View Single Post
Old 05-28-2015, 12:08 PM   #2 (permalink)
Master EcoModder
Join Date: Sep 2010
Location: Saskatoon, canada
Posts: 1,474

ChargE (not yet running) - '92 Mazda MX6 LX
90 day: 33.89 mpg (US)

Ford Prefect - '18 Ford F150 XLT XTR
Thanks: 745
Thanked 541 Times in 436 Posts
Originally Posted by Thalass View Post
Unfortunately it seems my go-to spreadsheets and forum posts have vanished from the internet - and I've forgotten the general rules-of-thumb.
It happens!

has a CoD of 0.29, though my daily commute won't be fast enough for that to be a factor. I'm assuming 300Wh/km. My commute will be a tiny 10km each way, with a decent hill to climb on the way there but coasting downhill on the way home. I bodged up a spreadsheet which informs me that a range of 25km will require a 6kWh pack, 41.6Ah per cell with pack voltage of 144 (80%DoD). LiFePO4, of course. I think the most important thing is keeping up with traffic, for now. In the future I could buy another pack for longer range - ultimately my inlaws live about 150km away, and this is the furtherest I should ever have to go.
This calculator is dated, but the info still appears to apply. No new batteries are listed and the range is pessimistic with lithiums ... but besides that ..

EV Calculator

If you stay with a standard transmission, you can still cycle through the gears and keep up with traffic, even if your vehicle is a bit under powered.

I don't think you need to sacrifice power, unless you find a good deal on the motor or controller.

I still prefer AC motors on principle, but man they are still expensive!
If you are willing to wait for me to finish testing Paul's AC controller, that may be a lower-cost option for you.

For the initial conversion I'm willing to go with DC, and I would rather like to build a P&S controller myself. I guess I figure if I spread the cost over many years of tinkering my wife won't notice how much I've spent on what should eventually end up as an electric sports car :P
I'm not associated with EVTV, but I like their prices on this stuff:
- 100 A-h CALB SE - $95 each seems like a good deal to me, but they are no-warranty and a few years old stock EVTV Motor Verks Store: CALB SE100AHA 100Ah LiFePo4 Cell, Lithium Battery Cells, SE100AHA
- Siemens motor $3500 EVTV Motor Verks Store: 1 Siemens 1PV5135-4WS14 AC Induction Motor, Motors and Controllers, 1PV5135
- Siemens motor adapter $1000 EVTV Motor Verks Store: Siemens B-Face Adapter, Drive Train Components, bfaceadapter

It's the least expensive AC option I've found so far ...

Anyway, have I forgotten anything? Am I being too optimistic? 45 CALB 400Ah cells should cost $2430 before shippping (probably US$, too). By comparison 45 260Ah Voltronix cells would give me enough range to get to my inlaws' house but would cost $15210!
You likely know this already, but you did not mention:
- DC/DC converter or 12V pack of LiFePO4 to run accessories
- heater to keep the windshield clear when it's raining. Water heat to use the existing controls in the car or PTC heater cores installed in the ducts to run direct off the pack
- charger is normally expensive
- do you need a power steering pump or a vacuum pump for the brakes?
- fuses and fuse holders are expensive
- you did not mention instrumentation for the pack, voltage and current, maybe amp-hours, perhaps temperature?
  Reply With Quote