Hi Jedany chance of some details on the changes you are making? will you be adding a off-road/turbo mode ala the Ezee bikes?
thanks
Jed
Might you do an equivalent improved 705? My personal preference is for a step-through, upright-position bike. The 705e is my kind of style, but right at the top of my "acceptable" weight range. If you could shave a bit of weight off, and give it that 4-mode switch, I'd be seriously interested.
Mary
Hi David, thanks for that. I'll live with my Urban Mover for a while, but keep an eye on your website for next year.Hi Mary, yes there will be a 705Se available in 2008, but until then we only have the standard 705e.
Best regards David
Hi Frank as promised I have some answers for you from our battery guys.My concerns on Lithium batteries come from reading on this forum and in A to B magazine. They are:
I think this probably comes as a result of companies not specifying the correct type of lithium ion battery. All battery technologies such as Nickel Cadmium, Nickel Metal Hydride, Lead Acid and Lithium ion have product variants designed for high temperature, long cycle life, high rate discharge etc etc. Many Lithium Ion cell suppliers in China do not have their technology optimised for applications such as E-Bikes and therefore although their product may appear attractive on paper with good capacity, light weight etc etc the performance under high rate discharge is not so good and therefore they can have a high voltage drop under high load conditions. A correctly designed lithium battery should however be at least as good and perhaps even better at high rate discharge than all other battery types. The hybrid cathode material we use in our E-Bike batteries allows peak discharge at up to 5 times to rated capacity of the battery with very little voltage drop. Based on our 36V 10 Ah this means the cells can easily deliver 1800 Watts of power if needed. The limitation is therefore usually caused by the battery protection module as follows :1. Cut out on hills. Because the voltage of a lithium battery drops under loading, it can sometimes trigger a cutout. As peak loading occurs when you are going up a steep hill, it is pretty inconvenient. This seems to be more of a problem on higher powered bikes. People have reported it on Ezee bikes (and I think also on the Sparta Ion), but there have been no reports of this happening with Powacycles, where the much lower powered motor does not make such demands on the battery.
It is hard to make a comparison without testing products under controlled conditions but it is widely acknowledged by cell manufacturers that lithium ion cells display better cycle performance and lower capacity losses under almost any condition. Again this assumes that the cell type used is suited to continuous charge and discharge characteristics of the E-Bike. As detailed before all batteries will lose capacity as a result of being charged and discharged this cannot be avoided but based on our standard specification then you should expect around 500 charge and discharge cycles and still have 70% of the original capacity. Given a daily commute of 5 days a week this should work out to around 2 years use before a significant loss of capacity is noticed. I can only assume that if many lithium ion users are reporting rapid capacity loss then the quality of the cells they are using must be very poor.2. Rapid loss of capacity and hence range with normal usage. People talk about losing anything from 10%-100% of capacity per year of life. The problems seem to arise if you use the battery to anything near its capacity (ie run it down past half charge). However, that is what I would want to do as I have a 25-mile return trip to work. NiMH by contrast seems to be much more robust. People on this forum report no loss of range after 2 years with deep discharges being possible.
You can only make a judgment based upon the specification supplied by the manufacturer and your belief in their figures.Therefore my questions are how can I be sure that a lithium battery would give satisfactory operating performance - ie ability to climb long hills without cutting out and ability to get me to work and back without having a very short life?