DIY E+/P+

[Jason McNeil]

DIY Ninebot P+
WARNINGS & DISCLAIMERS: IF YOU TRY THIS IT WILL INVALIDATE THE WARRANTY, RISK OF DAMAGING CONTROL-BOARD, INJURY, DEATH, KILLING CHILDREN, STARTING GLOBAL WARS...

Tired of waiting to upgrade you Ninebot E, or E+? I had the idea of connecting a 67.2v 32cell back in the Ninebot battery bay. With the cover it's a bit tight, but easily doable with a custom pack (this is 4 more cells than the standard 55.5v pack)

I wasn't sure if the control-board would detect an 'over-charge' condition & prevent it functioning normally; powered it up & it seems to work perfectly well.
App connectivity reports the correct voltage, 67.2, there's an alarm condition but doe' not effect operation.

Is the performance better with the larger pack?
Yes, there's definitely better acceleration, less sloppiness in the pedals. At the top speed, you still get the audio alerts & tilt-back, but considering you can probably buy a decent upgraded pack for a couple hundred, might be worth exploring a mod, especially for the underpowered E, C, & C+.

[esaj]

Tired of waiting to upgrade you Ninebot E, or E+? I had the idea of connecting a 67.2v 32cell back in the Ninebot battery bay. With the cover it's a bit tight, but easily doable with a custom pack (this is 4 more cells than the standard pack)

I thought the original was 15S2P? So 2 cells more (30 vs. 32)?

 

I wasn't sure if the control-board would detect an 'over-charge' condition & prevent it functioning normally; powered it up & it seems to work perfectly well.
App connectivity reports the correct voltage, 67.2, there's an alarm condition but doe' not effect operation.

Is the performance better at higher voltages?
Yes, there's definitely better acceleration, less sloppiness in the pedals. At the top speed, you still get the audio alerts & tilt-back, but considering you can probably buy a decent upgraded pack for a couple hundred, might be worth exploring a mod, especially for the underpowered E, C, & C+.

If it works ok with 16S, I wonder why Ninebot then decided to go with 15S? Do you think there could be components that cannot handle the higher voltage for longer time? The voltage difference in real life isn't THAT big, at nominal 3.6V/3.7V, 15S = 54V/55.5V, 16S = 57.6V/59.2V (usually rounded to 60V), at maximum of 4.2V, 15S = 63V, 16S = 67.2V. 

As for acceleration, I have somewhat managed to wrap my head around the DC motors, and I've understood that the current to the motor is controlled/caused by the potential (voltage) difference between the average voltage from the PWM pulses and the back-EMF of the spinning motor. The faster the motor spins, the higher the back-EMF. If the voltage from PWM is higher than the back-EMF, the motor will accelerate, if it's exactly the same, the motor will "coast" (current = 0A, basically no torque) and when the back-EMF is higher, regenerative braking can be done (or the energy must be otherwise spent, if the motor is to be slowed down faster than just rolling friction/air resistance allows). If the Ninebot motor driving PWM-logic doesn't "tune" itself (at least that much) to the higher voltage of the batteries, the potential difference "seen" by the motor will be higher due to higher PWM-voltage, and thus current will be higher, causing higher torque, causing faster acceleration...

[Jason McNeil]

Hey @esaj, you're right, the original pack is 30cells, had 55v printed on the original battery pack (which threw me off) but the charger is 61v. I believe the improved performance is probably owing to more Amps available in the King Song pack, as you say, voltage to the motor is regulated by the PWM controller. 

As a lab test, it would be interesting to know what 67.2v translates into RPMs with this motor under no-load—probably way beyond the 20kph limiter, but not enough torque to support a rider safely.  

No idea why Ninebot opted for this 15S2P config, in these early tests there doesn't seem to be any intrinsic issue with over-voltage. Maybe they took the conservative engineering approach, didn't want to stress the controller too much... Time permitting, I'll perform some proper hill climbing tests with the eLogger.

[Guest]

DIY Ninebot P+
WARNINGS & DISCLAIMERS: IF YOU TRY THIS IT WILL INVALIDATE THE WARRANTY, RISK OF DAMAGING CONTROL-BOARD, INJURY, DEATH, KILLING CHILDREN, STARTING GLOBAL WARS...

Tired of waiting to upgrade you Ninebot E, or E+? I had the idea of connecting a 67.2v 32cell back in the Ninebot battery bay. With the cover it's a bit tight, but easily doable with a custom pack (this is 4 more cells than the standard 55.5v pack)

I wasn't sure if the control-board would detect an 'over-charge' condition & prevent it functioning normally; powered it up & it seems to work perfectly well.
App connectivity reports the correct voltage, 67.2, there's an alarm condition but doe' not effect operation.

Is the performance better with the larger pack?
Yes, there's definitely better acceleration, less sloppiness in the pedals. At the top speed, you still get the audio alerts & tilt-back, but considering you can probably buy a decent upgraded pack for a couple hundred, might be worth exploring a mod, especially for the underpowered E, C, & C+.

Can you provide a link to where i can buy the battery? Have you came across any issues since you used it? Did the connectors fit the  nb1 or did you have to mod it? Where you saying that the orginal battery cover was possible to use but it will be a tight fit, or can it only be used with a custom battery cover?

[SuperSport]

Hey Jason.  Any updates on this?  Did you leave this battery in place, and did you ever cook a motherboard?

[Jason McNeil]

That one is back in London. Worked pretty well at 67v, I might send over this control-board to do some more testing in a newer 9B1 testing Wheel.