You are not biking far without a good ebike battery. There are many types on the market today. Read on to make sure you get the right one. Read a little more for care and maintenance tips.
There are two basic batteries in use today: Lead-Acid (Pb-A) and Lithium-Ion (Li-Ion). Nickel Metal Hydride (Ni-Mh), Nickel Cadmium (Ni-Cd) and a few other chemistries are used to a lesser degree.
Pb-A batteries are most often 12 volts in amp-hour ratings from around 8-18. Many 36 volt ebikes for instance use three 12 volt batteries, 48 volt systems use four, and so on. Pb-A systems are inexpensive and reliable, but heavier and shorter lived than Li-Ion batteries.
Ebike Pb-A batteries are most often sealed lead acid, or SLA. This is to prevent spillage or excess gassing. Gassing is best regulated by the VRLA or valve regulated lead acid battery.
Most of the battery packs above include the battery management system - BMS. Most reputable dealers will provide the BMS with the pack.
The BMS is a circuit board designed to balance the pack charging and discharging, as well as to prevent over and under charging. Under charging a Pb-A pack for instance is a bad day for the battery pack. Under charging an Li-Ion pack pretty much ruins the pack.
Prices on the tables will vary some, but should give you an idea of the basic costs involved with replacing your ebike battery pack.
Care and Maintenance Facts and Tips
- Read and follow the manufacturer's charging specs
- Use a smart charger designed for your battery pack only
- Keep your pack warm; batteries lose a lot in cold weather
- With SLA batteries expect 300 to 400 or so charge cycles
- Many Li-Ion batteries are rated to 1500 plus charges
- Cycle batteries to about 80% maximum capacity to prolong life
- Cycle batteries less and you will get more charge cycles
- If your battery fails to fully charge, or drops off you may have a bad cell
- Li-Ion Ploymer type batteries can not take shock well, so pad your pack!
Li-Ion batteries are commonly LiFePo4 chemistry. The Bionx system uses a LiMn chemistry, which is claimed to be superior. Li-Ion batteries are constructed of individual cells. The number of cells determines the voltage and amp-hour rating of the finished batteries. A 36 volt LiFePo4 battery would have 12 individual 3.65 volt cells wired in series. Li-Ion batteries weigh about 1/3 as much as Pb-A batteries, last 3-4 times as long as Pb-A (more charge cycles), and cost 3 times as much.
eBikes batteries use lead, lots of lead. Demand for 2013 is likely to be well over some 500,000 tons! Of that, about 190,000 will come from recycled batteries. Lead has been selling for about $2,300 per ton or around a dollar a pound.
The Varta Battery company has produced a 36.5 volt eBike battery holding 14.5 amp hours
capable of 25 amp continuous and 30 amp peak discharge.
The new VARad battery pack is claimed to tip the scales at just 7.7 lbs (3.5 kg).