Lithium Powered Electric Bicycle Battery Care
Electric bicyclesare gaining steam as the newest "green" transportation technology.Electric bikes are Electric bicycles are often lithium poweredthrough the use of lithium ion batteries, which have relativelygood energy density. Many electric bikes achieve a range of 40+miles on a single charge - and that's for electric power alone.When the engine is used to aid biking rather than as the solesource of power, electric bikes can achieve much larger range. Thetop speed of electric bikes can be as high as 34 mph, thoughtypical cruising speeds are in the 20-25 mph range. The bikes slotinto the category of light electronic vehicles (LEV's), which are arapidly growing segment of the transportation industry.
Though electric bikes have a number of advantages over internalcombustion-powered bikes, such as legality, noise, and emissions,their use of lithium ion batteries means that they require someregular care. The remainder of this article provides useful advicefor how to care for your lithium ion battery.
Lithium Battery Care
Lithium ion batteries use the slow movement of charged lithiumparticles across a battery to store energy; the batteries rechargeby, in essence, transporting the ions back across the battery. Thisallows the batteries to be lightweight and durable, and typicalbatteries can endure about 1000 full recharge cycles. This numbercan be skewed downward by several factors, however, so to get asmuch life out of your battery as possible it is necessary to takecare of it. Additionally, lithium batteries lose storage capacityover time; luckily, careful use and charging will extend thebattery's useful life.
Temperature and Battery Life
Lithium ion battery life is adversely affected by temperatureextremes. High temperatures cause irreversible damage to lithiumion batteries; this damage can be caused during charging or by highoutside temperatures. A fully charged battery stored at 40o C (104oF) for a year will have lost 35% of its original storage capacity.The same battery stored at 0o C (32o F) loses only 6% of itscapacity. The takeaway message here is that you should store yourelectric bicycle in as cool conditions as possible. This may meantaking your bicycle indoors in the summer (always a good idea withexpensive bikes, anyway), or storing it in a cooler area. Anothersource of damage is heat from charging, which is most serious inbatteries containing carbon anodes. Be careful not to overchargebatteries (such as by leaving them to charge overnight), as theresulting combination of high temperature and charge is verydamaging.
The second most important bit of advice for lithium battery care isto avoid storage with a full charge. The recommended charge duringstorage is just 40%. A 40% charged battery stored in 40o Ctemperatures loses only 15% of its charge in a year, compared to35% for a fully charged battery. Only charge your battery beforeyou intend to use it, and never store it with a full charge.Conversely, the batteries should not be stored with very lowcharge, as this too can erode battery capacity. Ideally, thebattery should be stored at cool temperatures with about a 40%charge (or just under half, if your gauge isn't tooaccurate).
One important caveat to the storage temperature: lithium batteries do not operate well when cold. The battery capacity will be temporarily lowered when the battery is very cold, so warm it up before use. This loss in storage capacity is only temporary, however.
Some of the storage loss can be averted by fully charging and discharging the battery at least once each month. With proper care, you should be able to get up to 3 years of good use out of the battery.