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A project log for A Wheel

Another Satisfying Single Wheel Terrifying Hoverboard Conversion

daren-schwenkeDaren Schwenke 09/07/2022 at 16:111 Comment

Oops.  The ground line has come off of  the hall effect sensor board inside the hub.

You know how I know?  Cause as leg each of the hall sensors trigger, the wheel lights turn back on as they now have a path to ground.  Loops.

So run with one controller, hotwire across from the other controller, or break apart my epoxied hub...  I'm thinking.

I may be running into the preset current limit for the controller boards.  Either way, I don't like the value of the existing sense resistor, so we are going to change that.  3R5 aka 3.5 Ohms.  I'm running 12 gauge wires to the motors to be fed through that.  No.

I soldered some 10cm loops of 30? gauge wire across the sense resistors as I didn't have any low value resistors suitable for this.  A quick glance at the resistivity per foot for about the gauge I think this is, puts this in the range of between 0.7 and 1 Ohm of resistance.

Soldering this across the existing resistor should then be 0.6 to 1 Ohm.  I can't actually measure it right now, but it is lower and in the right range.  I need a four lead and I don't have one here, and I just jumpered across my previous known value for establishing a voltage drop at current.  :)

I am guessing that the low current limit here was not for the motors, but for the pathetic 7S-1P 2Ah battery this came with.  Had a nice BMS though..

I have ~5x that battery capacity now, and no BMS (yet).

This modification moves the upper current limit from whatever it was to ~4-5 times that.

Given the previous relatively huge value for the sense resistor, I think this will increase output.  

The existing controller mosfets, wiring, and cooling will have no issues handling the extra current.

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