Charge cycles

[VirgilCaine]

I was looking at two fairly similar FS MTB bikes with the Brose motor and wonder why their charge cycles differ so much.
One lists 700 charge cycles for a 460 wh battery while the other is listing only 500 charge cycles for a 600 wh battery.

 

[rich c]

It's my take, that any number associated with a battery is some kind of guess. They have trouble with the definition of a charge cycle. Is it from BMS high and low shut off points? 20% to 80%? Then you throw in ambient temp variables, it's just a guess. If I understand it correctly, Bosch is one of a few that record the complete battery history in their software. Maybe they can give a better description based on data collected.

 

[Chris Hammond]

Its very hard to predict how one battery will hold up compared to another. Their are plenty of ??? quality batteries on the market. That said, taking care of the battery you have will lead to longer life. Follow a few simple rules, don't expose the battery to extreme hot or cold temps often, and never store it in them; charge the battery slowly; avoid full charge and discharge; charge the battery to 80% routinely, (some BMS require occasional 100% charge to balance the pack), and don't discharge below 20%. Other than that don't stress about the rest.

 

[VirgilCaine]

It's my take, that any number associated with a battery is some kind of guess. They have trouble with the definition of a charge cycle. Is it from BMS high and low shut off points? 20% to 80%?

So BMS has the 20/80 built into the system ?

 

[Leandro]

A charge cycle is typically completed with a full charge from 0-100%. Max and minimum temperatures, quick charges and discharges, stability and quality of the cells, etc. can all affect a battery's long term health.

 

[Bruce Arnold]

So BMS has the 20/80 built into the system ?

No, not unless there's an unusual BMS out there somewhere. There are chargers that can shut off at 80%.

 

[John from Connecticut]

No, not unless there's an unusual BMS out there somewhere. There are chargers that can shut off at 80%.

Hello, I 'get' the 20/80 rule as a means to extend the battery life, but if a rider faithfully adheres to the rule, they ( we )
are giving up 40% of the available stored power ( and riding time ) to extend the battery life by ?? If I follow the 20/80
logic we'll need to get some extended battery life exceeding the 40% we gave up, never mind the shorten ride time to
'play be the rules'.

I'm missing how the 20/80 rule benefits us in the long run from a convenience stand point. ? Can someone help me out
on this ? Thanks.

John from CT

 

[Ravi Kempaiah]

I'm missing how the 20/80 rule benefits us in the long run

Obviously you are missing the point, John.
See this link and the image below.

When you charge your battery to 80%, you can get 1500 cycles instead of 500 cycles.

Now, you DON'T have to but some people prefer to. Chevy Volt has 18KW pack but it only uses 12-13KW out of it. The battery guaranteed for 8 years or 100,000 miles.

How many E-bike companies offer 8 year warranty on a battery pack?

 

[John from Connecticut]

Obviously you are missing the point, John.
See this link and the image below.


When you charge your battery to 80%, you can get 1500 cycles instead of 500 cycles.

Now, you DON'T have to but some people prefer to. Chevy Volt has 18KW pack but it only uses 12-13KW out of it. The battery guaranteed for 8 years or 100,000 miles.

How many E-bike companies offer 8 year warranty on a battery pack?

Obviously you are missing the point, John.
See this link and the image below.

When you charge your battery to 80%, you can get 1500 cycles instead of 500 cycles.

Now, you DON'T have to but some people prefer to. Chevy Volt has 18KW pack but it only uses 12-13KW out of it. The battery guaranteed for 8 years or 100,000 miles.

How many E-bike companies offer 8 year warranty on a battery pack?

 

[John from Connecticut]

Hello Ravi,
Thank you very much for your reply, complete with the great battery cycle life chart. I really appreciate it. I had no idea the 20/80 rule was so significant in determining the battery charge cycle life.

For the style of riding I normally do I think the 20/80 rule may work, I'm going to try it for time and distance. I hope it does because 1500 recharge cycles is fantastic. My comment was more academic and for a rider that needs max power.

Thanks again,
John from CT