That's certainly right on the Bafang BBS02 motors...I ride my 750W in power level 3 of 9 in all situations after months of trying different cadence/power levels, the cadence is relatively low to what I'm used to, but it is relentless (like a non-stoppable...erm...slug) up hills and will climb 45 degrees at a fast walking pace whilst steering round rocks etc...on a full charge it'll run 20mph and drop to 18 when the batt starts to fade, fast enough for the tracks/chutes round here.
Before I reconfigured my BBS02 I rode around in PAS 3 most of the time. It seems to me that riding in PAS 3 all the time is like putting a motorbike in 3rd gear and expecting it to perform no matter what the terrain/conditions. You're getting away with it due to the huge torque of the BBS02 48v motor. I'd suggest that adjusting the PAS to suit the trail/road conditions is a better solution. It puts less stress on the motor, controller, gearing, drive train and your legs/knees. I do understand the issues of getting the controller settings to your liking. I've found that the usual approach of "limit speed"(cadence) and "keep current" to be the culprits here.
I've configured my BBS02 500w 36v to allow high cadence so that it feels more like a normal bike using the programming cable and software referred to elsewhere on this forum. I really like the result AND I get over 3hrs in PAS 4-6 on a charge (18AH 60 x 30Q Samsung cell pack).. Mostly rolling roads, occasional +25% hills and some easy trails. I once got over 4 hrs in PAS 2&3 albeit at a slower pace, just to see how long it would run. Battery voltage was 34.5v after 60 miles! Still enough left to make it to a pub/car/home.
Here's what I've done. (Remember I have a 36v motor and if you have an older 48v BBS02 with crappy mosfets keep the cadence up, reduce the limit current and dont ride in PAS 9 all the time!)
- Fit a 42t chainring.
- Set display settings to 9 PAS levels and 50kph max speed. 29er wheel (700c) . I have the C961 display.
- In the Programming settings I've set Limit Speed to 100% in all PAS levels. You can then pedal as fast as you like...........my average is around 93rpm, but cadence is only limited by your ability to spin.
- Limit Current to 15Amps (from 25A) 15 x 36 = 540watts which is more than most professional MTB'ers can maintain for long and you can add your input to this. (say 150-300w depending on fitness)
- Start Current 15%-to protect the controller. It will feel a little slow/more like a normal bike to get going at first.
- Low start mode 4
- Startup degree 4
- Work mode undetermined
- Time of stop (x10ms) 5
- Current decay 8
- Stop decay (x10ms) 0 So that the motor stops immediately
- Keep current 100%, so the motor doesn't back off just when you need it to help a little more!
Limit Current % settings in each PAS
I dont have a throttle fitted. Suggest setting PAS 0 to 1 for both Limit current and Limit speed.
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- 40
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- 100
To start with I reduced the Limit current to 20 Amps. The bike was actually too fast, so I dropped to 18 amps, then 16amps, now I find 15amps perfect. I'm 72 kilos+ the bike is a hefty 19 kilos all up inc spare tubes, pump, water bottle etc.
I set the low PAS settings quite close so I can tune the pace when riding with others. As you go faster, wind resistance has more effect, so you need more power to increase speed the faster you go. You also need to factor in power to weight ratios. If you're heavy, you need more power especially climbing, so just go up to a higher PAS level. You'll need to reduce the PAS level when you're back on the flat.
These settings might not suit your needs, you may need to tinker with the Limit Current % in each PAS. I tend to set off in PAS 1 and go up to around 3 or 4 depending on who I'm with and how windy/hilly it is. The buety is not having the cadence restricted at all. (apart from the motors ability to assist you in a given gear, if you feel the bike bogging down and your cadence dropping, you just change down until your cadence is comfortable or increase PAS to increase the speed to match a comfortable cadence)
I am finding that my 9 speed 11-34 cassette ratios are a little wide. Sometimes I could do with another intermediate gear. Top gear is fine. (27.8mph @ 90rpm) Bottom gear is little high on very steep climbs, a 36 cog would help to keep cadence over 60rpm on the steepest climbs. ie 5.7mph. I may switch to a 10 or 11 speed setup with a 11-36 cassette. I dont think I need a 40 or 42t. I'd prefer slightly closer ratios throughout the range.
