Shengyi Motor / battery upgrade

[Dylan S]

Just curious if anyone has any familiarity with this brand. I haven't heard of it and don't know anything about it's reputation. I'm looking at a bike which is a bit light on specs and only lists '350W Shengyi brushless motor'. It is a rear hub motor. They quoted the torque as 45.

Also, the battery is listed as an 'LG 10AH battery' with up to 50 miles range. They've offered a 13AH version with up to 62 miles range, for an extra $100. I'm thinking 50 miles is pretty good to begin with and not sure I want to pay an extra $100 for an extra 12 miles.

Anyone have any thoughts on the motor or battery?

 

[rich c]

Depending on terrain, your riding style, and your size, I'm guessing they are very optimistic with that range number.

 

[WilliamT]

My Radwagon uses a Shengyi brushless motor. As a daily bike commuter, I put it through all temperatures and weather and it has never failed on me for the last 3 years / 4500+ miles. The one I have is a 500 watt rear hub motor. It's taken a lot of abuse and has been very reliable.

The torque isn't that good but once you get going, its very smooth and quiet. To maintain the same cadence climbing hills, you'll probably need to upshift. A 10 ah battery at 50 miles sounds very optimistic. To me, 35 miles sounds more realistic.

I have a 350 watt geared hub motor with a 13 ah battery and that gets me about 50 miles using normal/eco modes.

 

[Bruce Arnold]

You might get 50 miles, on perfectly flat terrain, on a smooth-surfaced road, on a calm day, with moderate temperature (mid-60s F, 18 C), in the lowest pedal-assist setting, at around 10 mph (16.2 kph.)

With nothing to spare.

I'm basing this on a very rough rule-of-thumb that suggests that average watt-hours will be similar to average speed, so 10 watt-hours at 10 mph. If it is a 48 volt battery, 48 times 10 (amp-hours) = 480 watt-hours.

Might come up a couple of miles short, given those calculations.

If it's a 36 volt system, 50 miles is out of reach, even under ideal conditions.

 

[Alex M]

The (assumed) number 50 miles should be multiplied by 0.7, since it's not smart discharging below 20% or charging above 90%. 35 miles it is. Under ideal conditions. Since conditions are rarely ideal, you'll have to pedal a lot to get those 35 miles.

 

[Dylan S]

Thanks for all the helpful responses, especially WilliamT

What would you all do? Is $100 worth the upgrade based on the above, in your opinion? This is my first ebike so still sorting it out...

 

[WilliamT]

I think its worth the upgrade. I have an 11.6 ah and 13.5 ah battery. For me, under 30 miles I'll use the 11.6 ah (now probably more like 10ah over 3 years and hundreds of recharging). Over 30 miles, I'll go with the 13.5 ah.

With the larger battery, you don't have to charge it as much so hopefully it will last longer. Also, there are times where I'm just tired and have to up the assist. The extra watts really helps there.

 

[Alex M]

Might want to "upgrade" the motor as well. Which would mean, getting some other motor brand. From what I hear, Shengyi direct drive has chronic issues with speed sensor.

 

[Roy Boy 3]

My Radwagon uses a Shengyi brushless motor. As a daily bike commuter, I put it through all temperatures and weather and it has never failed on me for the last 3 years / 4500+ miles. The one I have is a 500 watt rear hub motor. It's taken a lot of abuse and has been very reliable.

The torque isn't that good but once you get going, its very smooth and quiet. To maintain the same cadence climbing hills, you'll probably need to upshift. A 10 ah battery at 50 miles sounds very optimistic. To me, 35 miles sounds more realistic.

I have a 350 watt geared hub motor with a 13 ah battery and that gets me about 50 miles using normal/eco modes.

I was wondering if you live in Canada because in the US it should be a 750 watt motor. I live in the u.s. and found out I have a 500-watt motor. they sell the bike as a 750 watt Hub motor. Bit of a discrepancy wouldn't you say