battery life: better to not fully charge?

[George S.]

I don't know why the 90% charge setting is not on every ebike charger. It's completely painless to add to the circuit. Beyond doing that, it's more trouble than it is worth, for most people.

If you look at this:

http://www.greencarreports.com/news...m-lowest-battery-costs-of-any-maker-jefferies

It's clear battery prices will drop. So, in two years, most people will be better off with a new battery, or at least be able to afford one.

 

[MLB]

Nonsense, drain your batteries at will and charge till the charger says fully charged. I've been doing this for years with cell phones and even leave my Note phone charging overnight. I have never had a problem with deficiency save the normal degradation that occurs over time with many cycles. My guess is that any name brand bike with a lithium ion battery and a charger will have failsafe system built into the controller and charger that prevents premature damage to the battery. I have talked to the folks who make lithium ion batteries in Japan (Samsung and Panasonic) and neither of them brought up any charging/decharging issues or restrictions.

Right, cuz those MANUFACTURERS of batteries have so much incentive to reveal to you how to prolong (keep you from buying more) their batteries life.............
Not sure how learning MORE about the batteries we all use is nonsense, but whatever.........
I've read that you won't get the 1,000 charges or whatever number is bandied about if you discharge fully and recharge to 100%, but that you MAY get many MORE than 1,000 if stay at the 20-80% levels recommended.
If you read what happens to batteries at both extremes of discharge and charging, it really seems straight forwardly logical.

 

[dimitri brooks]

One thing to note is a lot of BMS only balance batteries at 100% charge. If you only charge to 80% the BMS might not do the balancing and this will degrade the pack.
https://en.wikipedia.org/wiki/Battery_balancing

 

[Deleted member 803]

Right, cuz those MANUFACTURERS of batteries have so much incentive to reveal to you how to prolong (keep you from buying more) their batteries life.............
Not sure how learning MORE about the batteries we all use is nonsense, but whatever.........
I've read that you won't get the 1,000 charges or whatever number is bandied about if you discharge fully and recharge to 100%, but that you MAY get many MORE than 1,000 if stay at the 20-80% levels recommended.
If you read what happens to batteries at both extremes of discharge and charging, it really seems straight forwardly logical.

I agree that all manufacturers are evil. I also agree that managing battery life is an important life goal and that if more of us paid attention to running out to the garage to pull the plug on the charger at an 80% charge the world would be a better place. You know, I stop every 3 minutes on my ride to check tire inflation and can't tell you the immense pleasure it gives me knowing that I will probably get an extra 3 miles of tire life by doing so.

I've calculated a spreadsheet that correlates circadian cycles with the phases of the moon and the length of vespers at my local church to determine the optimum time to ride my bicycle. The other thing that helps my piece of mind and my pocket book is to remove my chain after every ride and place it under my electron microscope to determine the grit level in the chain lubrication and how that might affect chain life.

 

[Pastabatman]

On @JoePah 's suggestion, I bought a couple of $4 electrical timers at Home Depot (1 for home, 1 for work) and preset them to keep battery under 90%. I just plug in, turn clock to start charging, forget about it. Once a week I charge to 100%, just in case my BMS isn't balancing otherwise.

Seems like a tiny effort to perhaps double battery life. Saves me money and amortizes environmental impact of battery manufacturing & recycling.

 

[PowerMe]

I charge mine to full from wherever it starts, be it down to 10% or 20% or 50%. I plug it in, come back hours later, light is green. Unplug. Done.

 

[Va. Bch. Electric Bike Center]

My best life span on an ebike Lithium battery is 6-7 years. Always charge it to 100%. I think this might be over thought concerning quality batteries with good BMS. Cheap junk batteries with minimal or no BMS however..

 

[Margo Allen]

If only...

Easy Motion batteries for the EVO line run in the neighborhood of $700+ MSRP.

No kidding! My Lifepo4 48v 20ah was $440 shipped, with a neat case with voltage readout. I consider that a bargain.
I wouldn't mind a more technical discussion regarding battery management, with considerations such as temperature affecting discharge and charging and overall life.

 

[Margo Allen]

Right, cuz those MANUFACTURERS of batteries have so much incentive to reveal to you how to prolong (keep you from buying more) their batteries life.............
Not sure how learning MORE about the batteries we all use is nonsense, but whatever.........
I've read that you won't get the 1,000 charges or whatever number is bandied about if you discharge fully and recharge to 100%, but that you MAY get many MORE than 1,000 if stay at the 20-80% levels recommended.
If you read what happens to batteries at both extremes of discharge and charging, it really seems straight forwardly logical.

That has no logic. Overall operating hours is the real indicator of life, not how many charge cycles! Of course you will have more charge cycles if you use it less each cycle!
I would rather not obsess over each charge, that is the job of the device, unless it is low tech. I agree that fully discharging the battery will stress it though.

 

[andybellnow]

Interesting discussion...

Forgive me if someone has posted this before but it comes directly from Stromer:

BATTERY
The ST1 is equipped with a high-capacity lithium-ion battery. This supplies energy to the drive system and all the other electronic components.

• Each battery has 50 Samsung battery cells.
• The battery management system (BMS) developed by Stromer provides overvoltage and undervoltage protection and optimizes the service life of the lithium-ion battery.
• You can simply use your ST1 battery in another Stromer ST1 or use an extra battery for your ST1.
• You can fully recharge the ST1 battery after every journey. This increases the service life of the battery and ensures that you are always prepared for the next ride. There is no need for you to run down the battery every time - there is no memory effect. Top up your battery charge as often as possible, do not let it run down to empty and recharge it even if it has only been in use for a short period of time.

Seems to contradict all of the information about charging only to 80-90%.

 

[Pastabatman]

Seems to contradict all of the information about charging only to 80-90%.

For the most part, Stromer is simply stressing to the user that these batteries do not have memory issues, and can be harmed by deep discharge (all true). It doesn't surprise me at all that Stromer and other manufacturer don't mention the benefits of under-charging, since it's a bit too fiddly for most consumers to worry about (see evidence of this mindset in this very thread) and the fact that it does nothing for the bottomline (and may even hurt it). The 'service life optimization' algorithms are almost certainly optimized for maximum (not average) range.

 

[andybellnow]

Those are good points. My question then is there anyone we can speak with at our manufacturer of choice who really knows what they are talking about with respect to the batteries and the BMS? Or would one have to speak to a tech at Samsung to hear it "from the horse's mouth" so to speak?

 

[Ravi Kempaiah]

Those are good points. My question then is there anyone we can speak with at our manufacturer of choice who really knows what they are talking about with respect to the batteries and the BMS? Or would one have to speak to a tech at Samsung to hear it "from the horse's mouth" so to speak?

If you have a 500Whr battery and only plan to use 80%, that would be just 400Whr. Given the demand for bigger batteries/ range AND light weight, most manufacturers would be reluctant to do such a modification.
However, as you suggested, you could speak to battery manufacturers and ask them how they designed the BMS. My hunch is that they won't consider 90% charge logic while designing these packs.