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Power Reduction

2,527 bytes added, 02:24, 31 March 2020
link update
This describes any riding situation where the relationship between throttle input and power is diminished.

;Effects
* The rate of power onset with throttle input is reduced.
* The limit of power at full throttle twist is reduced.

;Potential Causes
* The direct cause is typically current limiting by the [[MBB]] and/or [[Gen2/Motor Controller|controller]].
* '''Low battery voltages''' at low SoC can trigger current limiting.
*: Power (kW) = Current (A) × Voltage (V)
*: So, a given power demand will require more current at low voltage than at higher voltages.
*: The MBB and/or controller typically impose current limits on the main power bus for performance models (SR, DSR, FX, and FXS) at SoC below roughly 40%.
*: Very low voltages (below 96V?) will trigger significant power reductions.
* '''Cold battery temperatures''' can trigger current limiting, since internal resistance rises at low internal temperatures.
* '''High battery temperatures''' can trigger current limiting directly.
*: The MBB will limit current to reduce internal heating of the battery.
*: Often, very hot ambient temperatures can reduce the battery's ability to cool itself while riding, which makes this condition easier to trigger.

;Potential Solutions
* For '''low battery voltages''', charge the bike to get more/full power.
* For '''low battery temperatures''', riding at slow speed while monitoring battery temperature can raise its temperature until the condition clears.
* For '''high battery temperatures''', successive year builds of the battery typically offer lower lower internal resistance.
*: Basically, a newer bike will be more robust against current limiting conditions by not heating up as readily.

;References
* From EMF:
<blockquote>
: ... higher internal resistance of the battery at colder temperatures causing current limiting, ... It can be a little disconcerting when this happens right as I am trying to overtake slower vehicles.
: You can even see that in the logs.
:: You'll see entries <code>discharge current limited (XX%)</code>.
:: That tells you the percentage the power (=battery current) has been limited to, because of the high voltage sag due to higher internal resistance because of the cold.
: Right behind that you will read a <code>MinCell</code> entry
:: this one tells you which cell was the weakest and caused the limitation and with what voltage.
: The limitation of power is directly related to topspeed, as you need more power the faster you ride.
</blockquote>

[[Category:Performance Issue]]

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