Optimal SoC for a bicycle battery

[Hans Allis]

Judging from all the advice here, a Tesla battery pack seems happiest when operated around 50% SoC. So you charge it to 70%, drive it down to 40%, etc.

I'm curious to learn how well this usage rhythm would apply to an electrical bike battery. For the Batavus Padova Easy (Dutch brand) with a lithium ion battery (unsure about the exact chemistry used), the official advice is to keep it connected to the charger as much as possible. My gut says this isn't particularly great for the battery.

What are your thoughts on this?

 

[wycolo]

Properly charging a Lion battery requires a microprocessor based charger which a. shows battery voltage accurately and b. automatically shuts off the charging voltage before any over charging begins. A decent one (for 1 or 2 cells) costs at least $20-US. Money well spent.
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[Science->Truth]

I also assume middle SoC is best for my bike lion batt. In addition, after reading a number of the technical research papers, I store the batt in the fridge when not in use. High temps are significant factor increasing degradation rates. (I live in FL).

 

[Canuck]

I have an EcoReco scooter and the manual says to keep it charging (and thus fully charged) when not in use too. So I emailed the company and pointed out that I have a Tesla and I am told that it's best not to charge to 100% since that degrades the battery faster. I also pointed out the research on this issue:

How to Prolong Lithium-based Batteries - Battery University

But I asked if perhaps the charger and battery management system didn't charge it to 100%. The reply I got was that it is best for the battery longevity not to keep it fully charged despite what the manual says. I bet that's the same for your electric bike since it's unlikely they would lock out the top of portion of the battery and sacrifice range for battery longevity since a key selling point for electric bikes is range. You should specifically ask them if they lock out the top portion. If not, and I am almost certain they do not, only charge to 100% when you need the extra range and do that right before riding. Then again, replacing electric bike batteries is relatively inexpensive compared to a Tesla battery so perhaps it's not an issue. I keep my scooter in the basement of the trunk (it fits perfect in there) and only use it when I need to get from a charger to hotel, etc. and I don't need the full range, and I want it to last, so it caused me concern keeping it in there with a 100% battery, plus it can also get hot in the summer and heat combined with a fully charged lithium ion battery is not a good combination.

 

[Science->Truth]

I agree. I charge fully only right b4 a ride. They probably tell folks to keep it on the charger to make sure it never is completely discharged. Bricked. Many use a bike only occasionally. Bricked batteries would generate warranty and other complaints. (Slightly) Faster degradation, not as much.

 

[Canuck]

Bricked batteries would generate warranty and other complaints. (Slightly) Faster degradation, not as much.

Yes, good point.