Using your E-bike battery.
E-bike lithium-ion batteries should give 5 or 6 years service. Then, you will begin to notice that it does not take as long to charge and, the range becomes reduced.
Many e-bikes run on a 36V system, but other sports e-bikes use 43V, 48V and 54V for increased performance. The batteries are made of a number of cells – a bit like AA batteries. They are known as 18650 cells, which are combined in “series” and “parallel” in your battery to give the capacity which will be printed on the label.
Volts, Amps & Watts
Common sizes are 36 X 8.8Ah, 10.4Ah, 15.6Ah & 20Ah. As the amperage increases, so does the price.
The watts that these batteries can deliver to your motor is given by the formula V X Ah = W. ( Volts X Amps = watts) So, a 36V X 10.4Ah battery will deliver 375 Watts. If you have a 48V system, a greater number of watts are needed to provide a10.4 Ah battery. 48 X 10.4 = 500 watts (499.2).
36V is known as the “nominal” voltage of the battery. When fully charged, it will read 41.4V. As you ride the bike on pedal assist, so the voltage will reduce. On a 36V battery, when it reduces to about 28V, the battery will shut down and the bike will no longer have any pedal assist. This is because the battery is fitted with a BMS (Battery Management System) which is designed to do this to protect the cells. Lithium cells that run right down will never charge again, so the BMS stops this before this happens.
Batteries do not like being left fully discharged, and are best recharged within 24 hours. But, first, let it cool down for about an hour before charging.
Battery Cycles
Lithium batteries have no memory and so can be charged after every ride, so you know that you have a full battery next time you go out. Most batteries are rated on the number of charging cycles that they will take. 800 cycles is a figure often seen. But if you charge your battery when it has only been -say- 20% used, this is only calculated as 20% of a cycle. So, you can charge it 5 times like that to be equivalent to 1 cycle.
Battery Safety
Well constructed lithium batteries for e-bikes are very safe and should always be charged with the charger recommended by the manufacturer. For further advice and warnings about ebike batteries can be found on the UK Government website.
Store your battery in the dry and protect from frost.
How far will an ebike Go?
See our blog here
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