KarenRei
04-02-2008, 02:51 PM
I'm thinking about making a website that does in-depth financial calculations for people considering replacing their gas vehicles with EVs (or who simply want to know how much a particular vehicle would cost them). I'm looking for design ideas, particularly on the issue of maintenance.
How should maintenance be modelled? Should there be a flat number that the user has to guestimate that's used for every year? Should there be a number that the user guestimates that then gets adjusted according to some curve as the car ages, and if so, what curve? Should I go in-depth on maintenance, enumerating all significant parts that could fail and at what rate/with what probability (user-customizable for their particular vehicle, of course, probably with presets for particular vehicles), and then use that to calculate a flat rate that's used for every year? Or adjust that rate by a hard-coded curve, as above? Or actually simulate failures of each type of part along a Poisson distribution, to get the proper curve mathematically? And if we are including every significant part that could fail, would anyone here be willing to help with estimates on how much different vehicle parts cost and what their mean time to failure is? Hmm, if we did enumerate parts, I'd also need data on typical warranties for given parts and both the part cost and labor costs (perhaps labor should be listed by time, and then we could let the user set a per-hour cost for labor so all labor costs can be adjusted together).
This has been the main stumbling block holding me back from making such a calculator. A while back, I made one for solar -- see here:
http://www.daughtersoftiresias.org/progs/insolation/
As far as I know, It's by far the most in-depth solar calculator on the net. The part I found most essential is that it doesn't just give you payback periods, but actually takes into account rate of return and mortgage length at any given interest rate, as well as inflation and so forth. I'd love to do something like this for EVs and gasoline vehicles, if only I could find a fair way to tackle maintenance. Raw guestimates of overall maintenance costs seem like a very poor thing to use in a calculator, but I don't have the data for how much different car parts cost or how long they last.
How should maintenance be modelled? Should there be a flat number that the user has to guestimate that's used for every year? Should there be a number that the user guestimates that then gets adjusted according to some curve as the car ages, and if so, what curve? Should I go in-depth on maintenance, enumerating all significant parts that could fail and at what rate/with what probability (user-customizable for their particular vehicle, of course, probably with presets for particular vehicles), and then use that to calculate a flat rate that's used for every year? Or adjust that rate by a hard-coded curve, as above? Or actually simulate failures of each type of part along a Poisson distribution, to get the proper curve mathematically? And if we are including every significant part that could fail, would anyone here be willing to help with estimates on how much different vehicle parts cost and what their mean time to failure is? Hmm, if we did enumerate parts, I'd also need data on typical warranties for given parts and both the part cost and labor costs (perhaps labor should be listed by time, and then we could let the user set a per-hour cost for labor so all labor costs can be adjusted together).
This has been the main stumbling block holding me back from making such a calculator. A while back, I made one for solar -- see here:
http://www.daughtersoftiresias.org/progs/insolation/
As far as I know, It's by far the most in-depth solar calculator on the net. The part I found most essential is that it doesn't just give you payback periods, but actually takes into account rate of return and mortgage length at any given interest rate, as well as inflation and so forth. I'd love to do something like this for EVs and gasoline vehicles, if only I could find a fair way to tackle maintenance. Raw guestimates of overall maintenance costs seem like a very poor thing to use in a calculator, but I don't have the data for how much different car parts cost or how long they last.