[EVDL List]

Tom S. wrote:
> Hi Everyone,
>
> The first test went like this, driving the Evette 30mph, with only a 120volt battery pack, the least amount of amps so far was 40amps. Thats with super swamper tires, and not much warm up time. I did the test with a 50mv 500amp shunt, and a multimeter. Let the math begin.
>

I'm probably going to regret jumping into this, but ...

How is this data useful? To get any meaningful idea of energy usage,
you need to know more than the minimum current draw at one particular
moment in time. Were you in a tailwind? Going down a slope? Simply
letting off a little on the throttle? Drafting behind another car?
Instantaneous readings tell us almost nothing about what the car is
doing, certainly without additional information.

Starter suggestion: pick a stretch of road, the longer the better (a
mile or two at least), and travel it at a given speed, and measure
amp-hours consumed on that pass. (You do have an e-meter or some kind of
amp-hour counter right?) Try again at a different speed. Keep a chart.
Make a modification to the car, and do it again.

If you don't use real methods of measurement (and I don't count myself
as an expert here), you'll never have more than wild guesses. That's
fine for a car you're building for yourself, but not if you're trying to
sell an idea.


--
Christopher Robison
[email protected]
http://ohmbre.org <-- 1999 Isuzu Hombre + Z2K + Warp13!

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[EVDL List]

Hi Christopher,

No tailwind, level road, even throttle, no drafting, one mile stretch of road. My good friend Steve Clunn, and I have been putting e-meters in cars for years. I wonder if he takes it to bed at night instead of his wife. Surely some math can be done without an e-meter. Right now I`m trying to make the car more efficient so I`m watching amps, however I hope to put an E-meter in the car soon. Tough crowd!

Tom Sines
-----Original Message-----
>From: Christopher Robison <[email protected]>
>Sent: Aug 17, 2007 11:10 AM
>To: Electric Vehicle Discussion List <[email protected]>
>Subject: Re: [EVDL] Electric evette amps
>
>

Tom S. wrote:
>> Hi Everyone,
>>
>> The first test went like this, driving the Evette 30mph, with only a 120volt battery pack, the least amount of amps so far was 40amps. Thats with super swamper tires, and not much warm up time. I did the test with a 50mv 500amp shunt, and a multimeter. Let the math begin.
>>
>
>I'm probably going to regret jumping into this, but ...
>
>How is this data useful? To get any meaningful idea of energy usage,
>you need to know more than the minimum current draw at one particular
>moment in time. Were you in a tailwind? Going down a slope? Simply
>letting off a little on the throttle? Drafting behind another car?
>Instantaneous readings tell us almost nothing about what the car is
>doing, certainly without additional information.
>
>Starter suggestion: pick a stretch of road, the longer the better (a
>mile or two at least), and travel it at a given speed, and measure
>amp-hours consumed on that pass. (You do have an e-meter or some kind of
>amp-hour counter right?) Try again at a different speed. Keep a chart.
>Make a modification to the car, and do it again.
>
>If you don't use real methods of measurement (and I don't count myself
>as an expert here), you'll never have more than wild guesses. That's
>fine for a car you're building for yourself, but not if you're trying to
>sell an idea.
>
>
>--
>Christopher Robison
>[email protected]
>http://ohmbre.org <-- 1999 Isuzu Hombre + Z2K + Warp13!
>
>_______________________________________________
>For subscription options, see
>http://lists.sjsu.edu/mailman/listinfo/ev


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