Mark, Your numbers are too optimistic. I have built 3 bikes to date with good instrumentation to measure efficiency. My first bike averaged about 120 watt hours per mile. My new nicad one seems in that 120-130 WH/M range too under conservative driving. The ninja webpage numbers are completely unrealistic on price and range. I have a CycleAnalyist www.ebikes.ca on one of my bikes and it gives real time WH/M numbers which are teaching me a lot about how to drive for range. The most frequent mistake people make in there pack size number (I did it too the first time) is to ignore the Peukert's effect in lead acid batteries. This essentially shrinks usable capacity of the battery as discharge rate increases. At 200 amp discharge rate my 100 ah batteries could only supply 35 ah because of their Peukert's exponent. That is part of the reason I am loving the NiCad, this effect varies by construction and chemistry type. Garret Mark Eidson <[EMAIL PROTECTED]> wrote: No, I was not familar with this site. I looked at using 2 Eteks or Perm Motor 132s but was concerned about heat living in AZ. There has been an on going string on the EV list about Etek failures and having to add blowers for cooling. These smaller motors will be easier to fit in the Ninja frame but build up heat quickly due to low mass. The Perm Motor is uni-directional so be careful. I put in a bigger motor than required due to my chassis design. There is a narrower version of my motor that is probably better for your conversion. I am skeptical about the range stated on the website. My bike has about a 30 mile range to 80% DOD. You should get about 100WHrs per mile. 20 miles means you pack needs to be 2kWHrs/.6 or about 3.3KWHrs. For a 72 volt system you will need batteries rated at 46.3 AHrs for .5-1 hour discharge rate. Going over 60% DOD is going to significantly shorten you lead acid battery pack life. My round trip commute is 13 mi and I get about a 35% DOD so my battery life should be OK and I have enough capacity for side trips. I went with individual chargers for the AGM batteries since there are only 6 and this was cheaper than a single charger with balancers. The 72 volts with the 4.74:1 fixed ratio drive my motor is rev limited to a top end of 55MPH. I'm looking to change the drive ratio to 4:1 or 3:1 to improve top end speed. Acceleration is very good with the current ratio so I have room to lower it. Direct drive requires high current for good acceleration that is why I choose the Zilla and AGM batteries.
On 9/14/07, SteveS wrote: > I assume you are familiar with: > > http://www.electric-bikes.com/Ninja.htm > > Can't help beyond that since you are already a step ahead of me! > > - SteveS > > > Robert Smith wrote: > > Hi all, > > I just subscribed at the suggestion of someone on my EV miallist. EV > > list was very helpful, but thought it would be good to pick some of > > your brains here. > > > > I am starting on my first EV project. My son and I are converting a > > 1991 Ninja motorcycle. Lead batteries are planned, but I am curious > > of the advancement and availablitiy of LiIon, NiCad, etc.. and wonder > > if I should go a different > > route. Goals are to have a speed about about 50mph and a range of 20 > > or more. It's a first bike for riding in 15 years as well. Been > > itching for a motorcycle for the past two summers! > > > > In thinking about this conversion, what specs are important? > > > > Thnaks > > >RC > > > > > > --------------------------------- Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more.
