Charging fire safety e bikes

Electrically assisted bikes, trikes, etc. that are legal in the UK
axel_knutt
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Re: Charging fire safety e bikes

Post by axel_knutt »

Pinhead wrote: 9 Mar 2024, 1:07pm Speak for yourself !!!!
I was speaking for the manufacturers, who aren't going to make a special lamp just because the Brits want something different. We're only 1% of the market, they don't care what we want.

When I bought my unapproved Cateye EL320 lamp (in 2006) I rejected the only approved lamp available, the EL300, because it was obsolescent, and inferior in almost every respect.
“I'm not upset that you lied to me, I'm upset that from now on I can't believe you.”
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Cowsham
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Re: Charging fire safety e bikes

Post by Cowsham »

Here's that knowledgeable young chap again giving a comprehensive presentation on what causes ebike fires.


He gave one on regenerative braking once before where he shows an impressive knowledge of electro - mechanical stuff ( I've posted here before somewhere )

I thought he was bang on the money with this one.

https://youtu.be/j92Gt4VviSQ?feature=shared
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Jdsk
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Re: Charging fire safety eBikes

Post by Jdsk »

Jdsk wrote: 9 Mar 2024, 11:00am
PH wrote: 14 Sep 2023, 6:04pm This published a couple of days ago might be of interest:
The Office for Product Safety and Standards (OPSS) has today published information for consumers to raise awareness around the safe purchasing, use and charging of e-bikes and e-scooters.
https://www.gov.uk/government/news/opss ... ion%20kits.
It's getting attention today:
https://twitter.com/OfficeforSandS/stat ... 9946391695

Guardian coverage:
https://www.theguardian.com/news/2024/m ... bike-fires

Is there a new report or new guidance?
And a warning in the USA on the same U004/U004-1 battery pack:
https://www.cpsc.gov/Newsroom/News-Rele ... -and-Death

Jonathan

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Jdsk
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Re: Charging fire safety e bikes

Post by Jdsk »

From another thread:
The main problem are not the BMS or the battery case. The problem are cheap lithium cells from dubious sources.
Are there any data to support this? Or any other theory of causes?

Jonathan
Marc
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Re: Charging fire safety eBikes

Post by Marc »

Jdsk wrote: 21 Apr 2024, 12:35pm
Jdsk wrote: 9 Mar 2024, 11:00am
PH wrote: 14 Sep 2023, 6:04pm This published a couple of days ago might be of interest:

https://www.gov.uk/government/news/opss ... ion%20kits.
It's getting attention today:
https://twitter.com/OfficeforSandS/stat ... 9946391695

Guardian coverage:
https://www.theguardian.com/news/2024/m ... bike-fires

Is there a new report or new guidance?
And a warning in the USA on the same U004/U004-1 battery pack:
https://www.cpsc.gov/Newsroom/News-Rele ... -and-Death

Jonathan

Image
Here is the thread:
viewtopic.php?p=1840062#p1840062
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Marc
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Re: Charging fire safety e bikes

Post by Marc »

Jdsk wrote: 22 Apr 2024, 9:17am From another thread:
The main problem are not the BMS or the battery case. The problem are cheap lithium cells from dubious sources.
Are there any data to support this? Or any other theory of causes?

Jonathan
He talks about what battery cell model he found in his surviving Unit Pack Power (UPP) e-bike battery at around 1 min into the video:

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Jdsk
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Re: Charging fire safety e bikes

Post by Jdsk »

I watched the first minute.

Please could you summarise the nature of the evidence... is it all his personal experience and opinion about one make of battery?

Thanks

Jonathan
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Re: Charging fire safety e bikes

Post by Marc »

Jdsk wrote: 22 Apr 2024, 9:47am I watched the first minute.

Please could you summarise the nature of the evidence...
I rather not.
Jdsk wrote: 22 Apr 2024, 9:47am is it all his personal experience and opinion about one make of battery?
Its one data point, but its from the same crappy ebike battery manufacturer.

If you'd watch more than a minute, he also points out:
-while he explicitly ordered and payed Unit Pack Power for a particular model of genuine high quality cells, they used off brand cells
-threatened him with legal action, when he called them out on their fraud
Last edited by Marc on 22 Apr 2024, 10:12am, edited 1 time in total.
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Jdsk
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Re: Charging fire safety e bikes

Post by Jdsk »

Thankyou

Jonathan
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Re: Charging fire safety e bikes

Post by Marc »

I've just started to read this thread and there are some... "less informed" opinions here in the postings. Also, I often read equally "less informed" tips about Lithium batteries in the ebike media over the last dozen years, or so. Journalists, as well as sales people, most often are not the best source of technical info's and facts. More often than not, they simply don't have the time to gain the expertise and get their facts straight.

Here are some tips about Lithium batteries in ebikes, escooters, mobile phones, laptops, etc:
  • 1. Never, ever, charge Lithium batteries at temperatures under 0°C! Charging a "frozen" Lithium battery can induce the grow of crystalline "spikes" (dendrites) inside the battery. These dendrites will reduce the capacity of the battery and can cause an internal short and may even cause a battery fire. Take the battery inside and let it sit for a while, so the battery warms-up to room temperature, before charging.
  • 2. Don't charge Lithium batteries at temperatures under 5°C. The battery cells should at least have an internal temperature of about 10°C when charging. Best practise is charging a Lithium battery at room temperature (around 20°C)
  • 4. Don't use ebike batteries that had suffered an impact. If you drop your battery, or it was involved in an accident, you can't be sure it didn't suffer some structural damage.
  • 5. If you want to prolong the service life of your Lithium battery*, don't charge it regularly to 100% and don't discharge it regularly till its empty. Best practise is charging it regularly only to 90% capacity (roughly doubles service life) and don't discharge it regularly under 20-30% (thats an other doubling of service life!). Note the word "regularly". Its no problem if you charge your battery once in a while to 100% (see next paragraph), or discharge it till your electric assist system shuts down.
  • 6. Once in a while, you should fully charge your ebike battery and let it sit for an hour or two with the charger attracted. If you use your ebike every day on your commute, charging to 100% about once a month is enough. Background: A lot of BMS (battery management systems) out there only balance the battery cells of your ebike battery when the battery is charged to 100%. To stay on the safe side, the BMS should be able to do its job of balancing the battery cells once in a while.
  • 7. last but not least: Don't buy cheap Lithium batteries from Amazon, Ebay, Alibaba, AliExpress and the like. Cheap Chinese off-brand lithium cells can set your house on fire. If you build a DIY-ebike, get a quality battery with genuine brand battery cells from Samsung, Sony, LG, or Panasonic. You can't go wrong with batterie cells from these "big four". Top quality ebike batteries are available from ebikes.ca and em3ev.com for instance. They are about as "gold standard" as it gets regarding ebike batteries.

    If you want to learn more about Lithium batteries, or rechargeable batteries in general, take a look at the articles at:
    https://batteryuniversity.com


    *the only exception are LiFePO4 or LFP batteries: https://en.wikipedia.org/wiki/Lithium_i ... te_battery
    LFP batteries don't get noticeably longer service life by not charging them regularly from 0-100%. LFP have a typical service life of 2000-4000 charge cycles, usually don't burn and became the "lithium battery of choice" of almost every electric car manufacturers in the last couple of years.Their only downsides are lower cell voltage and about half the energy density of the other Lithium battery flavours = bigger and heavier battery
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Jdsk
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Re: Charging fire safety e bikes

Post by Jdsk »

Marc wrote: 23 Apr 2024, 6:54am ... Here are some tips about Lithium batteries in ebikes, escooters, mobile phones, laptops, etc:
...
Why did you embolden mobile phones rather than eBikes or eScooters?

Thanks

Jonathan
Last edited by Jdsk on 23 Apr 2024, 10:58am, edited 1 time in total.
Marc
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Re: Charging fire safety e bikes

Post by Marc »

Jdsk wrote: 23 Apr 2024, 10:05am
Marc wrote: 23 Apr 2024, 6:54am ... Here are some tips about Lithium batteries in ebikes, escooters, mobile phones, laptops, etc:
...
Why did you embolden mobile phones rather than Ebikes or eScooters?
How often did somebody tell you in the last 20 odd years, that you should never charge an "ice cold" mobile phone, or any Lithium battery for that matter?

I should have listed power tools as well, since they became available with Lithium batteries a 1-3 years before the ebike boom. The exact same Lithium cell models that make power tools so power full, where used (and are still used) in ebike batteries.

Personally, I never heard about it till I delved more into the subject and much later worked for the main importer of professional IZUMI power tools in Germany (repairing and servicing power tools, as well as testing customer batteries on a computerised battery test bench)
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Jdsk
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Re: Charging fire safety e bikes

Post by Jdsk »

Marc wrote: 23 Apr 2024, 10:53am
Jdsk wrote: 23 Apr 2024, 10:05am
Marc wrote: 23 Apr 2024, 6:54am ... Here are some tips about Lithium batteries in ebikes, escooters, mobile phones, laptops, etc:
...
Why did you embolden mobile phones rather than Ebikes or eScooters?
How often did somebody tell you in the last 20 odd years, that you should never charge an "ice cold" mobile phone, or any Lithium battery for that matter?

I should have listed power tools as well, since they became available with Lithium batteries a 1-3 years before the ebike boom. The exact same Lithium cell models that make power tools so power full, where used (and are still used) in ebike batteries.

Personally, I never heard about it till I delved more into the subject and much later worked for the main importer of professional IZUMI power tools in Germany (repairing and servicing power tools, as well as testing customer batteries on a computerised battery test bench)
Thanks. But that's not what I asked.

Jonathan
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Cowsham
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Re: Charging fire safety e bikes

Post by Cowsham »

Marc wrote: 23 Apr 2024, 6:54am I've just started to read this thread and there are some... "less informed" opinions here in the postings. Also, I often read equally "less informed" tips about Lithium batteries in the ebike media over the last dozen years, or so. Journalists, as well as sales people, most often are not the best source of technical info's and facts. More often than not, they simply don't have the time to gain the expertise and get their facts straight.

Here are some tips about Lithium batteries in ebikes, escooters, mobile phones, laptops, etc:
  • 1. Never, ever, charge Lithium batteries at temperatures under 0°C! Charging a "frozen" Lithium battery can induce the grow of crystalline "spikes" (dendrites) inside the battery. These dendrites will reduce the capacity of the battery and can cause an internal short and may even cause a battery fire. Take the battery inside and let it sit for a while, so the battery warms-up to room temperature, before charging.
  • 2. Don't charge Lithium batteries at temperatures under 5°C. The battery cells should at least have an internal temperature of about 10°C when charging. Best practise is charging a Lithium battery at room temperature (around 20°C)
  • 4. Don't use ebike batteries that had suffered an impact. If you drop your battery, or it was involved in an accident, you can't be sure it didn't suffer some structural damage.
  • 5. If you want to prolong the service life of your Lithium battery*, don't charge it regularly to 100% and don't discharge it regularly till its empty. Best practise is charging it regularly only to 90% capacity (roughly doubles service life) and don't discharge it regularly under 20-30% (thats an other doubling of service life!). Note the word "regularly". Its no problem if you charge your battery once in a while to 100% (see next paragraph), or discharge it till your electric assist system shuts down.
  • 6. Once in a while, you should fully charge your ebike battery and let it sit for an hour or two with the charger attracted. If you use your ebike every day on your commute, charging to 100% about once a month is enough. Background: A lot of BMS (battery management systems) out there only balance the battery cells of your ebike battery when the battery is charged to 100%. To stay on the safe side, the BMS should be able to do its job of balancing the battery cells once in a while.
  • 7. last but not least: Don't buy cheap Lithium batteries from Amazon, Ebay, Alibaba, AliExpress and the like. Cheap Chinese off-brand lithium cells can set your house on fire. If you build a DIY-ebike, get a quality battery with genuine brand battery cells from Samsung, Sony, LG, or Panasonic. You can't go wrong with batterie cells from these "big four". Top quality ebike batteries are available from ebikes.ca and em3ev.com for instance. They are about as "gold standard" as it gets regarding ebike batteries.

    If you want to learn more about Lithium batteries, or rechargeable batteries in general, take a look at the articles at:
    https://batteryuniversity.com


    *the only exception are LiFePO4 or LFP batteries: https://en.wikipedia.org/wiki/Lithium_i ... te_battery
    LFP batteries don't get noticeably longer service life by not charging them regularly from 0-100%. LFP have a typical service life of 2000-4000 charge cycles, usually don't burn and became the "lithium battery of choice" of almost every electric car manufacturers in the last couple of years.Their only downsides are lower cell voltage and about half the energy density of the other Lithium battery flavours = bigger and heavier battery
I agree with everything except part of point 5 " don't charge regularly to 100% "

what is the evidence or the mechanism by which a lithium battery is damaged by doing this?

( I understand why it's very important not to discharge it below 20% not just for battery longevity but also battery safety )
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Marc
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Re: Charging fire safety e bikes

Post by Marc »

Cowsham wrote: 23 Apr 2024, 11:56am
Marc wrote: 23 Apr 2024, 6:54am
  • 5. If you want to prolong the service life of your Lithium battery*, don't charge it regularly to 100% and don't discharge it regularly till its empty. Best practise is charging it regularly only to 90% capacity (roughly doubles service life) and don't discharge it regularly under 20-30% (thats an other doubling of service life!). Note the word "regularly". Its no problem if you charge your battery once in a while to 100% (see next paragraph), or discharge it till your electric assist system shuts down.
If you want to learn more about Lithium batteries, or rechargeable batteries in general, take a look at the articles at:
https://batteryuniversity.com
I agree with everything except part of point 5 " don't charge regularly to 100% "

what is the evidence or the mechanism by which a lithium battery is damaged by doing this?

( I understand why it's very important not to discharge it below 20% not just for battery longevity but also battery safety )
Lithium batteries degrade faster (eg loose capacity) due to chemical processes inside the battery:
  • with time (calendar life)
  • at higher temperatures
  • at higher voltages for a prolonged time

    From this article:
    https://batteryuniversity.com/article/b ... -batteries
    Every 0.10V drop below 4.20V/cell doubles the cycle but holds less capacity. Raising the voltage above 4.20V/cell would shorten the life. The readings reflect regular Li-ion charging to 4.20V/cell.

    Every 70mV drop in charge voltage lowers the usable capacity by about 10%.
    For safety reasons, many lithium-ions cannot exceed 4.20V/cell. (Some NMC are the exception.) While a higher voltage boosts capacity, exceeding the voltage shortens service life and compromises safety. Figure 5 demonstrates cycle count as a function of charge voltage. At 4.35V, the cycle count of a regular Li-ion is cut in half.
    Image
    the image doesn't load. go to https://batteryuniversity.com/img/content/lithium2.jpg
    Besides selecting the best-suited voltage thresholds for a given application, a regular Li-ion should not remain at the high-voltage ceiling of 4.20V/cell for an extended time. The Li-ion charger turns off the charge current and the battery voltage reverts to a more natural level. This is like relaxing the muscles after a strenuous exercise(See BU-409: Charging Lithium-ion)
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