Bike Shop tips: Safe storage and charging of electric bike batteries

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By Edward Benjamin, Senior Managing Director, eCycleElectric LLC and Chairman, Light Electric Vehicle Association

The very first thing I want to say is this: While it is true that lithium batteries, commonly used in e-bikes today, can catch fire…it is VERY rare for them to do so, for several reasons.

I suggest you are more likely to be injured by a falling coconut than to have a lithium fire at home. However, battery electric hand tool batteries have burned down a number of homes and businesses, and even mobile phones and laptops are known to combust. So being alert and aware of any and all rechargeable batteries is advisable.

But, being a “worst case scenario worry wart” myself, and a guy who is often working on batteries, or evaluating bikes and batteries, I have given some thought to what can happen, and how to avoid letting it happen. I want you to handle e-bike batteries in a way that reduces risk to really tiny levels.  And I want to repeat that while these steps are prudent and highly recommended, if you own an e-bike you  have little to fear.

If, however, you are a bike mechanic, shop owner, or hobbyist that works on electric bikes you will be handling batteries that have problems, have been damaged, or have a history that you simply do not know. And in some cases, as shown by the recent fires caused by cheap lithium batteries installed in ‘hover boards’, new products from low cost producers can be risky.

Even lead acid batteries can be a fire risk. [even the one in your car]. The only fire I have had was when a wire dropped onto a lead acid battery, shorting it, becoming white hot and burning off the insulation, scaring me out of a years’ growth, and being ejected from the office onto the back deck in less than 10 seconds. [It also gave my wife a lifetime supply of snarky comments about the “big bad battery expert who set fire to a ‘safe’ battery in his office!” ]

Here are some rules to follow:

  1. Read the owners manual, any caution stickers, and follow their requirements for safe charging.
  2. Only charge your e-bike batteries with the charger that was supplied originally with the bike or the battery. Create a process that includes clearly labeling chargers in your shop as to what goes with what. If you have chargers with the same connector, but for different bikes (not uncommon), hang a tag on those connectors that states what bike they are to be used with. Put a sticker on the charging port of the bike that tells you what charger to use.
  3. Charge only in a dry location. Rain, standing water, etc is bad for chargers.
  4. Educate your shop staff, customers and anyone who uses or borrows the bikes on the safety rules and…which charger goes with which bike.
  5. I like to use a timer. Mine was intended to control lights in the house, and I set it so that there is no power to the outlet during the night, and limits the length of time that the outlet is “on” to only 8 hours during the day time. This saves energy, saves me from moments of forgetfulness, and makes me look pretty professional to visitors.ed article
  6. Look over the place where you charge your bikes or batteries. If there was a fire, what would be nearby to add to the fire, or spread it? Charging next to your car means charging next to 15 gallons of gasoline – much more dangerous than lithium. Battery fires are hot, hard to extinguish, and generate toxic fumes and smoke. You are not going to be able to smother the fire, or pick up the burning battery and take it outside. So, choose a place that should a fire occur, damage will be minimized. I charge my bike on it’s kickstand, in the clear area of the garage a couple of meters from the wooden workbench, and a couple of meters from the car.
  7. Install a smoke detector over your charging area.
  8. Have a fire extinguisher located at the spot where you are going to be standing when you discover a fire. For example, hanging next to the door from the house to the garage. Maybe a second one on the other side of the garage. Additionally, have a bucket that can be used to carry water to the fire – reasons explained below. Use a 5 lb. or larger ABC extinguisher, or a big CO2 extinguisher, or both.
  9. If you charge batteries off the bike, I suggest doing so on a metal rack that has wheels on the bottom (very inexpensive at hardware stores) with the battery(s), and chargers on the rack. In the event of smoke, bad smell, or fire, you can shove it out the door quickly. Locate it closest to a doorway that you can use to eject the battery easily, quickly and without coming in contact with the burning material or breathing the fumes. Consider how you would get a bike out the door. I have a boat hook that could be used to drag just about anything outside and it’s 2 meters long.
  10. In the event of a fire, evacuating the building is more important than fighting the fire. Calling the fire department is essential. Keeping yourself safe and not breathing the fumes is more important than saving property. Even if the fire is safely moved outside, call the emergency services, for these fires are tough to extinguish.
  11. If you can get the fire outside, onto a driveway or other pavement, then you can consider extinguishing it yourself. To extinguish a battery fire, review this video at the base of this article.
  12. Write me and tell me your story, should you ever have a fire. They are so rare that I try to compile case studies. ed@eCycleElectric.com