Smoke alarms and electric bikes!!!

[Baitrunner]

The outlaws have a couple of electric bikes as they still like riding, but are not as fit as they used to be.

Last night one of the batteries exploded and caught fire while on charge! Luckily they were still awake and the smoke alarm worked.

Apparently the house stinks of burnt battery now and they got taken to hospital to be checked over for smoke inhalation (one of them is asthmatic as well).

Sounds like they will be fine and the house just needs fumigating as they disconnected it and put the fire out quickly.

Just a warning really for anyone charging a battery up to be careful - Those of us who charge our smartphones up at night by the bed are in more danger than others as well - those unfused charger plugs can be a danger.

Check those batteries folks (in the smoke detectors that is).

Stay safe.

[Baitrunner]

Just managed to catch up on the situation and apparently the batteries were not even on charge!!.- The outlaw brings them in during the winter so they don't deteriorate and it looks like one had an internal short that caused it to go off.

Both batteries taken away by the Fire Brigade and hopefully a recall to other owners to prevent a bigger disaster happening.

[Baitrunner]

And one final note - The fire brigade were top guys when they attended the scene and it sounds like the insurance company are all over this trying to sort out accommodation for the outlaws (I even offered to put them up) and repairs.

So there are some really good people and companies out there if your lucky enough to find them.

[Guest]

Although it's quite rare, Lithium Batteries can indeed overheat and explode while charging.

Most instruction books for phones and tablets carry an obscure caveat like "never charge unattended", or "only charge on a fire-resistant surface".

When they get up to the size and amperage used in electric bikes and model aeroplanes, they can easily cause a house or garage fire. Phones and tablet batteries are around 5 volts and less than an amp, whereas a typical eBike battery is 36 volts and 10 amps.

That's a great deal of stored energy, and if the automatic electronic management of the charging goes faulty ( the "BMS", or "Battery Management System" ), they can go up like an incendiary bomb.

I've been a fan of ebikes for a number of years now, and I always remove the battery from the bike and charge it in a large steel fireproof box, (which cost £10 in Sainsbury's as a "garden toolkit" box.)

Radio Control Model enthusiasts use readily available and cheap fireproof charging bags, so I bought a couple and use them for my mobile phones and tablets, (they only cost a few pounds).

https://www.google.co.uk/search?q=battery+charging+bags&source=lnms&tbm=isch&sa=X&ved=0CAgQ_AUoAmoVChMIk668vLblyAIVyI0sCh3lEgnO&biw=1472&bih=917&dpr=0.9

There are many videos on Youtube showing the force of one exploding:

 

[Baitrunner]

I will pass that on to the outlaws - but in the second post you will see they were just laying there and not being charged. As you say though a fault in them and kapow with that much energy waiting to go.

[Guest]

Yes, I only noticed what you'd said about them not being charged after I made my posting.

That is unusual.

Lithium battery packs for ebikes are either lithium iron or lithium polymer (LIPO), and each cell has a charged voltage of around 4v, so to get the 36 or 48v and amperage that bikes run on, they have many cells in a parallel and serial arrangement.

That's why they need their built in "battery management system" which automatically monitors each individual cell voltage during charge and discharge.

Without it, one or more cells could short out, and then allow the other serially connected cells to go to a higher voltage, which would inevitably cause them to explode.

We're luckier with mobile phones and tablets, because they run at much lower voltages, so they do not need multiple cells to be connected in series to hike the voltage up.

The only hazard from a standing lithium battery is that it could gradually drop below about three and a half volts, at which stage it would be irreparably damaged, but be even less likely to explode.

(That's why it's risky to buy a secondhand ebike that has been left neglected in the shed for years, the battery will usually be shot.)

 

[Labrador]

What make of bike are they?

[Baitrunner]

Not sure but will find out for you. 

[grendel]

there is nothing unusual about lithium batteries catching fire, in the early days they caused many laptop fires, if the internal voltage gets too low, and they have not got cutout circuits, then they can catch fire when charged, they were the cause of those plane fires caused by the new battery packs, in the model car plane and boat world battery fires are a well known phenomenon, a fire can be caused by damage to the battery, by charging, or just by a trace of water seeping in (lithium is highly reactive especially with water).

They may be very good batteries, but they are by no means the safest battery to have or use, and require a great deal of respect. you can get an explosion if you try and put a nail through one. just google lithium battery fire / explosion, and you will see the number of incidents - the tobacco vaporisers that catch fire - lithium batteries.

here is a comprehensive study on the safety aspects of Lithium ion batteries:-

http://batteryuniversity.com/learn/article/lithium_ion_safety_concerns

[Baitrunner]

JR, the bikes are made by Life Cycle - They have a gents Mountain Sport and a ladies Alpine Sport which use the same size battery. Not sure which one is was off.

The insurance company are taking them away and may be following up with the manufacturers.

On another note they are insured with Saga and they have been really good.

[16E]

There was a fire in the roof area of a Boeing 787 at Heathrow last year. It was parked up, switched off and not connected to shore-power.  The cause was from the Li-on battery in the locater package in the saloon roof.  Root cause was a wiring and assembly fault on the battery pack.