Charging after "each and every use"?

[Ben Martinez]

Just curious. Why does RPB tell us to charge the battery every time we use the bike? It would seem that if I'm down one bar on Monday after a ride, I ought to be able to rely on my four remaining bars to get me through Tuesday's zipping around to the supermarket, the Dairy Queen, the bear-baiting show in the north end of town. Please discuss. And thanks.

 

[emco5]

Current opinion from Grin Technologies and the techies at Endless Sphere says that a lithium battery is most healthy if kept between 80% full charge and 20% minimum charge. Recharging a battery to peak capacity after every ride and then not immediately using it is not a good thing. Some eBike manufacturers actually specify how much charge time is needed to reach 80%.

 

[Alex M]

Emco has nailed it.
RP - and most other manufacturers - write manuals for an "average" person. They want it to look simple, otherwise most people won't understand and when they don't understand they are afraid to buy.

Most people have to charge it after each and every ride because there is a good chance that it will drop below 80% after this ride, and below 80 is not good. The longer it sits with <80%, the more it is affected.

BUT... you also have to make sure that you only charge it to 80-90%, not to 100% (charging it to 100% is desirable once in a while, not every day). Another thing that makers don't tell you is that you need a programmable charger that can be set to 80-90-100%. The cheapest model is about $150, while the one included with a bike is about $30.

Reading bars on display is not accurate, 4 bars out of 5 don't necessarily mean 80%.

 

[ebikest]

Charge it to 100% if you are going to use it soon after (within a few days), if you're storing it long term do around 60%. If you really want to baby it, charge to 80% using Satiator charger or use a timer. Otherwise don't worry about it and enjoy you bike. Too many people get too anal about this and its not really that big of a deal. Batteries are only going to improve and even if your current battery lasts 3 years, you will almost certainly want something better with longer range by then anyway.

This will help you decide

 

[Alex M]

Darn Satiator costs like a new battery
Luna have a cheaper version, still programmable.
I don't see improvements in chemistry that would make batteries better. Not on commercial scale yet. Though they are getting bigger and cheaper per WH, as a result of increasing production volumes.

 

[Ben Martinez]

Current opinion from Grin Technologies and the techies at Endless Sphere says that a lithium battery is most healthy if kept between 80% full charge and 20% minimum charge. Recharging a battery to peak capacity after every ride and then not immediately using it is not a good thing. Some eBike manufacturers actually specify how much charge time is needed to reach 80%.

 

[Ben Martinez]

Great replies, all of them! Thank you all!

 

[mrgold35]

I haven't found how much longevity you get from the 80%-20% charge technique compared to doing the charge to 100% and ride under 20%? I'm expecting to get 2 1/2 to 3 years of normal use with 100% charging after a ride with minor drop in range over time. I avg about 2 trips/charges a day at 60-70 miles per week. I usually let the charge stay where it is at after a ride if the Rover is going to sit for more than a day or up to a few weeks and just charge before I ride.

I sometimes take last minute detours up to 20 miles extra on the way home when the weather is nice. I also had headwinds of 15-20 mph with gust +25 mph that left me with under 20% power on a 6 mile ride home (mostly up an incline on top of that). I rather take the hit on longevity compared to running out of power or having range anxiety on longer rides at 80% charge.

 

[jazz]

I haven't found how much longevity you get from the 80%-20% charge technique compared to doing the charge to 100% and ride under 20%? I'm expecting to get 2 1/2 to 3 years of normal use with 100% charging after a ride with minor drop in range over time. I avg about 2 trips/charges a day at 60-70 miles per week. I usually let the charge stay where it is at after a ride if the Rover is going to sit for more than a day or up to a few weeks and just charge before I ride.

I sometimes take last minute detours up to 20 miles extra on the way home when the weather is nice. I also had headwinds of 15-20 mph with gust +25 mph that left me with under 20% power on a 6 mile ride home (mostly up an incline on top of that). I rather take the hit on longevity compared to running out of power or having range anxiety on longer rides at 80% charge.

I think there is a lot of truth to this. I am rebuilding a lithium pack from a 2013 ebike that I always charged to 100%. Lasted a good 4.5 years. My other ebike pack still measures at full volts even after 3 solid years charging to 100%. I also have 2 electric motorcycles. One is a 2010 model with 3KW battery pack. Still measuring at almost at almost 90% capacity with 100% full charges for 7+ years. I have 2 friends with two Nissan Leafs. One is 2011, one is 2012. Most of the Leaf forums recommend 80% charge to maximize battery life. I believe even Nissan recommends this. One buddy followed this to the T. My other female friend did not. The 2012 80% Leaf is around 40K with 1 bar gone. The 2011 100% is closer to 50K with also 1 bar gone. The 1st bar = 15% loss in capacity.

The data on this is not conclusive despite what battery experts say in youtube videos, battery scientists and ebikers on every forums. There are a lot of variables to consider.

 

[RonDog1957]

I am really glad to see this post. With the battery about 1/3 the cost of the bike, it doesn't seem there is enough focus on good battery charging practices. I am on year #2 with my RadRover (800 total miles). Last year I used to plug in immediately after a ride and let it sit plugged in at full charge until next use. I now usually park the bike unplugged after a ride and then plug it in at an opportune moment to full charge before my next ride. So it mostly sits around a 50% charge when not being used but I am not anal about it. Maybe not quite optimal but as said above, isn't the purpose of the bike to enjoy it? Great comments by all.

 

[Denis Shelston]

Thank you all for your answers and suggestions. Very much appreciated.

As mentioned, it's the most expensive component of an E-bike, one has to take good care of it but not go nuts on this.

 

[Alex M]

2 schools of thought on batteries:
1) treating it as a disposable, max enjoyment, charge whenever it's convenient, or
2) trying get max life out of it.

Mrgold - there are no massive statistics on how keeping it at 20-80% improves the battery life. I tend to trust techies that have come to this conclusion. Overcharging Li batts isn't a good practice, automotive industry concluded the same. If you are worried about long rides with 80% charge, you might need a bigger battery. (Easy to say, I know). Range of ebike is so ridiculously short, they can get away with this because we are pedaling it more than motoring.

Manufacturers that specify "how much charge" you have to put in, to reach 80%, must be kidding. The amount of time needed to reach 80% depends on the amount of charge already there. Since there is no easy way to tell how much charge is in there, you don't know when to stop charging. At best, they would tell something like "If it's empty, charge it 5 hours with our charger for Full charge or 4 hours for 80%".

I've been thinking about this programmable charger: https://lunacycle.com/batteries/chargers/luna-charger-48v-advanced-300w-ebike-charger/
Don't know how exactly it does those 80-90-100 limits. Not sure that it "doubles" the battery life as they claim, there isn't enough statistical data to tell.
Satiator at +$300 cost is a questionable value because of the cost.

 

[Ravi Kempaiah]

One buddy followed this to the T. My other female friend did not.

Nissan has actually capped the SOC. Most electric cars don't use the full capacity of the battery .

Not sure that it "doubles" the battery life as they claim, there isn't enough statistical data to tell.
Satiator at +$300 cost is a questionable value because of the cost.

There are too many variables to just say charging to 90% would enhance the life. Unlike an electric car, ebikes battery can be taken out of the system and exposed to lot of different elements.
The ebike market is so new and everybody is doing their own thing. The low end market is filled with Dolphin packs, sharks, Rention packs. Other manufacturers use their own system.
In a few years, as the market matures, standardization will occur or else the companies won't be able to bring economies of scale.

 

[Alex M]

Nissan has actually capped the SOC. Most electric cars don't use the full capacity of the battery .

I've been suspecting this. A built-in circuit that limits the charge.

Form-factor is not an indicator of battery quality. High-end ebikes prefer proprietary shape because of looks - at that price the customer wants it to look nice, not just to work well, and doesn't care that his battery costs a few hundred bucks more.

 

[emco5]

I've been suspecting this. A built-in circuit that limits the charge.....

aka BMS

 

[Jean.Petr]

Really interested in this thread as I'm building my own battery pack. The one thing that I've read elsewhere that is important to battery life is 'cell balance'. A good accurate BMS would seem to be more important than the the exact charge %?
I've looked at the Satiator too but is expensive compared to adding $50 to the cost of your BMS for a better spec.? What's your thoughts on BMS versus charge cycle?
One guy that does know a bit about lithium battery life is Jeff Dahn, if you have an hour to spare (while waiting for your battery to charge!) this is a very informative video.

 

[Alex M]

aka BMS

BMS in Nissan must be different from ebike, or there are more control circuits in a car, in addition to BMS.

Those BMS that we have on ebikes, will not limit the charge cycle to 80 or 90%. It only has fixed limits for over-voltage and under-voltage, meant to prevent the battery from immediate destruction, and (usually, though not always) - limits of current used for charging and discharging. Plus, cell balancing job - very important.

Controller would have its own V/A limits as well.

 

[Alex M]

What's your thoughts on BMS versus charge cycle?

What's your thoughts on healthy leg muscles versus proper footwear, for hiking? You need both.