Winter Battery Care For Your Wisper E-bike

Your lithium ion battery makes up a significant portion of the cost of your electric bike, so it makes sense to look after it!  Most of you have probably parked your bike for the winter, and there it will sit until the snow melts in spring.  A few easy actions now will ensure that your battery is rearing to go then, and for years to come.  I’ve tried to keep this article as simple as possible.  For further information on lithium ion battery care, check out the link at the bottom of this post.

A lithium ion battery will slowly discharge over time as it sits in storage.  If a battery is allowed to fully discharge, this will stress the cells in the battery and reduce the capacity and life of the battery.  During normal riding, the Wisper batteries have a battery management system (BMS) which switches off the electrical system when the voltage drops to a certain point i.e. the battery is not allowed to fully discharge and the cells are protected.   However, the BMS will not prevent a battery from slowly discharging as it sits in storage.  Therefore, it is important to ensure that your battery retains some charge over the winter months.  Unfortunately, it is also not ideal to put your battery in storage with 100% charge as this can put some stress on the cells.  The following actions are therefore recommended for battery care:

  • Store your battery with a partial charge, ideally 40-80%.  While charging, you can check the number of green lights on the battery indicator (with the key switched on) … aim for two-three lights (four lights is fully charged).  Another way of checking that the battery hasn’t reached full charge, is that the amber light on the charger is still on and you can hear the charger fan operating;
  • Depending on how fully charged the battery was initially, it will normally take about 1-2 hours to give the recommended partial charge;
  •  If you end up charging your battery to 100% (the green light on the charging unit comes on), go for a ride to discharge it partially before storing the battery;
  • Check your battery every few months of storage and give it a top up if the battery indicator has dropped to one light;
  • Ideally, the battery should be stored in a cool place.  Significantly elevated temperatures over prolonged periods can reduce battery capacity.  Also avoid freezing the battery.

Correct storage of your battery as detailed above will significantly increase the lifespan of your battery.  A well maintained lithium battery will last up to five years, whereas a poorly maintained battery can be badly damaged over just one winter!

For more detailed information on batteries and how to care for them, check out the excellent online resource at the following link:

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

 

Wisper Electric Bikes Power the Police!

The City of London (UK) recently rolled out a number of Wisper electric bikes as part of their cycle squad.  A number of studies have shown that two wheels is the quickest way to get across an urban area … so all you dodgy geezers watch out!

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