View Single Post
Old 09-28-2014, 09:27 PM   #35 (permalink)
Join Date: Nov 2013
Location: Australia
Posts: 350
Thanks: 95
Thanked 210 Times in 150 Posts
Originally Posted by thingstodo View Post
Wow - you seem to have a strong handle on what everything weighs and what battery capacity you need.

What does you car weigh and what are you projecting for w-h/km or w-h/mile? Does that include some 'fun' driving?
Fun driving has been one of the main requirements from the beginning.

I have a spreadsheet i used to calculate everything right at the beginning of the project. It uses logged GPS data to calculate power usage taking into account such things as the rolling resistance, wind resistance, conversion efficiency, weight, terrain etc.
When i went to get some figures for you i noticed they all seemed a bit off.
I dug down into the formulas and found a fudge figure.
Looks like this figure is used to tune the result to match real world. But that makes it not very accurate as a prediction tool prior to the build.
I didn't notice this in the beginning as i didn't know enough to feel that the figures were not quite right.
So i will have to rewrite the formulas to reduce the need for the fudge figure.
My battery requirements may need some revision.
  Reply With Quote
The Following User Says Thank You to Astro For This Useful Post:
thingstodo (09-29-2014)