Wisper batteries are the state of the art in lithium technology, unlike standard lithium batteries ours are lithium polymer, safer and more efficient. When coupled to our new advanced Battery Management System we believe we have one of the best batteries available.

To calculate the capacity of a battery on any electric bike, simply multiply Volts by Amps this will give you the number of Watt hours in the battery.  i.e. 37 Volts x 14 Amps = 518 Watt hours.  A Watt hour is the unit of electrical capacity; or how much power a battery will store.  

As an example I have used the test data from our three batteries. 

(taken from our road test results*)

Voltage          Amps            Capacity                 Range

37V                 14Ah                 504Wh               56 / 74 miles (90 / 119km)
37V                   8Ah                 296Wh               29 / 44 miles (46 / 71km)
24V                   9Ah                 216Wh               22 / 32 miles (35/ 51km)

*Road testing

The figures above were taken on a real road with a real rider weighing 11stone 8lb (74kg) (162lb) on a cold day (10 degrees centigrade) with some braking.  As opposed to a rolling road in a warm factory which is where most testing is done.

Wisper Leads the Way
Popular electric bike battery capacities and ranges.

Bike                            Volts    Amps   Capacity           Range
                                                                                    (minimum published)
Wisper 905se Li Po       37V      14A      518Wh             56 miles (90km)
Wisper 705se Li Po       37V      14A      518Wh              56 miles (90km)
Urban mover Li Po        26V      12A      306Wh              28 miles (45km)
Wisper 905eco Li Po     37V        8A      296Wh              29 miles (47km)
PowaCycle Li Ion           26V      10.5A    273Wh              27 miles (43km)
Kalkhoff Li Ion               26V      10A      260Wh              26 miles (42km)
Swiss Flyer Li Ion          24V      10A      240Wh              25 miles (40km)
Giant Twist Li Ion           26V        9A      234Wh              30 miles (48km)
Urban mover Li Ion        26V        9A      234Wh              21 miles (34km)
Wisper 806fe Li Ion        24V        9A      216Wh              24 miles (39km)
Izip Li Ion                      24V        9A      216Wh              23 miles (37km)

Range

The range of any electric bike can vary massively day today depending on some very simple factors.

Weight.  Not just the weight of the rider but also the weight of any luggage being carried or towed, effects the range you will get from your bike.

Wind resistance. Have you ever wondered why road racers wear Lycra?  It’s not just to show off muscles!  The fact is that if you were to wear Lycra on your electric bike (I don’t suggest for a moment that you do!) your range would be much higher than if you were wearing a huge overcoat and a nice big set of panniers!

Tyre Pressures. Always keep your tyres pumped up to the correct pressure, if you have ever had a flat tyre you will know why.

Air temperature. You will get about 15% more range on a warm sunny day than you would in deep winter.

Road conditions. A smooth flat road is much more efficient than gravel or grass for long range.

Hills. I realise you can come down the hill you just went up without using any power but you would have used a lot less power if you covered the same distance on the flat.

Throttle.  If you are lucky enough to live in an area that allows throttles without pedalling, you can use masses of power getting from start to cruising speed on the throttle alone. So try always to pedal up to a comfortable speed before you transfer to throttle.

Battery age. As batteries get older they start to lose the ability to hold a charge for as long as they did when they were new.  If you are using a 5 year old battery you will not get the same range as when the battery was charged for the first time.

There are of course other factors such as maintenance and wind speed but these are the most important points to remember.