Am I missing something?

Corey

New Member
First I want to thank everyone who contributes to this forum. Your experience and candid conversations are a big help to anyone (like me) starting this e-bike journey. I am looking to move my current commute of 28 miles (RT) from my normal road/MTB to an e-bike. As I go through the testing of drive systems and geometries the one thing I keep looking at is batteries.

I know the calculations for range (sort of) and power, but the warranties for charge cycles seems all over the place. I have determined that this early adopter phase will not be cheap, but it seems the one primary disposable item is the battery and from what little I've read they are expensive, especially at higher capacities.

I noticed that both Specialized and Stromer offer battery warranties, but vastly different. Something like 300 charge cycles vs 1000. Assuming I commute 280 days, I would need a new battery on the Specialized in a year, two years max, considering the charge cycles? The Stromer 1,000 charge cycles might be 3 years, in which time the technology will be upgraded/different so I may need to change anyway, but I saved on a replacement battery during that time.

Just wondering more than anything how much you all worry about total battery life and any warranty, or am I starting to nit pick on the small things instead of the bike itself. I used these two examples since they are similar power rear hub drive bikes. Any light you can shed is helpful as the LBS seems a little vague on how warranties are handled.

Thanks, Corey
 
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Doker44

New Member
F.
or am I starting to nit pick on the small things instead of the bike itself.

IMO the battery is as important as the bike and system itself. Its not a small thing, without the proper battery no matter what bike and system you choose it will not perform. As far as different cycles you mentioned thats a monster difference, you need to research that more.If those were the two bikes I was looking at I would call them and see how a warranty worked. 300 cycles doesnt seem like much of a warranty to me!

Personally if I was on a budget I would choose a bit of a lesser bike to get the best battery.

Doker44
 

JoePah

Well-Known Member
Here's the deal. Both Specialized and Stromer will use high quality japanese battery cells, quality BMS and come with a quality, fan cooled charger.

So if you're really going to use your eBike 5x a week, buy an ebike with a battery capacity that will take you more than twice as far as you need to go every day. Don't charge the battery to 100%, only 90% or so, and don't discharge it below 30%, if you can help it. And when the batter starts losing capacity, the larger battery will still be enough to get you around.

There are many capacity curves vs charge cycles out there and they all point to the same thing.. Lower the discharge per cycle, and your battery will last many more cycles. Electric Car manufacturer's can offer 8 or 10 year warranties because their cars are desiged to utilize a narrow range of battery capacity.

The Stromer ST1 Platinum has a larger battery pack, like 500wh. By adjust the amount of pedal assist, you should be able to keep your battery usage under 50% for your commute. And you should get closer to 1000 cycles.
 
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Brambor

Well-Known Member
I'm on closing in on the end of my second year with Specialized battery and the bike is still going strong. I haven't really seen any noticeable drop in charge. At any rate, they now have even larger battery and I have contemplated just buying it anyway. With the amount of my commuting miles the bike paid for itself after 1 year so I have nothing to gripe about.
 

George S.

Well-Known Member
For simplicity, you want a charger that can be set for 80% or 90%, as well as 100%. I bought one of these from Luna Cycle. Justin at Grin has the Satiator. Paul at EM3ev has several chargers with an end charge set switch.

If you add 10% to the capacity of the battery (as the unused 10%), and use a 90% charge, you double the life. That's what Tesla and other auto makers say. How much could that cost?

(The red switch toggles to 3 end charge states, 80,90, and 100%)
luna charger.JPG
 
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EddieJ

Well-Known Member
Just wondering more than anything how much you all worry about total battery life and any warranty.

Other than not storing the battery in a cold place, I don't worry at all. I'd rather be out enjoying full use of the bike. E-bikes don't have enough battery range as it is, without creating self imposed reduction of range as well.

As recommended in both the Bosch and Panasonic manual, I charge the battery to 100% and just let the electronic cell protection (ECP) do it's job. I also often return home with between 2-5 miles remaining. Again, I'd rather get maximum mileage and usage out the bike and let the ECP do it's job. That is what is there for.

The only time that I wouldn't charge to 100% is if I was going to be storing the battery for say a three month period. In that case, I would just charge to three bars/ 60% capacity.
 
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opimax

Well-Known Member
I am w/Eddie. i use my 2 batteries up pretty much each outing. this "hobby" is the only thing that takes nonessential money , i deserve it! If i need a new battery after i quit crying i buy it :)

If I know I dont have time to use them both I dont drain them as much and do drain them as evenly as I can guestimate.
 

Corey

New Member
I want to thank you all for taking the time to respond to my question. I now understand that I need to stop typing and just get a bike and move on, batteries are just one aspect. I really like the charger technology, so I've learned something new right away. I look forward to sharing anything I can, and I am excited not for only the new ride, but what the next generation of bikes bring.

Cheers and Thanks, Corey
 

Jack Tyler

Active Member
Corey, like you I'm using this forum to help me learn more about ebikes before making a purchase decision, but I do have a fair bit of experience relying on battery performance. The warranty differences you mention lump a variety of variables into one number so my belief is that you are looking at apples & oranges. First is what the bike mfgr. is willing to warranty, and that's purely a business decision based on assumptions they make (about customers, kind of bike use, # of units sold, etc.) Each company will come by their own decision based on their unique set of assumptions. Then there's the battery mfgr., which is where the ebike mfgr. is getting the battery performance data which in turn they fold into their warranty decision. Battery 'performance' is about capacity, the number of amps (usually measured in so many amps for so many hours, or amp/hrs) a given battery can provide at a given voltage. Spec a higher amp load on the battery when testing its capacity and it will correspondingly produce those amps for a lower period of time. BUT it's not a linear relationship. So a battery mfgr. may do a series of capacity tests at a relatively low amp draw and produce a very high amp/hr capacity rating whereas another might test a similar set of cells & battery chemistry but test to a higher amp pull that results in a lower amp/hr rating. (They may choose different amp loads for their tests because their main customer groups are different and so typical amp loads will be different). The ratings will be different only because the test parameters weren't the same.

Another key variable is what assumption is made about the typical % discharge a battery bank sees. A common practice is to spec a battery bank such that its normal amp/hr use in-between charge cycles is only 50% of the battery bank's total capacity. And one last data point: A battery's amp/hr rating isn't just 'X amp/hrs for Y cycles' but rather how many cycles the battery can supply some percentage of X amp/hrs. IOW with every cycle of use from Day 1 the battery's available capacity diminishes slightly. So mfgrs. have to pick an arbitrary percentage below 100% and measure the number of cycles that can still produce that percentage of the battery's original total capacity. The percentage I've seen most often is 80%

This last point intersects with JoePah's comment above altho' he's coming at it a bit differently. He's saying buy a bigger bank than you initially need and then, as the bank's capacity reduces with use, you'll still have enough to use the bank for a further period. Yes, that's one way to insure a given bank will serve for a longer period of time...but the bigger bank will cost more, so it's not necessarily a more affordable option. Instead, consider how to reduce the amount of capacity you consume: If your daily commute is 28 miles RT and you buy a bike that offers, for your conditions and % power used, ~35 miles of endurance before the battery gives up, then every day you'll be consuming ~80% of the battery's available capacity (assuming a full charge). That's a high drawdown and will result in many fewer total cycles of battery performance than could be available. But imagine riding only half that distance (14 miles) and then charging the bike before returning home. Now you have two trips, each one drawing down the bank by ~40%. You'll use the same amp/hrs of capacity, but you'll be much kinder to the bank and thereby increase the number of cycles available.

Sorry about the length. People who go off the grid end up talking too much about batteries!
 

opimax

Well-Known Member
note Stromer's warranty for 3 years is 60% charge...pretty sure that is it. Would you be happy w/60% charge (max) when you use it ? A little more than 1/2 the distance available from new state. Last night did 70 w/2 batteries going hard, wouldn't be able to do that at 60% on 2 batterries but the warranty is still good. I cant complain because they have set my expectations. In the past my Stromer batteries have done much better than this so I am hoping it continues but realize what you are getting