Would be curious how often you’re pulling anything near 80A would really be good to get some metr data to see how long it’s staying at high amps. Personally would be concerned about the nickel strips burning up and taking cells with them (chain reaction). Think while things are acting weird till you replace motor or get more data on why the nickel strips are failing would reduce that max amperage. Also I’m a small guy on flat land but I never pull that many amps (single drive 6374 149kv turnigy sk3, 10S) https://metr.at/r/GLCvO
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Well, here is some data from last time it saved properly. During this run, the board got really slow near the end and it was the last time FOC mode was working correctly. I then fixed the battery (was only charging to 60% and had a break in nickle and bad pack). When I rebult it all, FOC mode was stuttering hense this thread. As you can see at the beginning of this run, its only at 37.8 on full charge (10s4p). So, the break in nickle happened in a previous run. I didn’t notice it as it kept running ok on what was essentially 9s.
Could it be a shorted motor? I’ve heard of similar issues but on a hub motor… (Motor barely turning, cogging, super hot to touch, focbox extremely hot. I’m not an expert!)
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I dunno. Motor works to an extent. Dunno if shorted motor would work at all.
The shorted one also worked to an extent… it would just burn through battery like nothing else…
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How did short?
As far as I understand, something inside the motor broke and shorted. It wasn’t anything you can fix externally
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So, Ive repaired the battery today. What a pain!! Like surgery. Anyway, its now fixed and charging to 100%. Interesting… there was no break in the nickel. It didnt blow! I’m going to now blame the BMS for the dead pack. I was gonna replace it last time I has a bad pack but because I thought I saw a break in the nickel, I blamed that and didn’t replace the BMS.
So, BMS is replaced. We’ll see if it holds out.
I still have stutter in FOC mode and BLDC is totally fine. Here is a metr stat from today in BLDC mode. All mostly flatish ground in 28C deg heat. Motor was quite warm at the end.
Anyone see any issues that might hint at the warm motor and the FOC stutter?
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Does your motor have a temp sensor? Because I can see it in the graph. The graphs look fairly normal to me, maybe your just to heavy for a single, or too much of a speed junkie for this setup.
The focbox does get pretty close to 80c near the end.
Why it only stutters in foc suggests the issue is in the foxbox.
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Yeah, I’m about 160lb. Maybe I just need a double setup. I have a Maytech vesc in another build that I might put in this for an hour to see if FOC works ok with my current motor. It has different size bullets connectors so I’ll have to make adapter cables.
Its so hard to keep track of my setups and figure out when it all went wrong…
15/36T with Maytech Vesc (83mm, 90mm and 100mm wheels) 15/42T with FOCBOX (83mm, 90mm, and 100mm wheels)
Flat smooth park ground, my fav was 15/42T with FOCBOX 83mm wheels. HUGE torque but maxed out at 20 mph.
Truth is, the best by a mile on various surfaces is 15/42T with FOCBOX 100mm MBS. Very acceptable torque and still 25mph. It just hammers over sticks and stones with ease and very little vibration. I just wish I had FOC mode working again!
I experience a stutter at hard acceleration aswell. So far swapped motors, focboxes, made a second set of phase wire extensions, tried foc - bldc, vesc tool, bldc tool. Nothing makes a difference. Battery seems to be fine as it charges normally. Motor turns without a problem and it’s smooth. Using 30qs and supower bms as well as an anti spark switch. These are the ones left to change but I feel like I won’t bother anymore it’s not a major issue.
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Sounds like a PITA. Yeah, mine is currently fine in BLDC mode. If I knew a simple fix to get FOC working again I would do it but Im fed up trying now.
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those batteries look weird. i havnt’ seen such markings till now, the others look normal. source legit? Also is your motor with or without sensors?
The source for those 30Qs was www.18650.uk The kinda white marks on them is glue residue. The motor is sensored, yes.
For my second build I will use different motor, bms, battery brand, simple xt90 anti spark, motor mount etc and see if the problem persists 
Try swapping the remote and receiver?
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Hey Guys,
I had the problem where if you try to pull the throttle trigger hard from a stop or a really slow roll then it stutters.
Here’s how I fixed it:
STEP#1: I went in to the FOCBOX UI, went to “Remote Config” > “Advanced Throttle Config” > “Positive Throttle Ramping Time” > (Increase from 0.30 to 0.55 seconds.)
STEP#2: I went in to the FOCBOX UI, went to “Remote Config” > “Advanced Throttle Config” > “Negative Throttle Ramping Time” > (Increase from 0.10 to 0.25 seconds.)
STEP#3: While You are in the FOCBOX UI, “Remote Config” > “Advanced Throttle Config” menu, try setting your “Traction Control” = (Disabled).
I think STEP’s #1 and #2 will solve your problem, but Step #3 is how I have mine so might want to try your Traction control setting to Disabled also.
*Like I mentioned, changing the Positive and negative throttle ramping time fixed my off the line stuttering problem. My thinking at the time had been, if I am at a standstill or moving slow, and I try to hammer the throttle, the board will be unable to achieve the acceleration that I am specifying with the throttle in the time allowed for that acceleratin to be achieved as specified by the positive ramping time. So I gave the acceleration a little more time to achieve the setpoint input from the throttle. I.E. 0.55 seconds instead of 0.30 as comes default on Focbox. this means the current to the motor will be applied a little more slowly also.
However, to the rider, the difference between 0.30 seconds and 0.55 seconds isnt much. But to the controls, it means almost twice as much time to complete the change from a stop to the acceleration set point being specified by the Throttle Trigger. So try that. Might even go out to 0.60 seconds on the Positive Throttle Ramp to see if the stuttering is reduced.
Or, if all else fails, apply the throttle a bit more gradually from a slow speed.
Have a nice day.
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