Power Cutoff when accelerating

How-Tos & Esk8 mechanics Esk8 Mechanics
#44

I lowered this long ago to 35v cutoff start and 33v cutoff end. Its rare that I ever let the total volts drop close to 35. This issue will occur way before the pack is low though.

Before vesctool i was using the unity app and thats where this issue started. On the unity app i usually had motor max at 80a and battery max 80a. So that was 40a per motor and i was having the cutout issue.

I need a few more test runs with current settings. Im still hoping lowering the deadband was all i needed but it still doesn’t explain why it started happening with the unity app that doesn’t allow you to change it. I was using the android unity app.

The only other explaination I can think of is hardware failure. Im hoping not.

#45

Oh and I like to ride fast and loose mmmk. I don’t want to ride a limp dick plank with no power! Lol

#46

Ok so you guys were right. It wasn’t the deadband. It happened twice last night. First time I was at a stop then I tried accelerating on a slight incline trying to cross a street and it cut out for a second. The 2nd time I was moving slow and tried to take off to merge onto a street and it happened.

Im going to lower my motor and battery maxes both to 40a each side. I feel like this is going to be sluggish but I need to see what happens.

#47

Were you stopped both times? Or were you even slightly rolling?

Did you check for faults?

Was it off (cut out) for exactly half a second, or something else?

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#48

First time I was not moving before I tried accelerating. The 2nd time I was rolling 5-10 mph.

I don’t know how to check for faults. It cuts out for half a second every time it happens. If I accelerate slower I can avoid the cut out.

#49

You need to check for faults to find the cause.

I think the answer to your problem may be up in the first reply.

I can’t find it on this forum (!!) but it can be found.

#50

I rode last night with motor and battery max at 50a each side. It faintly cut out twice. Went home plugged xenith into laptop before turning off esc and checked for faults but it said none since start-up. If I had a loose connection would it have shown a fault?

Seems like the cut out was weaker with the amps set lower. Not sure if that indicates anything. This is frustrating.

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#51

This is useful.

assuming you mean “loose connection in the motor phase wires”

Would have been very likely to, yes. Not absolutely guaranteed.

I am leaning towards this hypothesis:

Check all the solder joints on the XT90 / XT60 / power connections.

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#52

I rode today and intentionally got it to cut out a few times so I could check for faults but there were none. I opened the cover of the xenith and didn’t see any burn marks. I didn’t remove the motor cable covers but I did pull on each one. None felt loose.

I was using two sets of extensions cables for the motors but I repositioned the xenith so I don’t need them anymore. I had to recalibrate motors though but that went fine. Hot glued the shit out of the wires. Everything looks good so I’ll ride tomorrow and report back.

Maybe the issue was with the extension cables. Idk.

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#53

What did your phase wire extension cables consist of? Was it just the phase wires or sensor cables too?

#54

Just these motor cables. The other wires from the motors to the xenith were barely long enough to reach before but now they have some slack.

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#55

I bet you simply added toooooooo much motor amps. I didnt read the whole thread, but If you go sensorLESS It could be. In theory you can add much more amps to each motor, practically, too, but the behaviour of the motor changes which means you can have different kind of problems bc of that. Heat f.e. is known problem everybody knows when adding more amps than rated to the motors. You theoretically get more torque but in practice it could be that you get problems at startup or/and at high speeds (full throttle).
Try lower the motor amps and get your battery amps in a rated area, too.
Problems should fade away, no?

#56

Sag?

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#57

The battery is so big…mhhh…such a sag at start ups? Then the battery is totally trash i think.

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#58

Check the solder joints on the ESC power connector

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#59

I never notice any sag with this pack. My motors are rated for 95a each and the cut outs occur with the settings much lower.

I pulled on the power cables too. They seem to be be good but i didn’t remove the covers to be sure. I’ll look after the next test ride.

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#60

Do you mean power cable to bms/battery or the power button for the esc? One of the wires to my power button popped out so it’s not working at the moment but the wheels roll esc to start so I figured why rush to fix it?

#61

The wires that supply power to the ESC. The large red and black ones.

#62

Ok thats what I thought you meant. I’ll check that next. Thanks for all the help btw

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#63

Ok so it happened again without my motor extension cables. I pulled down the covers of all the connectors for esc and motors and the solders look good.

If my belts are too tight can that cause it to feel like its cutting out? My motors have lots of torque so i keep them tight so they don’t slip. Im running out of ideas. Maybe i just need a more powerful esc. Maybe a motor cable is loose where they go into the esc. I cant remove those to look.