Moscow plus c7 display confusion

Silvercat

Member
Hi,
Confused regarding C7 display on my Moscow Plus. With a fully charged battery, I rode approximately 30 km with voltage indicating above 50. Basically flat terrain. All 4 battery lights were still on, as was the 5 bars in the display.
On my ride home, I climb a fairly steep hill for about 1 km. On the steepest section, with my PAS at 5 (6 is max) and my front derailer in the middle ring (3 rings in all) and my rear derailer set at gear 2 (out of 8), my max speed on the steepest section (a distance of approximately 250 feet), is about 10kph. Of course, I am pedalling as well (and praying my battery does not die!!).
I noticed the volts had dropped to about 45-46 (at that time, I had rode about 45 km). I heard a knocking sound from my rear hub, as if something was not right. Changing to a lower or higher PAS did not stop that knocking sound. Only stopped once I reached flatter ground. Power seemed much weaker. Must be a connection to the lower battery voltage.

When I completed my ride, covering 51 km, I was down to 2 lights on the battery. (Charging battery now).

Any suggestions would be appreciated re whether my experience is normal or not. Perhaps a battery issue? I have only 700 km on my bike.

Thanks everyone...most appreciated!
 
I think that if you are going that slowly you need to drop down the PAS to a lower level, say 1 or 2. The PAS levels are very much speed related on the NCM (and most hub drives) rather than torque or true cadence related. Were you going that slowly because you felt like you were losing power or was it just because of the steepness of the hill?
 

Silvercat

Member
I think that if you are going that slowly you need to drop down the PAS to a lower level, say 1 or 2. The PAS levels are very much speed related on the NCM (and most hub drives) rather than torque or true cadence related. Were you going that slowly because you felt like you were losing power or was it just because of the steepness of the hill?
Thanks for your reply. I was only able to reach about 10 kph while in PAS 4 and 5 using low gear...middle sprocket in the front and sprocket 2 and 3 in the rear (low gear). The steepness of the hill but also felt I was losing power so had to pedal harder to maintain that speed of only 10 kph on steepest section (about a 45 to 60 degree climb).
If I drop the PAS to level 1 or 2, I would be very concerned about having enough power to move forward.
I thought a higher PAS level means more power assistance to climb.

Appreciate any further suggestions.
Thanks!!
 
My experience of the NCM power assist levels has always been that they are basically just speed limited; so PAS 6 cuts out around 25 km/h but offers assistance all the way up to that level, PAS 5 cuts out around 22 km/h, PAS 4 @ 18 km/h and so on all the way down to PAS 1 which cuts out around 10 km/h. I believe that they all offer the same assistance up to the speed at which they cut out but some users have reported that they feel as if they are getting less assistance at lower speeds from the higher PAS levels. Also you have the issue that you may be pushing more power through the motor than it can use if you use the higher PAS levels at a lower speeds - potentially risking overheating the motor. I believe that the advice is that you should reduce the PAS level to the appropriate level for the speed you are doing. I never really worried about that as I was rarely doing less than 25 km/h. The other issue that you may have is that you may be pedaling at BELOW the minimum cadence for assistance if you are not dropping the gears low enough. The gear that you suggest that you are in would I think require a cadence of just less than 50 to be going at 10 km/h. I don't know what the cut off for the minimum cadence is but I would hope that it would lower than that.
 

Silvercat

Member
My experience of the NCM power assist levels has always been that they are basically just speed limited; so PAS 6 cuts out around 25 km/h but offers assistance all the way up to that level, PAS 5 cuts out around 22 km/h, PAS 4 @ 18 km/h and so on all the way down to PAS 1 which cuts out around 10 km/h. I believe that they all offer the same assistance up to the speed at which they cut out but some users have reported that they feel as if they are getting less assistance at lower speeds from the higher PAS levels. Also you have the issue that you may be pushing more power through the motor than it can use if you use the higher PAS levels at a lower speeds - potentially risking overheating the motor. I believe that the advice is that you should reduce the PAS level to the appropriate level for the speed you are doing. I never really worried about that as I was rarely doing less than 25 km/h. The other issue that you may have is that you may be pedaling at BELOW the minimum cadence for assistance if you are not dropping the gears low enough. The gear that you suggest that you are in would I think require a cadence of just less than 50 to be going at 10 km/h. I don't know what the cut off for the minimum cadence is but I would hope that it would lower than that.
Hi,
Thanks very much...appreciate your comments. Confused re what you mean by “a cadence of just less than 50” ? Also, would you recommend I use the lowest gear and keep my PAS around 2 or 3?
I do try pedal fairly hard but I sure am far (about 4 decades) from my university hockey playing days! Lol.
Thanks again!
 
Hi,
Thanks very much...appreciate your comments. Confused re what you mean by “a cadence of just less than 50” ? Also, would you recommend I use the lowest gear and keep my PAS around 2 or 3?
I do try pedal fairly hard but I sure am far (about 4 decades) from my university hockey playing days! Lol.
Thanks again!
Cadence is the number of revolutions per minute of your chain ring as opposed to the speed you are actually traveling. My preference is always to keep my cadence as high as is comfortable for me (approx 90 to 100 in my case) and then change gear to suit the speed I am going. That should not change whether you are going up a hill or down one.

You say you try to pedal fairly hard but that may be your downfall. Try instead to pedal fairly easily, but faster. If you can get yourself used to "spinning" at a cadence of 70 or more then climbing (and everything else) should feel easier. Of course there is a saying in cycling that it doesn't get any easier, it just gets faster. Don't be concerned about changing down to lower gears - even the smallest chainring at the front as long as it means you can comfortably maintain your cadence. Try to adjust your PAS levels (roughly) according to the speed you are going but concentrate more on a consistent cadence than anything else.

Have a look at https://www.bikecalc.com/speed_at_cadence for an idea of the speeds you could expect at various cadences. You can plug in the figures for the Moscow Plus front and rear gear combinations.
 

Silvercat

Member
Cadence is the number of revolutions per minute of your chain ring as opposed to the speed you are actually traveling. My preference is always to keep my cadence as high as is comfortable for me (approx 90 to 100 in my case) and then change gear to suit the speed I am going. That should not change whether you are going up a hill or down one.

You say you try to pedal fairly hard but that may be your downfall. Try instead to pedal fairly easily, but faster. If you can get yourself used to "spinning" at a cadence of 70 or more then climbing (and everything else) should feel easier. Of course there is a saying in cycling that it doesn't get any easier, it just gets faster. Don't be concerned about changing down to lower gears - even the smallest chainring at the front as long as it means you can comfortably maintain your cadence. Try to adjust your PAS levels (roughly) according to the speed you are going but concentrate more on a consistent cadence than anything else.

Have a look at https://www.bikecalc.com/speed_at_cadence for an idea of the speeds you could expect at various cadences. You can plug in the figures for the Moscow Plus front and rear gear combinations.
Hi,
Thanks again for your very helpful comments. I certainly do not have your level of understanding nor would I pretend to. I will follow your advice.
Interesting to read your comment about no difference if going up or down a hill. When I ride down a steep hill, approximately 1km in length, near my house, I do not need to pedal, I just feather the disc brakes to ensure I do not hit too high a speed. I have reached 63 kph, which clearly was not comfortable...too fast. Around 50 to 55 kph max seems fast enough to maintain control. I just had to surpass 59 Kph! Never again!
Thanks again!