Pre-Order Focbox Unity $249 | R-SPEC Drive Kit $579USD

FOCBOX input voltages alternating/fluctuating

focbox

#1

Hi there,
i realized today that one of my two focboxes has a really bad input voltage accuracy.
Here is a quick graph showing a comparison to the other Focbox, not quite accurate since the values are just the result of entering “volt” in the Terminal followed by arrow down plus enter :slight_smile: and it took place one at a time.

What is the consequence of this? Is this a symptome of a common error, maybe loose caps? Can I still drive with it or does it need repair?

Michael


#2

Maybe to tag @JohnnyMeduse he for sure can tell you what could cause it.


#3

Check power leads for bad solders/loose contact. Thats my initial thought.
Or the Caps.


#4

it looks a bit like a bad solder joint, let’s see if resoldering will work…

edit: resoldering the cap connections didnt help, now, lets see how the xt60 look underneath the shrinktube :slight_smile:


#5

hmm, resoldered the xt60, still not better :frowning:


#6

Are those reading from an app or the bldc tool (or vesc tool)?


#7

Both. when reading from vesc tool and by metr pro.


#8

That is kinda weird… Maybe you could try to add some solder to the big cap.

Also, I see some solder ball near the DRV. i could be a good idea to clean the pcb a little


#9

You could always swap the two xt connectors and see if the problem jumps to the #2 FocBox.


#10

hmm, nothing is working. Since I’ll send some other Focboxes to @Martinsp I just send this one along, maybe he’ll find something :frowning:


#11

If it rides without problems (errors, cogging etc) it should not be a very big issue, what were you powering it with? Battery or some other power supply? You could also try to spread the pins on the XT connector to put a bit more preload there but assuming it rides without some issues that should not be the case.
Was the measuring done under load?


#12

Not for the above diagram but the voltage indicator in metr jumped rapidly when I drove. It worked but I had a bad feeling about it so I didn’t drive a lot. I replaced the focbox with a fsesc 4.12, now it’s working. The fsesc has no fluctuations at all, the left focbox has little but no huge spikes like in the diagram and it doesn’t affect metr.