Re: [ElectricMotorcycles] Another dang newbie!!

[Jeff Blamey]

A matter of omission on my part was the usage of the bike. My aim is a top speed of 60mph, but most of my driving (95%) will be 0-45 in town. So my range (goal) of 30 miles is based on local travel, low speeds, and not all in one bite. I would be satisfied with 20-25. I can almost drive to work all week without charging, there is already  a scooter on a power plug at work, so's I can plug in next to him if need be.

I do hope to test the range with someone driving the chase vehicle with my trailer on the back end. We can see how close the theoretical matches up with the real.

When I wanna go fast (or far) it's time to break out the old trusty Beemer.

According to Garret I will be pushing the Honda (literally). Thanks for the information Garret . Actually I rather bypass the Ni-cads for the next gen lead-acids the Caterpillar spin off company (Firefly Energy Inc.) is promising to produce. Li-Ion and Li-Polymer are too expensive for my blood.

I thought thru battery placement, battery capacity, and the resultant decrease in range to retain nimble handling. I got dumb lucky on the broken VF500 popping onto the radar, did I mention the new tires it came with?

Peace

Jeff

-----Original Message-----
From: Garret Maki <[EMAIL PROTECTED]>
Sent: Mar 5, 2007 2:14 PM
To: ElectricMotorcycles
Subject: Re: [ElectricMotorcycles] Another dang newbie!!

Jeff,

I don't want to discourage anyone from trying, but lets look at those numbers. 

72v x 55ah 20 hour rate=3960watt hours.  You'll never get this because you aren't using them at the 20 hour rate.

Depends on the Peukert's exponent for your batteries but lets be generous and say real life you'll probably get maybe 40ah from them to 100% DOD at your discharge rate.  Now you don't want to take them to 100% DoD if you want more than 50 cycles out of them so lets say 80% which is still hard on them.  The omission of these factors I think is the main flaw with the El Ninja/ El Chopper calculations.,

Now we have 72v (lets ignore the real voltage sag for now) x (40*0.8)=2304 usable watt hours.

Now if you want to go 30 miles would would need to achieve 76.8 watt hours/ miles efficiency.  Near identical conversions are getting more like 120wh/m which would yield less than 20 miles which is at the high end of most conversions so good well done in my opinion, but if you expect 30 you will be disappointed.  I hate to say it, but on a stock aerodynamics bike, doing highway speeds breaking 20 miles range with lead in dam hard. 

That's why my next conversion is using NiCad.  I probably won't go any greater distance, but I should get better cycle life.

 

Lithium batteries has the whole ev community in waiting for the real breakthrough in energy density for what most would consider acceptable range.  The lead range does work for a lot of things though and it's want we can afford now and the drive-train doesn't care what batteries your using if it makes sense to change in the future.

 

-Garret

 

84 Honda VF500
[[[ My goal 60 mph, 30 mile range commuter ]]]

 

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