SW900 hard core tweaking

[SpencerHolst]

Greetings! I've just got myself a Chinese conversion kit with SW900 display and have been dialing in for a while. It's a 1000w 48v HUB motor installed on the rear wheel of a 20inch fold Carraro Flexi with 21 speeds.

I've got three questions:
1- Is it possible to control the voltage level of each PA step individually?

I want to get a reasonable support from all steps of PA effectively to match my speed and cadence but above a certain level of PA, I can't match the speed of the bike above PA3 ending up pedaling with zero effort.

To elaborate, P05 set to 1 for 5 steps of PA; with PA 3, the bike speeds up to 27km/h which is above the maximum speed I can get at a reasonable cadence with my maximum gear ratio. At 4 it is 35+km/h and at 5 it maxes out at 47 km/h. I want to fiddle with each grade's support somehow.

2- I can't seem to get 9 levels of PA when P05 set to 2. 1, 2 and 3 behaves the same, 4, 5, 6, 7, 8 is another group with same behavior etc. I can read the level of support changing on the screen but it does not alter the support reasonably.

3- Is it possible to download a better/newer firmware?

Thanks a lot.

 

[SpencerHolst]

Allright, please make a comment on at least the 2nd question.

 

[amberwolf]

I don't know if the controller / display set you have allows the kind of tweaking you want to do. It depends not only on the display's choice of available settings exposed to the user, but also on what the controller actually supports. For what you want to do, the hardware shouldn't affect ability of the system to do this, but the firmware in each one has to allow it.

If it doesn't, you could check some of the opensource firmware (OSFW) threads by Casainho, Stancecoke, et. al. and see if your controller and display hardware is compatible with one of them, and if the OSFW allows the kind of tweaking you want to do.


Another option is to just setup your controller to default to the maximum possible power/etc from the throttle input (so that when the system is powered on, it automatically has everything it's got available to you, without any button pushes needed), and then install a Cycle Analyst v3 in place of the display.

Then you connect the throttle (if any) and the PAS sensor to the CA, instead of the controller. The CA's throttle output goes to the throttle input of the controller. Note that if the controller cannot be configured to work without the PAS input, and be controlled by just a throttle, this wont' work and you'd need a different (dumb) controller. But most of them will work fine this way.

Then the CA can be configured to actually control the amount of power, or the speed, etc., by how fast you are pedalling. I use this to control my dual-rear-hubmotor SB Cruiser cargo trike just fine. (I do have a throttle on it for startups from a stop since I can't typically get it moving on my own without joint pain, and for the still-infrequent but increasingly-common times when I hurt too much to be able to pedal well enough to make it work).

Since the PAS control is no longer simple on/off, but actually controls the system as if it were a throttle, you don't need multiple assist levels. If you prefer them anyway, it has 3 presets you could use for that, or the digiaux control that lets you finely adjust one of a few different parameters to emulate the assist levels you're trying to achieve with the on/off system you have now.



If the SW900 display is required for any reason, you could install both, but the bars might get crowded. So you can just use the remote buttons availalbe for the CAv3 in some versions, and put the CA itself somewhere else on the bike, since you don't have to see the CA display to use it.

 

[SpencerHolst]

Will look into it, thanks for the elaborate reply.

 

[jimmyhackers]

1. no.
2. some pairings of sw900 and the controller dont have all of the functions enabled. for example, the power limit on mine does nothing, your luck may vary.
3. official updates, as far as i know, no.

 

[SpencerHolst]

Thanks mate. So much for it then.

 

[thundercamel]

I've used ebike conversion kits that came with with SW900 displays 3 times now for myself and one other person. The programming/settings are all inside of the controller, and the SW900 display just communicates with it to display speed/power and change those parameters if you're lucky. With the basic magnet wheel cadence sensor, all of the kids were far too powerful with pedal assist to actually contribute any meaningful pedaling, and I ended up just using throttle only, which is some work to modulate.

Ideally, the controllers and SW900 display would have customer support and firmware updates or the ability to adjust more settings, but that open source thread is the closest I've seen, and it is not easy. I'll be eventually replacing them with a phaserunner from Grin ebikes.ca and a cycle analyst so I can actually have support and programmability.