Fire safe battery charging

[krokan]

How do you charge your ebike battery? Do you plug charger directly to your ebike charging port or do you remove the battery from bike and charge the battery in some fire safe box?

I'm thinking about welding of some metal box where I would charge the batteries, does it worth it?

 

[krokan]

Even some Tesla cars burned down and they have probably better BMS and battery monitoring than any ebike battery.

 

[krokan]

That is a good idea to build it out of bricks!! Not kidding! Or metal box with these fire proof bricks inside, like fireplace!

 

[urastus]

I'm not sure I'd panic yet. They used a wrong charger? Consider that we're still driving internal combustion cars that we fill up with highly inflammable liquid. That liquid is stored in big reservoirs where we go to buy it. We then drive these machines around on the road with many other intolerant road users and we're all carry 20 to 40 litres of highly flammable liquid , all the time!

Shimano has two model chargers for the e8000, I have the slow one. It's actually better for the battery and of course generates less heat in the battery while charging. Other folk whinge about this charger, I'm OK with it. I also use a timer - that must limit the potential danger to some degree by minimising the time that there is actually power to the charger.

 

[steve_sordy]

My first emtb had a non-removable battery, so no choice there. No problem either.

Next emtb has a removable battery which I removed once just to see that it did come out and go back OK. But it has stayed in the frame for the last year. The only concession I make to any potential fire risk is to place the charger on the concrete floor of the garage rather than the sisal matting that the bike is stood on.

I use a timer on the charger, timed to end just as I enter the garage to collect the bike. Maybe I should start checking the frame for temperature?

 

[krokan]

My first emtb had a non-removable battery, so no choice there. No problem either.

Next emtb has a removable battery which I removed once just to see that it did come out and go back OK. But it has stayed in the frame for the last year. The only concession I make to any potential fire risk is to place the charger on the concrete floor of the garage rather than the sisal matting that the bike is stood on.

I use a timer on the charger, timed to end just as I enter the garage to collect the bike. Maybe I should start checking the frame for temperature?

You can buy Sonoff temperature smart switch.
You can disconnect the charger automatically if the temperature rise to some suspicious temperature. (Or/and you can be notified). It is Sonoff TH10 with sensor... On Ali for like 10$

I use it for my 3D printer..

 

[Waynemarlow]

Best box going for our size batteries

British Crafted Steel Toolbox: Quality and Timeless Style - Gloss Red | eBay

<p>In search of something special? Look no further - our British crafted steel tool box is ideal for quality-minded individuals. Robust rigid powdercoated steel guarantees longevity, with a fold down metal carry handle, riveted hinges, and dual clasps for extra strength. At 40 x 15.5 x 12.5cm...

www.ebay.co.uk

and best fire board.

Stove Firebrick Fire Board Fire brick Vermiculite Fireboard Heat Resistant | eBay

With the feature of heat insulation and fire prevention, Vermiculite Fireproof Board / Brick is widely used as a thermal insulation and refractory material. And the fireboard can be worked easily with woodworking tools.

www.ebay.co.uk

 

[MountainBoy]

Even some Tesla cars burned down and they have probably better BMS and battery monitoring than any ebike battery.

Some early Tesla burned up but the media blew it all of proportion considering that statistically, your gasoline car is about 10-11 times as likely to catch on fire and burn up. Do you worry about parking your gas car in your garage?

What is the most common way Tesla have had battery fires?

#1 High speed crashes that physically damage the batteries. Even here EV is much safer than an equivalent crash in a car fueled with gasoline. Because steel sliding on pavement makes sparks and spilled gasoline turns into an instant fireball in the presence of sparks.

One over-hyped Tesla battery fire was caused by the owner accidently discharging his handgun inside the cabin. It went right through the battery which caught on fire a few hours later. Other Tesla fires have been caused by charging the battery improperly. Always use and charge a battery using the manufacturer's approved current and voltages.

Lithium ion batteries are less energy dense than gasoline, but they must still be treated with respect.

 

[krokan]

I'm not arguing, just saying that no BMS or any other electronic equipment will 100% protect you from the fire. I just want to avoid spreading of the fire.

 

[MountainBoy]

I'm not arguing, just saying that no BMS or any other electronic equipment will 100% protect you from the fire. I just want to avoid spreading of the fire.

I just charge my eMTB battery when I'm at home and awake. That way if there is a problem, I can take care of it without burning my house down! If you have a fireplace or hearth, you could charge it there for an extra measure of safety.

 

[Kiteboy]

I charge mine on the pool patio, 10 feet from pool. It is under cover and in the shade and I only charge it when I'm at home. I also keep batteries in the top of a short tool box with sliding table top feature covering the large top compartment. The thought there being I could roll the box out of the garage if batteries caught fire while charging in it. I scrapped that plan when I considered that my bike tools and new spare parts are kept in the drawers below and they certainly would not survive a battery fire.

 

[rod9301]

You can buy Sonoff temperature smart switch.
You can disconnect the charger automatically if the temperature rise to some suspicious temperature. (Or/and you can be notified). It is Sonoff TH10 with sensor... On Ali for like 10$

I use it for my 3D printer..

Do you put the temperature sensor on the bike battery?

 

[krokan]

Do you put the temperature sensor on the bike battery?

I'm not using it currently for my bike but for my 3D printer to monitor dangerous temperature. It can be used the same way for battery charging monitoring though.

 

[Slapbassmunky]

I've built many e-bike batteries over the years. The concerns raised here are all alleviated by very strict pack control by the BMS, the slightest hint of anything going out of strict parameters and the pack is shut down.

Physical damage is the biggest danger to a well designed and engineered battery pack - which all of our top tier e-bikes have.

FWIW I charge my Bosch 500 & 625 packs where I want to within reason. If I'm happy to charge it in a pub sat next to complete strangers while I'm outside in the beer garden then I should be happy to charge it in my house. Would I do the same with my RC racing LiPo's, hell no! But they're a totally different beast with a totally different rulebook.

 

[Slapbassmunky]

You can buy Sonoff temperature smart switch.
You can disconnect the charger automatically if the temperature rise to some suspicious temperature. (Or/and you can be notified). It is Sonoff TH10 with sensor... On Ali for like 10$

I use it for my 3D printer..

The BMS already monitors pack temp and will disconnect the charger if it's too high. If the temperature rise is too fast over a given time it will brick the pack.

 

[MountainBoy]

Physical damage is the biggest danger to a well designed and engineered battery pack - which all of our top tier e-bikes have.

FWIW I charge my Bosch 500 & 625 packs where I want to within reason. If I'm happy to charge it in a pub sat next to complete strangers while I'm outside in the beer garden then I should be happy to charge it in my house. Would I do the same with my RC racing LiPo's, hell no! But they're a totally different beast with a totally different rulebook.

I agree with that but there are plenty of e-bikes that have unsafe battery systems, yeah, they are not the top tier, mainstream brands.

Most importantly, I would not trust ANY used battery because you don't know if it has been rebuilt by a third party. I consider all batteries rebuilt by someone other than the actual manufacturer to be an unacceptable risk.

Li-ion batteries are actually very safe as long as the system they are used with is properly designed and the battery has not been physically damaged. Of course, gasoline is also very safe when used within the proper parameters! Used improperly, it's far more dangerous than most people understand.