0:00 Baseline test settings 20a Max Dc, 30a Max phase, WeakResponse 7:none (field weakening disabled) 1:02 Phase amps were limited to about 22a so DC amps was also held back to 18a. 1:21 Now I set 0-600 rpm ratios in speed to 50%, which covers the full rpm range of the test. 2:20 We see now Phase amps is limited to 11a (50% of what it did previously) and DC amps is held back to 3-4a 2:40 Next I raise Max DC amps to 40a to verify thats not what’s restricting phase amps to 11a. 3:13 Basically no change because the phase amps restriction (50%) is what is limiting DC amps. 3:27 Now I set DC amp limit back to 20a and increase Phase amp limit to 100a. 4:06 now we see peak phase amps approaching 50a (50% of the 100a limit because of ratios on speed) and 20a DC limit.
Ratios in Speed does ONE SIMPLE FUNCTION, limits PHASE AMPS within a certain RPM band. It can be used to: 1: Limit torque, especially starting torque where phase amps are much higher, in order to reduce tendency to wheelie or loop the bike. 2: reduce phase amps within RPM bands that have rough operation at one specific RPM and high torque. 3. It sets the speed limit when using BOOST because MaxSpeed is used for mode 3 and overridden when using BOOST. 4. Can be used to allow maximum RPM for whatever riding conditions. For example, you have a 72450 set for turn and burn (200a DC and 450a phase) and a QS motor rated at 5000w max continuous. You can set ratios in speed to taper down to 20%, which will limit max phase amps to about 90a. So if your ride is up and down hills, it allows higher speed downhill than uphill, while keeping the motor from overheating. 5. It can be used to LIMIT THE DEPTH OF FIELD WEAKENING, because field weakening needs phase amps, so if you limit phase amps, you limit how far field weakening can go. This can be done to: A. limit RPM to stay within mechanical limits of the motor, especially Inrunner motors with surface mounted magnets, when field weakening is enabled. B. Reduce battery voltage sag which reduces the need for field weakening current and can actually let you go faster. This is predominantly if you use a battery pack too weak for the controller, relying on the manufacturer’s exaggerated claims instead of what the pack can really support. If you have a cheap 72v 20ah pack, and some idiot convinced you to do a BMS bypass, and you use it with a 72450 controller, you can very easily sag the battery so far that the voltage drops from 84v to 64v, no longer having the voltage to overcome Back EMF, and now you need field weakening which would cause even more sag. So to tune the Fardriver for this weak pack until you can buy a real battery, you would first test to see the max amps you can pull that causes 0.5v/cell in series sag. So 10v sag for 20s li-ion pack. Let’s say this is 60a. You should set your max line current to 60a, for max acceleration, and then use ratios in speed to pull amps back down to about 30a DC once you are in the field weakening rpm range. For a 72450 controller this would mean Max Line 60a, Max phase 120a, ratios in speed 100% up until the RPM where “weak” first appears on the graph page of the app, then quickly taper down 100%, 75%, 50%, 25% 25% 25% 25%. The end goal to pull DC amps down to about 30a at top speed, by limiting phase amps. Then when you buy your Amorge Molicel P45B 20s10p pack, you can increase all the settings and only care about how your motor is doing.
0:00 Baseline test settings 20a Max Dc, 30a Max phase, WeakResponse 7:none (field weakening disabled)
1:02 Phase amps were limited to about 22a so DC amps was also held back to 18a.
1:21 Now I set 0-600 rpm ratios in speed to 50%, which covers the full rpm range of the test.
2:20 We see now Phase amps is limited to 11a (50% of what it did previously) and DC amps is held back to 3-4a
2:40 Next I raise Max DC amps to 40a to verify thats not what’s restricting phase amps to 11a.
3:13 Basically no change because the phase amps restriction (50%) is what is limiting DC amps.
3:27 Now I set DC amp limit back to 20a and increase Phase amp limit to 100a.
4:06 now we see peak phase amps approaching 50a (50% of the 100a limit because of ratios on speed) and 20a DC limit.
Ratios in Speed does ONE SIMPLE FUNCTION, limits PHASE AMPS within a certain RPM band. It can be used to:
1: Limit torque, especially starting torque where phase amps are much higher, in order to reduce tendency to wheelie or loop the bike.
2: reduce phase amps within RPM bands that have rough operation at one specific RPM and high torque.
3. It sets the speed limit when using BOOST because MaxSpeed is used for mode 3 and overridden when using BOOST.
4. Can be used to allow maximum RPM for whatever riding conditions. For example, you have a 72450 set for turn and burn (200a DC and 450a phase) and a QS motor rated at 5000w max continuous. You can set ratios in speed to taper down to 20%, which will limit max phase amps to about 90a. So if your ride is up and down hills, it allows higher speed downhill than uphill, while keeping the motor from overheating.
5. It can be used to LIMIT THE DEPTH OF FIELD WEAKENING, because field weakening needs phase amps, so if you limit phase amps, you limit how far field weakening can go. This can be done to:
A. limit RPM to stay within mechanical limits of the motor, especially Inrunner motors with surface mounted magnets, when field weakening is enabled.
B. Reduce battery voltage sag which reduces the need for field weakening current and can actually let you go faster. This is predominantly if you use a battery pack too weak for the controller, relying on the manufacturer’s exaggerated claims instead of what the pack can really support. If you have a cheap 72v 20ah pack, and some idiot convinced you to do a BMS bypass, and you use it with a 72450 controller, you can very easily sag the battery so far that the voltage drops from 84v to 64v, no longer having the voltage to overcome Back EMF, and now you need field weakening which would cause even more sag.
So to tune the Fardriver for this weak pack until you can buy a real battery, you would first test to see the max amps you can pull that causes 0.5v/cell in series sag. So 10v sag for 20s li-ion pack. Let’s say this is 60a. You should set your max line current to 60a, for max acceleration, and then use ratios in speed to pull amps back down to about 30a DC once you are in the field weakening rpm range.
For a 72450 controller this would mean Max Line 60a, Max phase 120a, ratios in speed 100% up until the RPM where “weak” first appears on the graph page of the app, then quickly taper down 100%, 75%, 50%, 25% 25% 25% 25%. The end goal to pull DC amps down to about 30a at top speed, by limiting phase amps.
Then when you buy your Amorge Molicel P45B 20s10p pack, you can increase all the settings and only care about how your motor is doing.