snellemin's experience, and I don't think I'll push it that high.

Comparing this to my MM that used to be in here, I'd have to say that the esc does lag a little more at the start. Its not cogging, but a slight lag in the response. Start up is pretty smooth, but there is no low speed control. No going 1mph with this esc.... I tried a few times, and its either a dead stop or it will jump to 2-3mph (hard to tell). Not bad for a bashing esc, but I'm sure it would be annoying for someone trying to inch up to a starting line. To me its a non-issue, since I will never race with this esc. Programming was very easy with the card. Getting the controller to arm took a while, but that's just because I'm stubborn and don't like reading the directions .

I really hope I get to run it more this weekend. I can't give it a thumbs up or down yet since 10 minutes is hardly a full test. We'll see what happens over the next week or so. In the mean time, here's some pics of the esc and the rig its installed in right now.

Attachments
Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize


_____________________________

Of course I''ll have coffee... I always have coffee when I''m watching radar. Everyone knows that!

(in reply to snellemin)
       Post #: 83

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 7:26:14 PM   
jesusthepirate


 

Posts: 2
Joined: 1/25/2008
From: , VA, USA
Status: offline 		snellemin - I don't know anything about actually implementing circuits that use FET's, are you up on that or just playing around because it's already toast? I get the impression that the switching time or whatever is the central factor in whether or not any given FET will work properly with an ESC "brain," apparently due to these times being set up as part of the firmware. That's just my impression. Maybe if you got frustrated and just wanted a working ESC out of the bargain, you could cannibalize the FETs from the other 2 phases, and turn it into a 6-FET circuit (2 per phase) for half the AMP handling? or if you've still got maybe 1 good FET in that phase you could make it a 9-FET circuit... I don't know whether that would work, but it seems like it would. feel free to make a witty response if necessary.

rschoi_75 - that's good stuff which people need to know, ease of programming, startup power (can't creep around at all), etc. it's encouraging that you were able to whip around with it on 5s LiPo for 10min at least, looking forward to how you make out with it on longer runs once the rain lets up. as a new member I want to keep my head low, but -just- to make sure you noticed: snellemin's 6s pack is A123 (LiFe), which has a lower nominal voltage, so it's actually only 1v or 2v higher than your hyperion LiPo... whether or not that ~18-20v blows the ESC without overgearing for speed runs remains to be seen though.

(in reply to snellemin)
       Post #: 84

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 8:59:05 PM   
snellemin



Posts: 727
Joined: 3/22/2007
From: Tomball, TX, USA
Status: offline 		I'm will be buying another ESC soon to play with. The one I have is to experiment with. I like the idea of using 2 fets per phase. But then I have to be really gentle with it.

_____________________________

check out www.Hamdrl.org
Snelle-RC, A123 Racer

(in reply to jesusthepirate)
       Post #: 85

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 9:03:13 PM   
rschoi_75



Posts: 1816
Joined: 2/1/2006
From: Los Angeles, CA, USA
Status: offline 		yeah I saw that. He was running 19.8v in his. not too much higher than mine right now.

_____________________________

Of course I''ll have coffee... I always have coffee when I''m watching radar. Everyone knows that!

(in reply to jesusthepirate)
       Post #: 86

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 9:15:50 PM   
Access


 

Posts: 2490
Joined: 3/8/2005
From: , CA, USA
Status: online
quote:

ORIGINAL: snellemin
The fets on one phase blew up on me when I tried it with 6s1p A123 and a 8s Feigao. I believe it's my overgearing that caused it. The fet model is IRL3803. I also believe that it will be fine with 6s A123 if you keep the amp draw down. Better ESC have double to triple the amount of fets.

!!!
http://www.irf.com/product-info/datasheets/data/irl3803pbf.pdf
16V with those FETs. No more. 6s A123 and you are really pushing it. Vgs = 16V is too low unless they are using a specialized driver IC which I doubt they are. If the driver is pulling straight to ground to turn it off, it is going to blow very quickly on both the high side and the low side. Also Rds(on) of 6m-ohm is really high. You can get better MOSFETs at less cost even here in the US.

Look at something like this one.
http://www.fairchildsemi.com/ds/FD/FDP8860.pdf
Vgs = 20V, Vds = 30V and Rds(on) is 2.5-ohm.

Remember that MOSFETs are highly static-sensitive so take proper anti-static precautions, ground wrist strap and an anti-static mat over the work area at a minimum.

(in reply to snellemin)
       Post #: 87

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 9:31:17 PM   
snellemin



Posts: 727
Joined: 3/22/2007
From: Tomball, TX, USA
Status: offline 		Thanks Access. I'll see if I can get me some of those fets. Time to ask for more favors.

_____________________________

check out www.Hamdrl.org
Snelle-RC, A123 Racer

(in reply to Access)
       Post #: 88

RE: I plunged and ordered a $100 1:10 Brushless system - 1/25/2008 9:51:24 PM