We are often asked the best way to charge batteries to get the best life out of them. Conveniently, the same answers generally apply for how to maximise battery safety.
Lithium battery safety is a hot topic around the world. Visitors to Eurobike this year would have seen there was a stall marketing a battery charging locker to e-bike shops that automatically shuts its doors if smoke is detected!
And of course we had our own share of battery fire drama this year, with a recall of a batch of batteries from 2016.
This has led us to create the information below to not only minimise fire risks and consequences, but also to increase the longevity of your battery, because a stressed battery doesn't last as long.
We thought long and hard about this one, as we were never comfortable with throw-away lines like 'always supervise your battery while charging' - they just aren't practical for actual people in real lives and simply move the liability to the consumer. So please send us your feedback about what you think of the tips below.
Battery Safety Manual – by Maurice Wells, Glow Worm Bicycles, 2019
The safety of both our customers and their possessions is important to us. Our electric bike batteries are lithium-ion batteries, built with the latest technology, compliant to relevant safety standards. When charged, lithium-ion batteries contain a high level of energy. If a fault occurs internally (not visible) or externally, any lithium ion batteries can catch fire.
Therefore it is very important to minimise both the risk of this occurrence through proper battery care, as well as minimising any potential consequences, through best charging practices.
The information below is relativey generic and may be useful for any lithium battery you own. Please keep in mind though, the context of it is based around the batteries that we have experience in selling – typically eZee and Bosch batteries. Bosch for their part, has their own guides and manuals too.
The information included here was created with forethought and care. However, we can not guarantee that all information within is completely accurate or error free. No liability can be accepted for damages which come about either directly or indirectly from suggestions in this post, so far as there is no deliberate intention or gross negligence from Glow Worm Bicycles.
- Protect the battery against physical stress. Keep away from:
- excessive exposure to direct sunlight (eg daily storage of battery or bike in a window facing the sun)
- direct heat sources such as home heaters or fires
- submersion in water
- Take care of the battery from physical damage. Do not allow it to be dropped, carelessly transported (eg in a backpack without proper protection, or sliding around in the boot of your car). If your bike has a serious crash, return to your shop for inspection of bike and battery.
- Keep away from any small metal objects when the battery is not installed into the bike. Small tools, scrap cabling, paper clips etc or anything that could short circuit the battery terminals.
- Do not open the battery. This voids the warranty and may increase risk of fire.
- Keep the battery away from children
- Understand that your battery will not last forever. There will come a day when it needs replacing. The visual exterior condition, its functional capacity (how far you can ride on it compared to when it was new) and its age are all factors. Experience has shown us a typical result is around 5 years before a battery needs replacing. Continuing to use a failing battery can increase risks. When you do purchase a new one, keeping your old one as a 'spare' around your house is an unnecessary risk – return it to your supplier for safe recycling.
Charging Best Practice
Lithium batteries are at their highest level of stress when at full charge. This includes when the battery has finished charging, even if disconnected from the charger. The tips below will not only minimise the chance of any adverse incident, but they will also help to increase the longevity of your battery. The tips below are to help you assess the best charging practice for your usage patterns and home situation. Not all scenarios are the same and it's up to you to decide what is best for you.
1. Minimise how many hours per week your battery is at a full state of charge. Depending on your situation, this could be done by:
- charging every few days instead of every day
- program a power point timer so that your battery begins charging at dawn and has charged sufficiently when you're ready to leave the house on your e-bike. The ideal is if it's not quite fully charged when you leave.
- For a shared or fleet e-bike situation, consider instructing users to put it on charge only when it reaches half full, as opposed to every time a short ride is taken
- for irregular users (eg holiday homes), do not leave your battery on a timer to occasionally 'top up' the battery. This is unnecessary and keeps the battery at a high state of stress
2. Best locations for charging on your property. Not all home situations are the same and your own daily patterns will also influence where is the best place and time to charge. Some situations are inherently safer, such as outside the house, but are more difficult to supervise. It's up to you to assess the risks and make a decision for what works best in your space and life style.
Make sure your home is fire safe, regardless of your ownership of an e-bike. This means (hard wired) smoke alarms and not 'dead locking' your doors. Refer to the local fire department for more tips
do not charge your battery underneath curtains, in a cluttered area, near solvents and paints or directly between you and your exit from your house.
Is there a suitable place you can charge that is not in the home, but still protected from weather (eg carport or back porch)? If so, this is probably the best place to charge your bike. It is probably worth the effort to install a power point or organise a cord in that area.
If you must charge in your home, where can you charge that has the best ventilation (next to an open window) and the fewest flammable materials around? This may be the laundry, the fire place (obviously when not being used for a fire!) or a kitchen bench.
Leaving the battery in the bike while charging is ideal if you can. It reduces occurences of dropping the battery and the bike's frame is metal and keeps the battery some distance away from other materials.
The charger should always be on a clean, dry, flat and fire proof surface, as the charger does create heat while charging.