Stromer ST2 - Technical review

[Ravi Kempaiah]

I have learnt quite a bit from reading other people's experiences on this forum. As a researcher, I enjoy learning new technologies and keeping up with the pace.

Close to 18 months ago, I put together this presentation for my own understanding but being lazy, I never published it anywhere.

This may interest people who like to learn more about the ST2 E-bike and the platform.

I have close to 20,000 miles on different E-bikes and having ridden both mid-drives and hub motors, I feel that there are + and - to both. There is no question in my mind that DD hubs are superior for high-speed cruising. I could never emulate the efficiency of an ST2 motor on Bosch/Yamaha/Brose powered bikes at 20+ mph speeds.

The following series of pictures is purely for the purpose of understanding the system better, not for any promotional purposes.

If I am missing something, feel free to add/modify.

 

[Ravi Kempaiah]

Part 2 with some more slides about the OMNI system and what I would like to see in the version 2 of Stromer ST2.

Chime in below with what you would like to see in the second version of ST2.

 

[bluecat]

What an exciting compilation, thanks Ravi!

I have close to 20,000 miles on different E-bikes and having ridden both mid-drives and hub motors, I feel that there are + and - to both. There is no question in my mind that DD hubs are superior for high-speed cruising. I could never emulate the efficiency of an ST2 motor on Bosch/Yamaha/Brose powered bikes at 20+ mph speeds.

Good to read this from somebody, who's ridden all brands.

I've publish two pics of the ST2 motor, feel free to use them to illustrate "no more controller inside"

A tech guy told me, the efficiency of the ST2 motor drops sharp above 48km/h. But for the Si2, the build a few Stromer which reach above 60km/h (they have to support the airplane)...

(BTW: The SI-special edition has only special painting, Vmax is still 45km/h)

In europe, the Magura MT5 Next e 4 piston on the ST2s is also capable making horrible noise, depending on temperature and humidity ;-)

 

[PTFC Brian]

What an exciting compilation, thanks Ravi!

Good to read this from somebody, who's ridden all brands.

I've publish two pics of the ST2 motor, feel free to use them to illustrate "no more controller inside"

A tech guy told me, the efficiency of the ST2 motor drops sharp above 48km/h. But for the Si2, the build a few Stromer which reach above 60km/h (they have to support the airplane)...

View attachment 16497

View attachment 16498

(BTW: The SI-special edition has only special painting, Vmax is still 45km/h)

In europe, the Magura MT5 Next e 4 piston on the ST2s is also capable making horrible noise, depending on temperature and humidity ;-)

Part with some more slides about the OMNI system and what I would like to see in the version 2 of Stromer ST2.

Chime in below with what you would like to see in the second version of ST2.

Thanks for your excellent research and post! I received my ST1x in April, and will post the my thoughts later this month after I put on a few more miles. Is it known whether the Cyro Drive motor is the same as the Syno Drive motor? I haven't been able to find specific information on the Cyro Drive other than it has 35 NM of torque, compared to the 40 NM of torque for the Syno Drive.

 

[Robie]

Great stuff, thanks Ravi. Kinda blurry on my phone. Hope the pics. come through better on my pc. Amazing bike,

 

[Polycarp]

Thanks for sharing, Ravi.

It’s great to hear these opinions from someone with such significant experiences on various e-bikes. You echo what most people will read when researching differences between DD and mid-drive systems. Before I bought my Stromer, I did a lot of research including test rides on a few mid-drive, full or front suspension systems, and came to the same conclusion. The Stromer I bought fit my needs best. And that's what's great about the eBike market today - so many variations for different preferences and needs of customers.

I also confirm bluecat's statement that even the 4-piston brakes (under the right conditions) squeak on my ST2s here in Switzerland.

Regarding what I would like to see in the second version of ST2 series:

1. Ability to dial in a speed limit. Here in some cities in Switzerland, certain bike zones allow only a maximum of 25km/h e-bikes. Technically, 45km/h bikes aren't allowed on the paths, or rather, the power assist must be turned off. So, I compromise, I set the power assist down to 1 or 2, and then pick a higher gear and pedal slowly, but I constantly am looking down at the screen to make sure I'm not exceeding 25km/h. So, it would be nice to have an option in the OMNI app to dial in a specific speed for the Custom setting.

2. Ability for the GPS/theft system to work without the primary battery in the bike. What I'd like to see is something like a small battery integrated into the OMNI computer on the bike. One that maintains a constant charge by being charged up from the primary battery while it is in the bike, and then once the primary battery is removed, this secondary integrated battery would have enough battery capacity to enable the GPS/theft system for say, 12-18 hours until the primary battery can be re-installed. Think of it - your iPhone or Samsung or most smartphones today have a relatively small size battery that can power the GPS and lightweight internet connectivity for 20-24 hours. Maybe the Stromer engineers can figure out a place to squeeze a sufficiently sized battery inside the frame. Why the need for this? Sometimes, I have a need to charge after my morning commute from home to the office (high wind, etc) in order to make sure I can make it all the way home in the afternoon. Likewise, when I park at home, I bring the battery inside all night for charging. In both cases, this practice of removing the battery to charge it indoors leaves the bike "unprotected" with regards to GPS/theft/tracking. Yes, I lock the bike when at work, and when at home, but we all know locks are not the only deterrent - and the Stromer tracking is supposed to be an additional little bit if "insurance". But, I'm a little miffed that the system only works when your battery is charged and installed in the bike. Yes, I knew this was how it worked when I bought it. But in reality, the impracticality of the design introduces some anxiety in the situation where we remove our batteries to charge off the bike. I would think this would be an easy and super "upgrade" for the next Stromer bike. (or, if they could create a new OMNI computer that's replaceable with the existing one for a price, I might even pay for such an upgrade!)

3. Maps and tracking. Would love to see additional metrics. I use the iOS app called Trails to map my ride and see my overall "performance". Sure, some of us are geeks about data. My point is, if Stromer could include the history of the trail/trip and associated metrics with each ride, I'd really enjoy to see that (and stop using/paying for a 3rd party app - just something else for me to launch on my phone before a ride).

Happy riding everyone!

 

[Ravi Kempaiah]

What I'd like to see is something like a small battery integrated into the OMNI computer on the bike. One that maintains a constant charge by being charged up from the primary battery while it is in the bike, and then once the primary battery is removed, this secondary integrated battery would have enough battery capacity to enable the GPS/theft system for say, 12-18 hours until the primary battery can be re-installed. Think of it - your iPhone or Samsung or most smartphones today have a relatively small size battery that can power the GPS and lightweight internet connectivity for 20-24 hours.

Great feedback! This will make it more robust. Areas that don't have cellphone network, it should still be able to connect to the GPS system and get the coordinates.

it would be nice to have an option in the OMNI app to dial in a specific speed for the Custom setting.

A small scale on the tuning bar - 25kmph ---- 30 kmph -----35kmph ------40kmph------45kmph.
You can pick any speed in-between as well. That would be nice.

I also want to see Supernova M99 Pure+ on the ST2 base model.

 

[opimax]

you stopped early on the speeds 50kph for off road use would be nice

 

[George Jetson]

As a relatively new ST2 owner, I'm still in the honeymoon phase; but here's my 2 cents' worth. To level set, I ride exclusively on big city streets in a major metropolitan area. I'd like an option to strobe the DRL LEDs. The on/off cycle for an LED consumes no more battery than constant on and would provide extra visibility to drivers around town. The US distributor should have an urban streets pre-configured version of the ST2 which comes factory-equipped with a suspension front fork w/fender and a suspension seat post or sprung saddle. I don't off-road, but the potholes, RR tracks and broken pavement on the city streets where I ride are brutal when taken at speed on a 60 pound bike (plus my less than svelte load).

Still extremely happy I pulled the trigger on this one, even after all of the hassle to get it assembled and replacing the fork and seat post.

 

[Ravi Kempaiah]

Thanks for your excellent research and post! I received my ST1x in April, and will post the my thoughts later this month after I put on a few more miles. Is it known whether the Cyro Drive motor is the same as the Syno Drive motor? I haven't been able to find specific information on the Cyro Drive other than it has 35 NM of torque, compared to the 40 NM of torque for the Syno Drive.

Hi Brian,

There are few minor differences in the CYRO drive vs SYNO drive. First, the thru-axle system is little different and 2nd, the way power cable exits the motor is also different.
Even though the top speed is similar ~28mph, SYNO drive has little more Copper mass and hence gets upto speed quicker. I don't pictures for the internals of the motor but since the platform is same, it wouldn't look much different.

If you get the 814 Whr battery, upgrade the lights to Supernova and upgrade the grips/pedals you will have ~85% ST2 at a much nicer price point.

 

[opimax]

I clean and lube my chain every ride, I think if the technology on belts is up to it I would rather have a belt than a chain, an 80% option on the charger or basically a Satiatior style charger. An accurate estimated miles left and temperature added to the display, move the display to a safer/easier to read location. I would use turn signals and brake light if they were installed. A location or accessory for a battery holder for the 2nd battery instead of my panniers. Fix the sliding seat post.

 

[Polycarp]

I clean and lube my chain every ride, I think if the technology on belts is up to it I would rather have a belt than a chain, an 80% option on the charger or basically a Satiatior style charger. An accurate estimated miles left and temperature added to the display, move the display to a safer/easier to read location. I would use turn signals and brake light if they were installed. A location or accessory for a battery holder for the 2nd battery instead of my panniers. Fix the sliding seat post.

I agree!
- A more intelligent charger to help maximize the lifetime of these expensive batteries.
- Integrated turn signals (controlled like a motorcycle). (I'm really happy the ST2s already has the integrated brake light)
- Some kind of solution for carrying a second battery that is better than just throwing it into a pannier.

 

[Polycarp]

... To level set, I ride exclusively on big city streets in a major metropolitan area. I'd like an option to strobe the DRL LEDs. The on/off cycle for an LED consumes no more battery than constant on and would provide extra visibility to drivers around town.

Great suggestion! I often see flashing LEDs on bikes as being more helpful in causing cyclists to stand out more in traffic. I almost always set my removable (knog brand) LEDs (front and rear) to strobe on my non-electric city bikes to increase my visibility to drivers.

 

[bluecat]

I agree!
- A more intelligent charger to help maximize the lifetime of these expensive batteries.

Sorry, I do not agree.

Don't trust on such "internet battery advices" - they are outdated and had belonged to people which build their own battery. The ST2 charger is state of the art. My latest advice: If you still want to use a "internet charger", do it outside of your family home.

 

[Polycarp]

Sorry, I do not agree.

Don't trust on such "internet battery advices" - they are outdated and had belonged to people which build their own battery. The ST2 charger is state of the art. My latest advice: If you still want to use a "internet charger", do it outside of your family home.

Thanks for clarifying, bluecat. There is definitely a lot of info out there about battery advice! I assumed that the Stromer chargers are state of the art and engineered as a perfect companion for all the Stromer batteries.

One thing that is probably also confusing me is some posts on stromerforum.ch. Probably my confusion is increased because I rely on Google Translate to follow the threads.

Can you clarify something for me? Some of your posts indicate the use of a timer for charging your battery. Why is that? I am probably somehow confusing internet advice with some Google Translations to come to some bad conclusion. I thought that somehow you were an advocate of only charging to 80%?

Again, apologies if I'm somehow applying something to you which is untrue. If this is the case, it is certainly my own fault.

 

[opimax]

Blue, make it a Stromer quality internet charger...if the batteries can take a faster charge at times and slower at others, if 80% helps a Stromer battery....options. This isn't complaining about what we have , the thread is what would you like to see improved. A generic request would be bigger longer batteries yet Stromers are some of the biggest already

 

[bluecat]

This isn't complaining about what we have , the thread is what would you like to see improved.

Yes, of course.

For me, 80% charging is not an improvement of battery lifetime but will result in a lack of performance of the bike. What's about a silent office/living room charger or a lightweight travel charger? How would a State-Of-Charge indicator on the charger be rated?

 

[bluecat]

Some of your posts indicate the use of a timer for charging your battery. Why is that? I am probably somehow confusing internet advice with some Google Translations to come to some bad conclusion. I thought that somehow you were an advocate of only charging to 80%?

My sole advice is: Charge only at room temperature.

A timer is enough patient to wait until the battery is cooled down from sunshine or warmed up from the icy winter. In fact, the charger works with full load up to approx. 80%, then he reduces the current until the battery is fully charged. During this final phase, the fan is usually inactive. With other words: If you prefer the partially charged battery, program the timer as necessary.

You're right, we have broad and high skilld discussions at stromerforum.ch about the battery. I can't do proper translation of all the outcome. But I'll tell you a different aspect: "Battery - 75% of capacity within 2 years" This might be the best warranty in the whole electric bike industry! They would never grant such thing, if a degraded battery would be more than a rare exception. The daily riding causes much higher demands on the battery as the charging ever could do.

 

[Ravi Kempaiah]

For me, 80% charging is not an improvement of battery lifetime but will result in a lack of performance of the bike

I wonder how you arrived at that understanding.
My doctoral research work has been understanding next gen battery materials and it is supported by NSF in the US (sort of like Swiss National Foundation). I could show any number of published research articles describing what's the ideal voltage for enhancing the longevity of the battery. It is 4.05V/cell or approx 80% charge.

If you have time, pleas watch this video carefully. This professor is a consultant for Tesla Motors and his students work for Tesla Battery group. Actually, JB Straubel (CTO of Tesla) announced a $10 million funding to his group.
In this video he explains why 80% SOC is crucial for long battery life.

"Why do Li-ion batteries die and can they be immortal?"

If you don't know, Nissan faced a multi million $ law suit for not designing their battery packs for hotter climate (AZ and CA) and their batteries used to fail prematurely and lose 30% capacity within year.
High temperature is the biggest culprits when it comes to battery degradation. Also, keeping the battery at 100% charge when not in use is NOT good.

 

[smitty]

Thanks for sharing, Ravi.

It’s great to hear these opinions from someone with such significant experiences on various e-bikes. You echo what most people will read when researching differences between DD and mid-drive systems. Before I bought my Stromer, I did a lot of research including test rides on a few mid-drive, full or front suspension systems, and came to the same conclusion. The Stromer I bought fit my needs best. And that's what's great about the eBike market today - so many variations for different preferences and needs of customers.

I also confirm bluecat's statement that even the 4-piston brakes (under the right conditions) squeak on my ST2s here in Switzerland.

Regarding what I would like to see in the second version of ST2 series:

1. Ability to dial in a speed limit. Here in some cities in Switzerland, certain bike zones allow only a maximum of 25km/h e-bikes. Technically, 45km/h bikes aren't allowed on the paths, or rather, the power assist must be turned off. So, I compromise, I set the power assist down to 1 or 2, and then pick a higher gear and pedal slowly, but I constantly am looking down at the screen to make sure I'm not exceeding 25km/h. So, it would be nice to have an option in the OMNI app to dial in a specific speed for the Custom setting.

2. Ability for the GPS/theft system to work without the primary battery in the bike. What I'd like to see is something like a small battery integrated into the OMNI computer on the bike. One that maintains a constant charge by being charged up from the primary battery while it is in the bike, and then once the primary battery is removed, this secondary integrated battery would have enough battery capacity to enable the GPS/theft system for say, 12-18 hours until the primary battery can be re-installed. Think of it - your iPhone or Samsung or most smartphones today have a relatively small size battery that can power the GPS and lightweight internet connectivity for 20-24 hours. Maybe the Stromer engineers can figure out a place to squeeze a sufficiently sized battery inside the frame. Why the need for this? Sometimes, I have a need to charge after my morning commute from home to the office (high wind, etc) in order to make sure I can make it all the way home in the afternoon. Likewise, when I park at home, I bring the battery inside all night for charging. In both cases, this practice of removing the battery to charge it indoors leaves the bike "unprotected" with regards to GPS/theft/tracking. Yes, I lock the bike when at work, and when at home, but we all know locks are not the only deterrent - and the Stromer tracking is supposed to be an additional little bit if "insurance". But, I'm a little miffed that the system only works when your battery is charged and installed in the bike. Yes, I knew this was how it worked when I bought it. But in reality, the impracticality of the design introduces some anxiety in the situation where we remove our batteries to charge off the bike. I would think this would be an easy and super "upgrade" for the next Stromer bike. (or, if they could create a new OMNI computer that's replaceable with the existing one for a price, I might even pay for such an upgrade!)

3. Maps and tracking. Would love to see additional metrics. I use the iOS app called Trails to map my ride and see my overall "performance". Sure, some of us are geeks about data. My point is, if Stromer could include the history of the trail/trip and associated metrics with each ride, I'd really enjoy to see that (and stop using/paying for a 3rd party app - just something else for me to launch on my phone before a ride).

Happy riding everyone!

nice summary...in regard to metrics...investing in a good cycling computer for a $7K - $10K bike seems reasonable. I use a Garmin Edge Touring Pro teamed up with their activity program (Garmin Express) and really enjoy both the cycling computer itself as well as their software. There is simply so much you can do with both that it makes the extra $ seem quite a quite reasonable expense. There is small learning curve to mastering terms of their software, but once accomplished makes it very enjoyable to use.