BBS01 Controller Upgrade 36V to 48V

[dorndi]

My plan/project worked well.
36V BBS02 runs fine with 48V.
Also tested full gas (25A) for a short period of time with the full battery. Peak power consumption about 1250W.

Runs quite fast - happy with the result. Love the fact that it spins much faster.
So I can pedal with anormal high cadence of ~90rpm through the woods and can use thumb throttle for full power and the motor is fast enough to help me to pop a wheely.

 

[krankie_cbr]

With apologies for resurrecting this thread (but hey, it's Easter!)...

I'm hoping to apply the diode mod on the wire to my DPC-18 display on my BBS01B system so I can use a 48V battery. But I'm having trouble understanding the rationale for choice in diodes... (entirely possible I'm not quite understanding how diodes work)

1) Why a TVS and not a Zener diode? The TVS seems more suited for protecting a circuit from large transient spikes in voltage, whereas the Zener is more suited for a relatively stable (and more precise) voltage step-down function.

2) In the mod threads posted previously there are large differences in standoff/clamping voltages of diodes used. For example, the diode use by Wizzeros (52V battery) was 14.3V/21.2V whereas RayGO1 (36V lithium-ion battery) used a 5V/7.5V.

Now, am I correct in understanding that the clamping voltage for a TVS defines the maximum voltage that the display will 'see'? And if so, why did Wizzeros observe 43V on their display when using a TVS with 21.2V clamping voltage? I must be missing something...

 

[amberwolf]

Now, am I correct in understanding that the clamping voltage for a TVS defines the maximum voltage that the display will 'see'?

If it's wired across (parallel to) the battery +/- then anything that clamps down to a specific voltage would cause the entire battery bus it's in parallel with to be drawn down to that voltage, and all the excess power would have to be absorbed by (and radiated as heat by) that device.

If it's wired in series with the battery positive to the display, then the voltage it's designed to clamp to would be across the device, and only the remaining voltage would be available on the other side of it (at the display, and then also at the controller's brain as fed from the "ignition" wire).