SD540 Motor Controller

[Andrew Schreiber]

Originally Posted by notmattlythgoe

Don't think I've seen a robot get through a match without dipping that low in their battery voltage.

Pretty sure I've seen that on a non aggressively geared kitbot that only weighed 80 pounds... Unless the 9.5V limit only kicks in after a period of time in which case I'd like to see that in the documentation (and still complain because my use case for low cost controllers involves lower voltages anyway)

[geezloueez]

Originally Posted by notmattlythgoe

Don't think I've seen a robot get through a match without dipping that low in their battery voltage.

I am a first year mentor for a rookie team. May seem like a dumb question, but I have not been involved first hand in a match yet. What is causing the batteries to drop so low? Are you using old batteries?

[asid61]

Originally Posted by pnitin

If you are letting down your battery 9.5 V your are basically killing your battery( actually 10.8V that is 1.8V per cell).
Lead-Acid battery will quickly built lead sulfide layers on plates ( no matter what is battery technology and what manufacturer claims)
you are basically screwing up battery and now it will have much high internal resistance so the you will start seeing voltage drop when you try to take out good amount of current.

Hence why batteries in FRC have such a low lifetime... Interesting tidbit.
We don't use batteries from 2011 or earlier. And we're probably going to start phasing out the 2012 batteries too. They start being unable to hold a significant charge.

[Knufire]

Originally Posted by asid61

Hence why batteries in FRC have such a low lifetime... Interesting tidbit.
We don't use batteries from 2011 or earlier. And we're probably going to start phasing out the 2012 batteries too. They start being unable to hold a significant charge.

We only use batteries in competition for a single year. After that they'll be used for practice for 2-4 years and then recycled.

[Chris is me]

Originally Posted by pnitin

If you are letting down your battery 9.5 V your are basically killing your battery( actually 10.8V that is 1.8V per cell).
Lead-Acid battery will quickly built lead sulfide layers on plates ( no matter what is battery technology and what manufacturer claims)
you are basically screwing up battery and now it will have much high internal resistance so the you will start seeing voltage drop when you try to take out good amount of current.

Momentary drops to 9.5vs are not at all uncommon in FRC matches, depending on the number of motors on the machine, weight, traction, etc. It might not be great for batteries but I'd rather be able to drive for the rest of the match and potentially shorten a battery's life than not be able to drive to save a couple of bucks later on. Basically, I don't want the products I use to try and protect me from myself.

[pnitin]

Originally Posted by Chris is me

Momentary drops to 9.5vs are not at all uncommon in FRC matches, depending on the number of motors on the machine, weight, traction, etc. It might not be great for batteries but I'd rather be able to drive for the rest of the match and potentially shorten a battery's life than not be able to drive to save a couple of bucks later on. Basically, I don't want the products I use to try and protect me from myself.

Actually what I am trying to say here is if you treat your battery well, it will serves you faithfully, if you abuse it, it will not serve you well. Momentary drops are called spikes and most of the filter will take care of it ( you will not see brown out for spikes) I think problem is when you want to start with 9V battery to begin with, you have problem.

That way CTRE chart is incorrect since no one ( sane person) will be turning on robot with 9V battery level in competition.
what you really want to see is how well they handles those spikes.
.

[thatprogrammer]

Now that this season is over, I would like to ask if any teams used this controller this year and what they thought of it.

[geezloueez]

I mentor team #6194. We used the SD540B and had great results. The controllers gave out great power. We qualified for the Cheseapeake District Championship in Maryland as Rookie Team. We will use this controller again next season.

[udpatil]

Team 540 also used the controllers this year and they were very successful for us. We had 7 controllers on our robot for the drivetrain, flywheel shooter, pickup mechanism, and manipulator arm and each used the SD540B motor controller. We used three single controllers and two sets of double controllers (the 2 controller bank). Overall, they were good and we were able to go all the was to St Louis with our successes and made one of our best robots in team history!

[FarmerJohn]

Can someone outside of Virginia comment on their experiences with these motor controllers? Just looking to eliminate any potential regional bias.

[Joe Ross]

Originally Posted by FarmerJohn

Can someone outside of Virginia comment on their experiences with these motor controllers? Just looking to eliminate any potential regional bias.

Per http://www.firstinspires.org/robotic...-the-numbers-2 only 7 teams uses SDS540s. Of those 3 used it as their only motor controller, 2 used it as their primary motor controller, and 2 used it for 50% or less of their motor controllers.

[mindsensors.com]

Originally Posted by AllenGregoryIV

Not to be a buzz kill but did you guys just copy the data complied by REV for the Spark? Even the disclaimer is the same.

Credit has now been given below the chart.

[BBray_T1296]

For the 7 people who say they "do not like this product" could I ask why? Seems like a perfectly competitive option. What is there to not like?

[wilsonmw04]

Originally Posted by BBray_T1296

For the 7 people who say they "do not like this product" could I ask why? Seems like a perfectly competitive option. What is there to not like?

It could be that it's new. It might also be kids who have no idea what they are talking about. I really think it's the fact that some folks just like to be snarky when a poll is anonymous.

[wmarshall11]

Originally Posted by BBray_T1296

For the 7 people who say they "do not like this product" could I ask why? Seems like a perfectly competitive option. What is there to not like?

Originally Posted by wilsonmw04

It could be that it's new. It might also be kids who have no idea what they are talking about. I really think it's the fact that some folks just like to be snarky when a poll is anonymous.

There's also no "I'm ambivalent about these features" option. "I do not like it, Sam-I-Am" becomes the default option, since the others are super positive about the product.

From my chair, none of the features of the SD540 stand above my primary criteria for selection of a speed-controller, which is "Reliable, as verified by real FRC teams using real hardware on a real robot".

Not to imply that the product isn't reliable, just that being burned to the tune of a set of speed controllers during build/competition season is enough disincentive to keep me preferring more tried-and-true offerings.