How's your Stromer Battery holding up?

JoePah

Well-Known Member
Not real pleased with how the battery is degrading and wanted to know how others are doing.

Bought my Stromer (leftover Elite model) 36v11ah, Jan 2014. Maintain it by the book, rarely let it reach the lower voltage cutoff. Sits in my Miami garage.

After 3000 miles, and 18 months, and no idea how many charge cycles, would say my range is down by 20%. I've lost around 15 lbs over this time. My 30 mile range in PAS PWR is down to under 24.

At this rate the battery will degrade to around 60% after 3 years, and need replacing... My old A2B metro lasted 5 years.

Seem like a short life cycle.

Anyone feel the same?
 

opimax

Well-Known Member
I got 3-4 years out of my purple batteries, range didnt decrease too much but they would start turning off up hill(big power draw) at 30%+ instead of 10%, then 40% then flats , ran them on eco would work for a while more , now they site , recharge ever couple months(cause I can) waiting for a rebuild
 

EbikeR2

Member
Not real pleased with how the battery is degrading and wanted to know how others are doing.

Bought my Stromer (leftover Elite model) 36v11ah, Jan 2014. Maintain it by the book, rarely let it reach the lower voltage cutoff. Sits in my Miami garage.

After 3000 miles, and 18 months, and no idea how many charge cycles, would say my range is down by 20%. I've lost around 15 lbs over this time. My 30 mile range in PAS PWR is down to under 24.

At this rate the battery will degrade to around 60% after 3 years, and need replacing... My old A2B metro lasted 5 years.

Seem like a short life cycle.

Anyone feel the same?
nice job on the 15lb haircut! Due to increased activity?
 

CptPalmer

Member
A rebuild in these batteries should be not too painful. I know both batteries contain 50x of 18650 size batteries. The purple one uses Samsung ICR18650-22P 18650 batteries and the gold one uses Samsung INR18650-30Q 18650 batteries. I have not pulled any of my batteries apart to see if the cells are held in place with a frame or if they are all spot welded together but I am thinking the prior. The batteries are setup in a 10s5p configuration. But if you are not the DIY type you could always purchase the cells and find someone to do the work. The cells would cost approx. $200 which is far less then buying a new battery.
 
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I have two gold batteries and alternate the two. I live in Orlando and ride my Stromer ST 1 like a road bike. Rides average 40-50 miles averaging 18-20 mph. I always ride in ECO mode, once in a great while CITY mode if I'm with a faster group. I'm getting 70-80 miles per charge. My weight is 140 lbs. and no extras on the bike. I have 5000 miles on the bike between the two batteries and haven't seen any degradation yet. I ride in Central Florida where it is flat so my range is going to be good compared to someone in a hilly area. I do ride in the North Georgia mountains two months a year and I get about 45-50 miles per charge in that terrain. Hope this gives you some comparison.
 

JoePah

Well-Known Member
@EbikeR2 The Stromer helped wean me off eBikes and onto road bikes... I stepped down on the PAS until I was in good enoiugh shape to ride 20 miles on my single speed and the weight came off.. Pretty nice bike overall! and I still ride it in the summer and for commuting.
 
JoePah.. Good for you. I ride my tradition road bike also but at age 69 I can't keep up with the kids anymore without the Stromer. I have my sensitivity set at 30 and ride in ECO to keep the cardio up and calorie burn about what it would be on the road bike. The great thing about the Stromer is you can go fast when you want to. Good luck with the batteries, the have a three year, 1000 cycle warranty which I thought was pretty darn good.
 

topcatken

Member
My 2014 Elite has 500 miles but not all were with the battery in a power mode. Just in neutral frequently. I notice my battery shows a loss of a bar and 5% almost instantly. I have asked Stromer to troubleshoot but when they do reply it has not been helpful. My battery was a purple replacement for a gold which mysteriously discharged after 60 miles. Also, yesterday when my battery showed 58%, I got no power assist in any mode. I came home and charged it and it worked today. Any help/advise on the complete loss of power and the initial loss in percentage? I also have heard that leaving the charger on causes no harm but Stromer says the charger must be removed within an hour after it hits full charge. What is the truth?
 

CptPalmer

Member
My 2014 Elite has 500 miles but not all were with the battery in a power mode. Just in neutral frequently. I notice my battery shows a loss of a bar and 5% almost instantly.
I have seen this from day one and this is with both my batteries. My percentage drops from 100% to 95% quickly and then just steadily decreases until it hits 10%. I think this is due to the battery technology that is being used. If you could graph the battery discharge there is a sharp curve at the beginning and end of the battery capacity with a gradual slope in the middle. It is my understanding this is very typical of Lithium Nickel Cobalt Aluminum Oxide technology. Here is a graph that shows what I am talking about
 

JoePah

Well-Known Member
@topcatken Your first battery failed at 60 miles and now youre having problem with your second battery at 500 miles?

You're either doing something wrong while charging the battery or there is some ground issue with the bike.

The state of charge indication is a measurement of voltage, so it's no surprise that it drops off quickly at first.. Don't worry about that.

How do you charge the battery?
 

topcatken

Member
I think CptPalmer has hit on the problem/issue. I still seem to get distance despite the initial drop off. But when I wrote to Stromer they didn't act as if it was normal. My inquiry even asked might what I am observing be normal or not. As to my charging methods. I was directed by Stromer Customer Service to take the charger off after no more than an hour after the light turned green. My last bike was an E-moto and the company suggested leaving the battery charger on as long as I wanted because they said it would not overcharge. I charge the battery on the bike. I do not remove it.
 

JoePah

Well-Known Member
OK.. Do you turn off the bike power at the display on off switch before you connect the charger? Is the charger off before you connect it? You probably do but just checking.
 

topcatken

Member
The bike power is off. The charger I have does not have a switch. It connects to the bike, then the socket and it has one light which comes on with the fan. When charged the light turns constant green and I disconnect. Yes, it is a Stromer charger.
 

5thumbs

Member
No "new" information here.... I have 2 gold batteries. The initial battery is 2 years old and I have not seen a reduction in capacity. The newer battery is a few months old and the capacity is the same as the 1st. I cannot easily charge either of the batteries to 100%. It peaks out at about 92% and I can play tricks to get it to 100% (buy plugging in and out to top off), but as other's observed, it rapidly goes declines in capacity from 100% until it reaches about 85%. The discharge is not linear. Rapid drop from 100 to about 85% then slows and is stable to about 35%. I run out of juice when it drops below 10% (maybe 8%). I'm on my 2nd ST1 and the charging/discharge on both of the bikes seems the same. Same with the chargers (I have one with switch and one without). For awhile i had a problem with charging, but found it was due to the plug on the charger that goes into the wall socket was not getting a good connection (I was plugging into my shop light and the socket was not good).
 

Nebster

Member
One improvement Stromer can make in the future is for the BMS to better linearize the SOC readout. You and I shouldn't have to be consulting lithium discharge curves to understand how much energy we have left in our battery. The computer should do that work for us.

I was disappointed the first time I ran my battery to 10% and the bike shut down. I'm happy that the BMS shuts down to protect the expensive cells... I just don't want to have to think about it. If the bottom 10% is not usable, then just subtract it out and show me the usable percentage remaining. :mad:
 

Ravi Kempaiah

Well-Known Member
One improvement Stromer can make in the future is for the BMS to better linearize the SOC readout. You and I shouldn't have to be consulting lithium discharge curves to understand how much energy we have left in our battery. The computer should do that work for us.

I was disappointed the first time I ran my battery to 10% and the bike shut down. I'm happy that the BMS shuts down to protect the expensive cells... I just don't want to have to think about it. If the bottom 10% is not usable, then just subtract it out and show me the usable percentage remaining. :mad:
It has been done on ST2 already. Very linear SOC readout
I don't see much voltage sag compared to other bikes I have ridden or owned.
I have taken it down to 2% on several occasions and even the boost mode worked at 2-3% of battery.
Some of the other 36V bikes had appreciable voltage sag near the end of battery, not the ST2 in my experience.
 

Nebster

Member
That's excellent to hear. All the batteries "sag", so it sounds like they are managing the usable regime above the falloff. Good for them.