January 27, 20215 yr Hi I have recently converted my Norco Threshold using a Bafang BBS02 mid drive 36v 500w. I also have a Trek FX hybrid which i converted with a rear hub motor again 36v 500w. I am finding that the battery drains quickly on the Norco far quicker than on my Trek. The batteries are Hailong 36v 15.6 ah and a 36v 15ah The hub motor on the Trek allows me to commute to work for 2 days approx 16 miles per day so about 32 miles before charging the battery. The mid drive on the Norco allows me to travel around 24 miles before it is drained. Is this normal? The specs are: Trek 21 speed 11 - 32 48/38/28 crank Norco 10 speed 11-32 46 tooth crank Both have thumb throttle but i only use this to occasionally set of from traffic lights i pedal and use pas level 2/3 but sometimes use level 5 on steep ascents. Any ideas why the mid drive drains the battery quicker Thanks
January 27, 20215 yr Author Could be down to the controllers? Which do you have? sjpt The Bafang is a C 961 controller and the Hub motor is a KT LCD 3
January 27, 20215 yr Those aren't controllers but displays/LCD's. The controller id the pcb/brains of the bike, what are the current rating of the controllers ?
January 27, 20215 yr If you completed the journey on both bikes in the same time with the same pedal effort, the range should be more or less the same. If you complete the journey in less time on one bike, then that one should drain the battery faster. The next consideration is whether you're using the Bafang efficiently. you get more torque from it when pedalling slowly, but that's not very efficient. You need to keep pedalling over 60 RPM. I'd guess that around 75 rpm is probably the most efficient. Can you easily swap the batteries over to eliminate them from the equation? Apart from the range, which motor do you prefer and why?
January 28, 20215 yr Author Those aren't controllers but displays/LCD's. The controller id the pcb/brains of the bike, what are the current rating of the controllers ? The hub motor is rated at 20A the mid drive is 25A
January 28, 20215 yr The bafang is pulling 750watts + in short bursts , do the battery packs have the same cells and are the speeds similar
January 28, 20215 yr Author If you completed the journey on both bikes in the same time with the same pedal effort, the range should be more or less the same. If you complete the journey in less time on one bike, then that one should drain the battery faster. The next consideration is whether you're using the Bafang efficiently. you get more torque from it when pedalling slowly, but that's not very efficient. You need to keep pedalling over 60 RPM. I'd guess that around 75 rpm is probably the most efficient. Can you easily swap the batteries over to eliminate them from the equation? Apart from the range, which motor do you prefer and why? Hi Vfr400 i have swapped over the batteries and it does not make much difference. The hub motor seems smoother on take off compared to the mid drive seems to launch then top out. I run a Garmin edge 510 and see the data live so my cadence is usually between 70 - 85 rpm The hub seems to give a higher top speed this may be due to the difference in gearing, the mid drive as you say is more torque'y At the end of the day it gets me out riding its just frustrating the mid drive eats more power
January 28, 20215 yr its just frustrating the mid drive eats more power It won't if you turn down the power!
January 30, 20215 yr Author Has the BBS parameter's been changed at all by programming. No the mid drive is as it came
January 30, 20215 yr Solution, use a programming cable to tweak a setting or two, then enjoy. I'd start by dropping current limit down about 5 amps on the 'Basic' tab, in the programming software.
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