On Fri, 7 Aug 2020 15:19:59 -0700 (PDT), wrote:

snip

On a footbridge with ramp, the scooter would freewheel down at about
1mph, so if mum got off it and wasn't careful, it could run (well,
'stroll) away. At least I know we can carry on safely testing it in
the meantime. ;-)

The electromagnetic brake covers:
braking on steep slopes

'Stopping and staying stopped' on steep slopes, as this is a digital
thing?

secondary braking mechanism in case the primary fails

The primary braking in this case is the motor overrun, then the
electric brake (not sure if it cuts in instantly or has a delay by the
controller, I believe the latter).

parking/mounting/demounting brake

Now that it is 100% because I see it more of a parking than stopping
brake etc.

If you let off from full (Slow) speed it comes to a halt (on the flat)
in about 500mm and that's *only* whatever breaking effort is applied
by the motor (electric brake disconnected, hand brake not used). Now,
the motor could well be shorted (or low resistance) by the controller
under those circumstances and hence providing quite a lot of braking
force in any case. It wouldn't hold it on a slope of course.

The scooter his do one ~5 mile trip (on a very hot day) and with a bit
of 'off road use without an issue and only using 2 of the 8/10 'fuel
gauge' bars.

The PO reported very low range so the chances are this electric brake
has been faulty (and getting worse) for a while. The worry is that
whilst the Rhino controller is supposed to be very well equipped with
all sorts of overload condition overrides, it (and the motor) may well
have been run hot for a while.

Anyway, on the last trip it was fine from here to Mums (.5 mile) but
apparently hesitated once soon after Mum got on it and then cut out
completely once in the local park (about 1 mile total that trip).
Everything was live, including the reversing indicator, just no power
to the motor. I got Mum off the scooter (she can walk short distances
/ stand ok) I removed the seat and motor / battery bay cover but
couldn't see anything loose. I disconnected the main 24V battery
connector and re-connected and then the motor 'pulsed' in response to
the throttle and about 30 seconds later it started working again.

It was fine round the park and back to Mums ... and again from hers to
ours and then seemed to cut out up to the crossover here where it
seemed to cut out again (same symptoms).

Not been back to it since to see if the fault has cleared itself.

I now have access to the Rhino speed-controller installation, wiring
and configuration manual and so if the fault has remained I have a
better chance of diagnosing what and where.

I can get a brand new electric brake from Taiwan for £50 plus any
import duties / tax or a second hand one here for £65. One of the
things I'm not sure about is if the faulty electric brake, fitted
electrically but not mechanically functional is still having an impact
on the situation. If there was something wrong (especially
intermittent) with the electric brake coil ... where it was going open
or short circuit, those I believe are picked up as fault conditions
and would inhibit the controller (5 flashes of the fault light or 1).

The dichotomy is if it isn't to do with the brake but say the
controller itself, we don't want to be spending any more 'real' money
on it, over say a newer s/h or new one (not that they would be immune
from issues either of course).

The coil measured 40 ohms that I believe is about right so I wonder if
I could replace it with a 40 ohm (12W, the rating marked on the brake)
resistor?

Cheers, T i m