bruh
i remember frank saying this but never made the connection with duty cycle.
motor current max- low speed current
battery current max- high speed current
motor current max brake- low speed braking
battery current max regen- high speed braking
5 Likes
yes, exactly this
1 Like
And would I be correct to infer that:
High speed current = ability to maintain top speed
Low speed current = acceleration and torque
Does this look normal, Also does anyone know any videos going into detail with vesc I’m a little lost lol
The thing is we not doing a full 0-100% charge what’s maintaining max RPM. we bursting for 1-2 seconds on the brake then it’s so low it’s irrluvant due to rpm have reduced because you slowing down. (unless you coming down a super long steep hill for ages then just be aware of not over braking)
Personally I take the max fast charge the pack can take double it then devise by number of VESC’s. This is still conservative in my opinion
Eg 3p * 8(P42A) = 24A(Pack Fast Charge) * 2 = 48A(Total Amps) / 2 (qty of VESC’s) = 24A a VESC (-battry) even when braking hard I only used 80%
Your math is wrong
1 Like
Umm….exactly. For your riding circumstances it might be okay…well, not really bad is a better way to say it…but for others it can be an issue to be aware of. When talking about what’s okay and what isn’t we need to take all riders into account or otherwise list the exceptions.
But I realize what you’re saying.
It’s not just about outside cell temperature. There are hot spots inside the cell that get “smoothed out” as the heat spreads and finally reaches the outside r the cell.
Also…
Charging a 3P pack at 58A results in instant plating of lithium onto the positive part of the cell (cathode) due to the huge excess current causing the ions to bunch up at the start of the cathode. This causes a loss of performance and capacity, accelerates the aging of your pack, and can eventually lead to dendrites forming that can cause an internal short circuit (very slow discharge or huge current flow and fire…depends on lots of variables).
Dividing that 58A by the number of ESC’s is confusing me…how does that reduce the battery current? If I understand your equation it only affects how much current each ESC handles.
1 Like
The thing is it’s not a yes no line it’s a curve and as I said I personally fined it works with minimal impact on my packs and temps (all be it outside of cells) stay below 40 deg.
Any thing we do degrades the cell and shortens there life.
Charging
Storeing
Age
Discharging
Temp
Heavy loads
The thing is we looking at super high discharge cells that generally have a short life span. With frequently check for signs of degrading with smart BMS I feel what I’m doing is safe in my opinions for the reasion I have stated.
As long as people understand what they’re doing and the consequences I feel it’s more important for people to catch a failing pack than to stay above a line and never check for issues.
2 Likes
How do you edit fault time in the VESC tool mobile app? I can’t find where it is in the tabs. Thank you in advance!
3 Likes
Just seeing this 3 years after putting the Puck away! I think this explains everything! My puck was fine for about 5 miles after I installed it, then it started disconnecting and not responding and spooked me! I swapped it back to my trusty GT2B and kinda forgot about it.
3 Likes
I was checking a bunch of pucks and puck mods before esk8con, using a pwm reader (isdt mc8) and confused myself thinking the batwing was blocking full throw. turns out it was on mode 2. 
2 Likes
The only thing similar to Default ESC fault time in Metr was fault stop time. It was set to 500 which could be 5 sec. Is this the same parameter and what should I set it to?
Yeah that’s the one. 500ms. too long. set it to 75ms. some go as low as 50ms.
note that the shorter you go the less time a fault has to interrupt and throw the rider but also the less time the ESC has to recover from whatever happened. don’t go below 50ms. stay below 100ms.
2 Likes