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Hey All,
I wanted to demonstrate the current handle capabilities of the EZ-B and at the same time doing a small test. Here's a quick video I made of Six with 18 servos, I know a few of you asked a long time ago if Six could run with 18 servos, the answer is Yes!
I also wanted to demonstrate the large in rush current demand that Heavy Duty servos can have and how it might effect your power supply or battery pack so I made another quick video :
this is great info, save to pocket...
j
Good point Doc... Most of the cheap ones are not fused on the 10amp setting, by the way so be careful...
I just bought a Uni-T UT61E and it's awesome....
Thanks for the videos Jeremie.
It really does concern me that very few will do things the right way. What use is a robot that's had thousands of man hours spent on building it if it doesn't work or if the wiring melts inside?
I have expressed concerns about the power (is the battery capable? is the wiring big enough? etc.) in the past on some projects but it's generally been brushed aside. I don't like to say I told you so or be Mr. Know-It-All but, well I did tell a few of you.
@Ant, you need to set the meter to DC amps (DCA) and connect it inline between the battery and the connector that currently attaches to the positive on the battery.
I've said it before, I'll say it again, design and calculations for everything is more important than anything else. If you want your robot to work you need to carefully think about what will power it, what will be powered but most important (and something that's not been touched on) what size the wiring needs to be.
No offence is meant to anyone by this and I'd much rather be saying "Wow, that turned out awesome and works well" than saying "you need to change your power supply and replace the cable that was smoking".
Couple of things.
Dave Schulpius. Wow, awesome analogy using the water pipe to describe volts, amps, and resistance. I am going to use that in the future...
A clamp on ammeter can measure the amperage without the power going through the multi-meter so it is possible to get a less expensive one that wouldn't be able to handle the current itself to measure very high amp circuits. See http://en.wikipedia.org/wiki/Current_clamp
I have a pretty cheap radio-shack meter, but it has a clamp on attachment and can measure hundreds of amps (not that we should need to measure that high on a robot, but still....).
Alan
Isn't the clamp on amp reader only used for AC amps ?
You can get ammeters which can measure ac or dc. Powerstream make some, the PST-CM01 for example.
My cheapo radio shack one does AC or DC, although to be honest, I have only measured very high amp DC circuits (my Toyota Prius drive motor - 300 amps max under load).
Alan
@Anthony, sorry it took me a little bit to get back to you
For the 18 servo test I was using our 7.4VDC 1300mAh LiPo battery and was powering all the servos through the v4. Something to note: the servos cannot effect the regulated supply of the EZ-Bv4 and cause the EZ-B to reset unless the entire power supply browns out.
Something that I forgot to mention was that inside the robot we have a wiring harness that has low gauge wire and a deans connector that are designed for high current delivery from the battery to the EZ-Bv4 and then to the Servos. It looks like this:
The micro deans adapter board is the same one as in the Power base (minus the 2.1mm barrel jack) and can be modified to use for your robot's wiring harness if needed.