E-scooter explodes indoors

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linw

2849 posts

Uber Geek

#3110004 31-Jul-2023 11:41

Having been a model electric plane flier I understand the worry about Lithium based batteries.

But my batteries were only 12V 2200mA ones and they were capable of burning your house down.

Car, scooter, bike batteries sound truly scary. If anything goes wrong...............

The world really needs safer batteries.

Rikkitic

Awrrr
18663 posts

Uber Geek

Lifetime subscriber

#3110010 31-Jul-2023 11:55

For what its worth, I do use timers on all my charging devices. They are not expensive and I have several. I also don't let chargers run unsupervised. The timers are just insurance in case I forget something.

Plesse igmore amd axxept applogies in adbance fir anu typos

johno1234

2808 posts

Uber Geek

#3110047 31-Jul-2023 13:14

I just go with the manual. If it says OK to leave the batteries on the charger all the time I believe them. Should I not?

Looking at the manual for my EGO garden tool batteries:

5. When the battery pack is fully charged, the
charging indication LEDs stop alternating and will shine green continuously. The
power indicator on the battery pack will go out. Wait until the cooling fan stops,
remove the battery pack from the charger and disconnect the charger from the
power supply.

6. The battery pack will fully charge if left on the charger, but it will not overcharge.
If the battery pack remains on the charger for one month or more, it will perform
self-maintenance and drop to 30% charge capacity. If this occurs, reinstall the
battery pack on the charger to recharge it fully.

So 5. suggests not leaving the battery on the charger and 6. suggests if you do it will deal with it.

I want that battery fully charged when I need it... do these batteries discharge over time if off the charger?

tweake

2391 posts

Uber Geek

#3110117 31-Jul-2023 14:11

frankv:

When FENZ guy said to not leave them charging for a long time, what's a long time? Is 4 or 8 or 12 or 24 hours a long time? Because on occasions I could easily leave something on charge for 12 hours or more. And an electric screwdriver in the shed might be left for a week or more. Surely, if use like that could cause an explosion, the charger or device should have a timer or current sensor or whatever.

some cheap chargers do not shut off, they rely on the bcm to do that.

whats even worse is the really cheap stuff that doesn't have high voltage cut off in the bcm (or no bcm at all), it relies on the charger to turn off. hence they will overcharge and damage the battery. of course the manufacture gets around that by putting a label on saying that the correct original charger must be used. there was a dvd player (i think) that came in with an incorrectly wired lead. instead of replacing the lead they put a sticker on it saying to only use it with the machine.

wellygary

8328 posts

Uber Geek

#3110134 31-Jul-2023 15:26

linw:

But my batteries were only 12V 2200mA ones and they were capable of burning your house down.

If this explosion had happened in a normal residential house is it quite possible that the place would have burnt down,

The one "positive" thing about this accident was that it happened in a sprinklered building, which prevented the fire from spreading to other combustible items (Couches, cupboards, benches etc) -

Water won't put out a Li fire, but the deluge from sprinklers will soak regular combustible items enough to stop them igniting.

MarkM536

309 posts

Ultimate Geek

#3110145 31-Jul-2023 16:11

tehgerbil:

I would love to see more scooters with built in chargers, was a selling point for the ninebot max, all I needed to supply was a 230V cloverleaf cable to charge the thing.

The weakest point of any charger is the barrel adaptor which will degrade and allow for shorts over the many insertion cycles.

Awful idea by Ninebot for an escooter.

Thermal time-lapse I shared shows around 40*c during winter, in summer with higher ambient temperature the charger can easily get near 60*c on the surface. Inside on the heatsinks is probably around 65-70*c.

Reason #2; a charger is protecting the battery if there is a power surge. But regardless of how effective surge protection is, a lighting strike on the power lines will make that charger blow up like a firework.

Reason #3; a charger built in makes it easier for stolen escooter/ebikes to be charged by the thief/buyer.

No clue how you judge the plug is a weak point. Most of the cheap escooter use a barrel plug, the higher priced units use something like a 3-pin screw on connector.

I do agree partly that the connector should be different. IE it works like an electric car charger with a data signal, so it only sends power when it's plugged in fully.

ezbee

2406 posts

Uber Geek

#3111121 2-Aug-2023 17:15

The more cells in series the bigger the risk, if subject to cell imbalance.
Imbalance can turn normal safe charging into a lottery of when a cell pushed outside its safe operating area will give out.
Heat generated then takes out its neighbors that were perfectly fine.

Does your typical 'low cost' scooter with a number of batteries series manage or monitor cell balance?

These batteries are under very high stress much more than laptop batteries that at least monitor cell balance.
Its a bit off that laptop batteries just limit capacity and eventually disable rather than actively balance but at least they do the minimum.

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