E-Bike Battery Guide

[TomD]

I'd think ebike companies would have significant liability exposure if risk was significant and they didn't give ample warning. Just for grins I went to the RAD site to find disclaimers. This is the best I can find:

Charge and store the bike and battery in a dry location, between 50 °F - 77 °F

Risk of injury from an accident is probably higher, not that I don't take precautions for that. As temps have plummeted here, I brought 3 batteries in from the garage and put them in the laundry room. While dry, probably not the best spot as it's one of the warmer rooms with more combustables. Not sure where else to put them.

 

[Ravi Kempaiah]

havent seen a single article on ebike battery fires.

Please read this latest Consumer Reports article below and this paragraph is straight from the article:

How to Prevent an Electric-Bike Fire - Consumer Reports

Consumer Reports shares advice from the FDNY on keeping the lithium-ion batteries on an e-bike from overheating to prevent an electric-bike fire.

www.consumerreports.org

"New York City has had a sharp increase in e-bike fires during the pandemic, so fire officials are offering some tips to keep the lithium-ion batteries on the bikes from overheating.
E-bike ownership has skyrocketed in New York since the pandemic began, and with it, e-bike fires, according to the New York City Fire Department (FDNY). There have been 75 e-bike fires so far this year, which is on pace to double last year’s total, officials said. The fires have caused 72 injuries and three deaths."

 

[George S.]

It’s very confusing. I remember looking at replacement batteries for my ebike in 2014. It was like $900 with the shipping. So I looked around and found the hobby lithium, Lithium Polymer. People said they were very unsafe. They didn’t have any BMS or anything like that, just balance leads. Still, I put some together, series and parallel, and used them for a couple of years. I hacked the connector on my ebike. The thing was, now I could use watt meters and watt hour meters, and I could put the packs wherever I wanted. From there I bought an LFP pack from China. Took forever. Pack is still going strong. I bought some hoverboard packs from one of the Big 2 recyclers, forget which. It worked great. People constantly said they are beyond dangerous, borderline insanity to even own. Never had a problem. I’ve bought the Liito Kala $100 packs with 21700 cells. Now they are on Ebay for double the price. After all the fear, all the endless lectures, I finally built two LFP packs from cells. They are supposed to be safe. I bring them in the house, leave them fully charged, taunt them, question their masculinity, dress them in little clown costumes. Just to test them.

What does a cell cost? What Chinese cell can I trust? There is a lot of stuff for $2 a cell. My LFP were $3 and they are 6 AH. The cost of the cells for something like a standard 4x13 pack is not very high. So, what do I do to make a great pack? Fuses? Fuses are good? Spacers? Seems like every pack I took apart was glued, but maybe that was old school. If I do X, Y, and Z, how safe is safe? I give up.

I bought a Lectric XP in November. OK, so they have sold 100,000 units. That’s a lot of battery packs. I don’t hear of problems, and there are forums. What does Lectric say? They say very little, just very basic stuff, nothing you would treat as a dire warning. A lot of it is marginal advice. You have to use their charger? Well, OK. But you don’t.

What is a battery pack supposed to cost? How is it supposed to be built? When will it fail, like riding or charging, or something else? I figure $200 should buy a pack in a wrap. Lectric sells replacements for $300 in a pretty nice metal case. I tested my XP pack. It’s what they say. It’s actually solid, but a little small.

If I owned an apartment building in NYC, I might not allow battery charging. But who are the people with the fires? Are they running delivery bikes that get used all day, and might be fast charged?

We know oil is safe. No refinery fires, oil spills, burning cars. Nothing like that.

How much should a standard ebike battery cost, anyway? We don’t make cells. Not really. The Chinese, Koreans, they make cells. The Chinese are not much fun to deal with, anymore. On a lot of levels, I don’t think the US ebike industry has thought this through, or thought about the next couple of years. Lith packs are a profit center. The stuff that works with lith batteries is just exploding. Well, so there really is an explosion, somewhere.

 

[AleksR]

I am in New York right now and many are riding these kind of eBikes

, for delivery purposes, with throttles and I am not sure what type of battery they are using, but appears to be a non standard modification of existing bikes. I suspect that these batteries are of poor quality which may explain these issue which I suspect are also unique to the New York landscape.

 

[AleksR]

Your facts. Not based in reality. The data is out there. But I guess we live in an age of alternative facts.

Where is the data?

 

[Ravi Kempaiah]

With rising cases of battery fire, it is imperative that people put emphasis on safety.
There has been some discussion about CE and UL certification. It is important that people look for UL or CSA certification in N.America.
CE label doesn't really mean much. Someone who is deeply involved in safety standards shared this with me.
---------------------------------------------------------------------------------------------
I get this question a lot from startups on where and how you get CE "certified". CE is short for Conformité Européenne(French for European Conformity). It's a sticker/symbol placed in your hardware product to let the user know that you are conforming to all directives by the European protection standards. So as a rule of thumb, if your product is marked "CE" you can freely sell your product in the European Union. This is NOT a certification mark. Please understand that.

So back to the question how do you get it? CE is a self-declaration process, meaning you as a manufacturer can put the CE logo on your product. Once it's placed on the product, it's assumed that you as a manufacturer have taken the effort to test all the relevant directives and have passed all quality and safety standards mentioned by the EU. The onus is on the manufacturer, they can slap a logo on the product and not have done any of that. Therein lies the problem of CE, where people think just because it's marked as CE means that the product is of the highest quality. Again, CE is not a Quality or Certification Mark.

In a proper workflow, if you need to affix the CE symbol on your hardware product, you need to create something known as a Technical file, which details all the product specifications, test safety reports, standards compliance reports, instructions of use, etc. This document is to be produced to EU authorities when asked for or when a dispute is raised. You can be penalized if your product doesn't adhere to some standards which you may have missed. Then there is a document called Declaration of Conformity which is an undertaking mentioning that your product adheres to a list of EU directives. This is to be signed by some person in your company taking ownership saying these standards are met.

When you do put the logo on your product, please make sure that you follow the CE Logo's standard design guidelines. There is a myth floating about that the China Export logo is a similar logo found on products shipped from China and you should look at the spacing to ascertain that it's an actual CE logo. Actually, a logo like that doesn't exist. I don't think it's hard for any manufacturer to adjust the spacing on symbols to fool you if they want. Just because you see CE in a product it doesn't mean anything. Always remember that.

 

[Dewey]

An MIT paper describing an aluminum-sulfur technology using a chloro-aluminate molten salt electrolyte, described in this PR piece as storing a few 10’s of kWh’s and tested at a fast cell charging rate of a second at an operating temperature of 110 degrees C.

Fast-charging aluminium–chalcogen batteries resistant to dendritic shorting​

 

[Ravi Kempaiah]

An MIT paper describing an aluminum-sulfur technology using a chloro-aluminate molten salt electrolyte, described in this PR piece as storing a few 10’s of kWh’s and tested at a fast cell charging rate of a second at an operating temperature of 110 degrees C.

Fast-charging aluminium–chalcogen batteries resistant to dendritic shorting​

Thanks for sharing this. One of the scientists on the team on that paper served on my Ph.D committee, and we are aware of this excellent piece of work. It would take sometime before it can be commercialized, but this is an excellent body of research that may open up new possibilities.

 

[tomjasz]

Thanks for sharing this article! It is very helpful for eBike users. If anyone is looking for the best e bikes to rent, then visit our website. We provide State-of-The-Art eBike Rental Services to witness unique landscapes, high-quality single trails, and an unlimited network of eBike trails in the Engadin and St. Moritz.

SPAMMER! Please read the rules.

 

[gioflowers]

It helps to have an accurate reading of the ah’s used for timing purposes and the most precise instrument for that is a CA 3, also made by Grin. $120 or so option, so cheaper than a Satistor, and makes the timer deal less of a guessing game. Not to mention it’s many other features.

A simple watt meter in the power line will do it cheapest though but If you take off the battery during a use cycle and plug it back in it zeros out the ah’s but still reads the correct voltage.

View attachment 23887

Was just there today actually

MB, ML320 - a great bargain if you can get one.

 

[Nomad]

if you use a charger that is made to balance your cells and is designed for your application and not just a universal charger along with a good quality battery it going to make a big difference.

 

[Downhiller]

Mike: Proprietary batteries require proprietary chargers. Giant Smart Charger is more than something you could use for DIY solutions. You certainly don't want a fire you could not extinguish. (Also, I would follow manufacturer's guidelines were I you).

I am so pleased to have the Giant Smart Charger. My LBS didn’t know its « charge to 60% » feature, or how it changes its charging after a certain number of cycles. I’m very happy not to have to use timers etc. i can just press a button & it will stop charging at 60%.

 

[Downhiller]

This thread is dedicated for helping new E-bike owners to understand and maintain their batteries in the best possible way.

There is a lot of confusion for any new E-bike owner as to how one should treat their batteries: Shop owners may say one thing, online resources may another thing, someone else says charge after every ride, dont worry! and few others say charge to 80%. It is painful to see so much misinformation floating around. So, you may ask why should I trust this information anymore than some random internet article. Nope, you don't have to trust me. The thread will have information that is thoroughly vetted by the scientific community and is widely accepted, not my personal opinion.

1. I just got a new E-bike, how should I treat my battery?
   
   Awesome! Your eBike comes with a battery charger and give it a good look and make sure it is the right one.
   A 36V bike should have a charger that goes upto 42V or
   a 48V bike should have a charger that goes upto 54V.
   
   Most ebikes are shipped with batteries at 50% charge. Before your first ride, your shop should have charged it to 100%. If you bought it online, plug in your charger and charge it all the way. Once the charger reaches the 100% mark, it should turn green from red.
   
   
   
2. What is the best practice for charging an E-bike battery?
   
   On your E-bike manual or your dealer who may not have the scientific background, may say, top it off after each ride. Yes and no. If you don't care about the longevity of the battery, just charge it after each ride, the high voltage cutoff (HVC) in the battery management system (BMS) shuts it off after it reaches 100% ( 42V for a 36V battery system or 54.5V for a 48V battery system). This practice may provide roughly 400-500 cycles before there is a substantial degradation in the cell chemistry. You simply don't have the mental bandwidth or interest in managing your battery and you are happy to replace the battery after 2 years, then you don't have to read any further.
   
   But, Li-ion batteries have infiltrated our lives (laptops, phones, tablets, cars). So, it can be good to know a bit more. Have you ever wondered why cellphone batteries or laptop batteries die quickly within a year or so. Plugging it in overnight is def one of the primary causes. Read on..
   
   What should I do?
   
   Charge your battery when it is not too cold or too hot. Let's say you just came back from a 50 mile ride and the battery is pretty warm ( you may not be able to feel it by touching the plastic case, but it does get warm). Leave it for 30 mins so it is back to the room temperature. Ideally, charge your batteries such that it does not sit fully charged for hours. So, if your morning commute starts at 7.30am, either charge your battery to 80% the night before or that early morning.
   
   You can double the cycle life of your battery by charging it only to 80%. Here is a neat infographic from Grin Tech in Canada, one of the innovators in the space.
   
   View attachment 23854
   
   They even developed a smart charger for this purpose called "Cycle Satiator". Check this out: http://www.ebikes.ca/product-info/cycle-satiator.html
   
   I don't have a Cycle Satiator nor do I want to invest in one!
   
   That's perfectly fine. You can just use the charger that came with your bike (most generic 2A chargers are made by Modiary or Shenzhen in China). Try to the keep the state of charge (SOC) between 20% to 80% if possible and enjoy your bike.
   
   There are other cheaper options out there that do a similar job.
   36V charger ----- 48V charger ---- 52V charger.
   
   If you are interested in maximizing battery life, be mindful of these two parameters:
   
   High temperature = BAD for Li-ion cells. So what is high temperature? Anything above 40'C or 105'F (trunk of a car on a hot summer day or exposing battery direct sunlight in Arizona or running your eBike on full turbo or throttle. One can run his E-bike on full turbo if the cell chemistry is tuned for that (Samsung 30Q vs 35E).
   
   Time (days or weeks) spent at high voltage = BAD for Li-ion cells. You charged it 100% and you're going away for a long weekend. This may not be a good idea.
   
   Everyone in the electric vehicle space knows who Elon Musk is, so I am attaching a pic of his response to this question.
   
   View attachment 23848
   
   
3. How to store your E-bike battery?
   
   It is best to store your battery at room temperature (cool, less humid conditions) and at 50% charge. If that's not possible, just avoid storing at 100%. I am attaching a scientific article on how calendar life ageing and conditions affect the degradation. Basically, What they are saying is degradation is minimal in the 30%-70% zone.
   
   "
   
   "
   
   The paper is attached below [Predicting battery degradation in EV's].
   
   
4. What are some of the things that can damage an E-bike (Li-ion) battery?
   
   What causes Li-ion cells to die?
   https://electrek.co/2018/05/04/are-you-killing-your-lithium-batteries/ (the comments section has some interesting responses).
   
   Time spent at high charge ~100% charge is bad i.e., if you leave your charger plugged in overnight, expect ~500 cycles instead of 800+ cycles. It's perfectly ok to charge your battery to 100% but keeping the batteries at 100% for days may not be a good idea.
   
   A fantastic video by Prof. Jeff Dahn replete with scientific insights regarding battery degradation is here. Prof Dahn is world's foremost expert when it comes to Li-ion batteries. He invented the NMC chemistry and is the current Canada research chair heading Tesla's exclusive battery research program with a university.
   
   
   
   
5. What kind of charger should I use?
   
   If possible, use chargers that charge at less than 8A (most chargers run at 2A or 4A, which are perfectly fine).
   As long as you charge your batteries at 0.5C or less, it is better.
   Now, what is C-rating?
   C stands for the name of the great scientist, Charles Coulomb and Coulomb is also an international SI unit for electrical charge.
   If you charge your battery completely in 1 hour or discharge completely in an hour, that is 1C charge-rate.
   As long as it takes more than 2 hrs to charge your battery from 0 to 100%, you're fine.
   
   Tesla can be charged to 80% in 40 minutes but the car has very complex thermal management systems for battery, power control unit and engine. Since E-bike batteries do not have such cooling, it is better to charge them at < 0.5C. If you charge at rates below 0.25C, there may not be significant advantages compared to 0.25C.
   
   So, if your battery is 14Ah in capacity, a charger that charges at 2A to 5A is perfectly fine.

If it adds any credibility, I have been an E-biker for over 6 years and have had various level of exposure into this. I am also pursuing my doctoral work on Li-ion batteries at the University of Illinois.

For those who are interested in understanding the whole EV battery cycle and general overview of certain best practices, they may find this video useful. We received very positive feedback from the EV community.

The thread will have only vetted, scientifically verified data on how to treat your battery. Feel free to add your thoughts and questions that might enhance one's understanding on the topic, feel free to subscribe but please refrain from posting unrelated stuff.

Thank you so much for this !

 

[Petropoliskhan]

Ravi, thank you for bringing some FACTS to this thread.

 

[Lin B]

If anyone is still reading this thread - I just bought a Luna charger with an 80% cutoff setting. Is it okay to leave it connected overnight if I set it at 80%? I am not great about remembering to go out to the garage and unplug
it (which is why I bought a charger with settings instead of my original one). So will it give me fewer cycles if I charge to 80% and then leave it plugged in until the morning? thx.

 

[tomjasz]

If anyone is still reading this thread - I just bought a Luna charger with an 80% cutoff setting. Is it okay to leave it connected overnight if I set it at 80%? I am not great about remembering to go out to the garage and unplug
it (which is why I bought a charger with settings instead of my original one). So will it give me fewer cycles if I charge to 80% and then leave it plugged in until the morning? thx.

NO! It's not OK to leave a battery charging unattended. If you must get a timer that will shut the charger down. They are cheap.
Luna is cavalier, more so than any other reseller.

 

[Lin B]

It is not in a house, it is outside in a garage, lol. What I want to know is whether the charger, when set at 80%, stops charging even if plugged in. I'm not asking about fire safety. I'm asking about
the effect on the battery. I'll unplug it just as often as I unplug my current charger, which means sometimes I will forget. I've had ebikes/batteries for many years and still haven't blown myself up.

 

[tomjasz]

If all is right with the charger, it does stop charging when it reaches your 80% setting.

But still not a good idea.

Add a timer and be certain the charger is shut down and not cycling.

 

[Ravi Kempaiah]

What is missing from the E-bike world is high-quality, automotive grade batteries built for 5+ years of heavy duty usage with minimal capacity fade.
We hope to contribute to the E-bike world by offering such batteries in the near future.
Wire bonding is the method Tesla, Lucid, Rivian etc. use in their batteries. A proper design with Wires + bus bars + advanced BMS offer a level of build quality that can handle high-G forces acting on E-bike batteries.

 

[fooferdoggie]

What is missing from the E-bike world is high-quality, automotive grade batteries built for 5+ years of heavy duty usage with minimal capacity fade.
We hope to contribute to the E-bike world by offering such batteries in the near future.
Wire bonding is the method Tesla, Lucid, Rivian etc. use in their batteries. A proper design with Wires + bus bars + advanced BMS offer a level of build quality that can handle high-G forces acting on E-bike batteries.

View attachment 154149

dont they also have water or fluid cooling too?