Sabretooth speed controller

Remote-Controlled Dave · Thu Oct 02, 2008 12:08 pm

Hi y'all.
My latest bot is running using one of these Sabretooth Dual 5A motor controllers, which seem to be just a scaled-down version of the one in my featherweight.
Robot is now working but its far from its full capacity. It goes forwards and reverses at about half the speed its capable of, and when it turns its a mere fraction of that speed.
Now I'm currently only running it off a 4.8v Nicad pack cos one of my Lipos blew up and I havent bought a replacement yet. Will the swap over to a 7.4v Lipo pack solve my problems, or is it something else?
Ta. Dave.

peterwaller · Post by **peterwaller** » Thu Oct 02, 2008 1:21 pm

DC motors give a constant speed per volt. A two cell lipo is 8.4 on full charge so 4.8/8.4 give 0.57 so you will only get 57% of the speed at 4.8v that you will get at 8.4v.

Remote-Controlled Dave · Thu Oct 02, 2008 4:57 pm

Thats what I thought yeah. OK, cheers Peter.

Remote-Controlled Dave · Fri Oct 10, 2008 7:47 pm

OK, I've put the lipo in and its much better than it was, however it still turns a lot slower than it goes forwards and backwards....any tips?

Simon Windisch · Post by **Simon Windisch** » Fri Oct 10, 2008 9:32 pm

Just an idea Dave, but stick a voltmeter across the motor terminals and see if you get a different voltage forwards or backwards.

Simon

Remote-Controlled Dave · Fri Oct 10, 2008 9:57 pm

I would Simon, but this is me we're talking about...I dont have a voltmeter, and to get to the terminals now would pretty much require a rebuild...lol.

Simon Windisch · Post by **Simon Windisch** » Sat Oct 11, 2008 9:26 am

Do you have a picture of the robot Dave?

Simon

Remote-Controlled Dave · Sat Oct 11, 2008 10:30 am

Well, I just went to make a video of said robot so you could see the problem, and, well, there no longer is one for some reason. Lol, seems the solution was to, er, leave it overnight...or something.
Simon, why did you want a picture? Trying to spy on my latest ants of awesome rubbishness?

Flippt · Post by **Flippt** » Sat Oct 11, 2008 6:01 pm

I would have suspect that some settings on the Sabertooth were crashing with the ones on your transmitter. Me and my buddy had a such a problem with the Sabertooth 10x2. Our Mixers on the speedcontroller and transmitter didn't like eachother.

Remote-Controlled Dave · Sat Oct 11, 2008 7:48 pm

I did consider that Joacim, and you might be right, cos I swtiched the mixer off on the transmitter and it worked better.