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Sabertooth 2X25
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Daniel
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Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast


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Sabertooth 2X25

People keep asking me about this speed controller since I have one and everyone in interested in getting one. I'll post the good bits and bad bits I've found so far.

Good bits:
- It's small
- It's easy to set up. The online dip switch thing is handy.
- The over current bit works
- The LiPo detection and low voltage cut out is good

Bad bits:
- At 24V with cordless drills and 75mm wheels the over current protection will cut the power when you slam the sticks. You need to slowly ramp the power which I know I'd forget to do during a fight.
- It needs a really good signal to work. I lost my antenna a few years ago and the IFI's I use have never had a problem. Once I put the top on the robot the speedo started to glich. It would either not go forward when I tell it to or even worse it would not stop. This is because I haven't read the instructions and set the failsafe. The radio problem seem to be a big problem since the IFI I had on the weapon always worked fine all day. After 4 years of never having a radio problem it certainly is a shock.

Post Sun May 04, 2008 7:02 pm 
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Fish_in_a_Barrel



Joined: 30 Sep 2006
Posts: 673
Location: Perth, Western Australia


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Yeh, Trav mentioned something to me about the full power seeming a bit low. Are you saying that it will cut the power to a low value instead of simply switching to a constant current mode?
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Post Sun May 04, 2008 7:13 pm 
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Daniel
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Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast


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You slam the sticks and nothing will happen. The robot might then jump slightly and then go. I'm guessing it simply cuts all power if the current is too high, it then jumps as the current drops or a time delay but then cuts out as it goes high again. The jumps create a bit of momentum which lowers the current draw until it moves off. All up this takes about a second which seems like a life time while your driving.

Post Sun May 04, 2008 7:30 pm 
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Philip
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Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


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It would be interesting to put a data logger into the robot to find the maximum current draw. It would be interesting to find out exactly how many amps will shut down the Sabertooth.
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Post Sun May 04, 2008 10:17 pm 
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bytraper



Joined: 31 Oct 2005
Posts: 195


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I've got a custom Sabretooth 2x25, Its got the higher current shutoff and higher ratings than a stock unit to combat the problem with the shutoff at overcurrent.
The 2x25 can be used for bots but wasn't specifically designed with that in mind.

Theres a new version coming out which will address the problems listed below called the battle version... Its more robust (see my build thread to see the differences) and handles higher amperage across the board.

Cheers!
Shane


Bad bits:
- At 24V with cordless drills and 75mm wheels the over current protection will cut the power when you slam the sticks. You need to slowly ramp the power which I know I'd forget to do during a fight.
- It needs a really good signal to work. I lost my antenna a few years ago and the IFI's I use have never had a problem. Once I put the top on the robot the speedo started to glich. It would either not go forward when I tell it to or even worse it would not stop. This is because I haven't read the instructions and set the failsafe. The radio problem seem to be a big problem since the IFI I had on the weapon always worked fine all day. After 4 years of never having a radio problem it certainly is a shock.

Post Tue May 13, 2008 12:37 pm 
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Collo



Joined: 06 Apr 2008
Posts: 130


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I have just bought one of these for my first attempt at a bot....but I can't get it to work. The motors and batteries are wired up and the R/C Hobby style reciever is connected to the other side, but when everyhtings turned on the motors dont spin. can someone please hlep me.

Thanks, Collo

Post Fri Sep 19, 2008 4:52 pm 
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andrew



Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W


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have a battery powering the receiver if not that then not sure.

there a touchy subject this controller, i purchased one and had no issues with it running two 100 watt scooter drive setups at 24 volts but other people have had nothing but issues with them.

people use the scorpion and i had nothing but issues with my first one of them also so i guess its luck of the draw really

add me on msn if u wanna chat and i can help u further
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Post Fri Sep 19, 2008 4:55 pm 
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Glen
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Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect


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what happens with the status LEDs?

what are you using to input signals? (radio control reciever or a pot)

make sure you have the

0v hooked up to ground from the reciever (black or brown)
5v hooked up to the power out of the reciever (red)
S1 hooked up to the signal out of one of the reciever channels (orange)
S2 hooked up to the signal out of one of the reciever channels (orange)

if your running it from an rc reciever AND set the dip switches so -

switch one DOWN and switch two UP

theres alot of crap to do on these things i never realised Confused i know andrew with puncturer went from this to the scorpion xl.. any other experiences?
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Post Fri Sep 19, 2008 5:21 pm 
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Collo



Joined: 06 Apr 2008
Posts: 130


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woow, you guys relpy quickly. Yeah all that has been done, battery pack for the reciever and 2 blue lights, the second flashes in bursts of 4. All the wires are in the right order: 2 Blacks (ground), 2 red (5 V) and 2 white (S1 & S2). I have tried with the wires other way around, and the battery pack not connected.

For now i have the XU1 battery for power and an RC batt for the reciever. Thinking of getting A123s when its all good.

Thanks, Collo

Post Fri Sep 19, 2008 5:34 pm 
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Andrew W



Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria


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I've never had one of these. Daniel K had one in his robot at Battleshed and had some real problems with it.

Post Fri Sep 19, 2008 6:06 pm 
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kkeerroo
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Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane


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After Daniel brought the controller home I found a battery connector was bent and mixing turned on on both the controller and the radio causing calibration issues.
But testing will continue.
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Post Fri Sep 19, 2008 7:08 pm 
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Daniel
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Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast


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In both fights where I used the Sabretooth on the weekend I had problems where the damn thing decided to reset the center position during the fight. This ment that in both cases the robot would constantly drive forward and when I put it in reverse the robot wouldn't move or move slowly. So in the fight against Bender, Hellcat wasn't stuck under the wall but was actually about 50 - 100mm away most of the time and just needed me to turn right rather then try to back out. Not that I was asked if it needed unsticking.

The second problem was that the controller completly died for no reason. I was testing it in the arena before the fourth round and I was driving it in a straight line when it suddenly lost power and refused to start again until I gave it to my brother on Tuesday. He thinks it was a loose connection inside the terminal block.

These two problems with the others I have already listed mean that I won't be using this controller anymore. I'll stick with my IFI's.

Post Fri Sep 19, 2008 8:33 pm 
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Glen
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Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect


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sad as it is to say the IFIs are THE best robot controller. there so hard to kill. controller isnt too great though Smile

what are the fets on a sabretooth as well? are they the H bridge chips like the scorpion or SOT23 fets?
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Post Fri Sep 19, 2008 8:39 pm 
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Daniel
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Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast


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As I said somehwere else before, everything on the back of the board is covered with a heatsink. You can't see anything underneither and if anything on that side blows it would be way too much effort to find and fix.

Post Fri Sep 19, 2008 8:41 pm 
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Collo



Joined: 06 Apr 2008
Posts: 130


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So they really arent any good? Sad
Anybody had some GOOD experience with these, because im 16 and my brother is 13 so if we can use what we have for now...

What are these IFI's? heard of the IBC.

Thanks, Collo

Post Fri Sep 19, 2008 9:36 pm 
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