Tuesday, August 30, 2011

Final Parts List

Finally some news worth publishing!

The electric car is coming along, slowly but surely! After a couple months of planning, hundreds of emails, innumerable calculator buttons pressed, and buckets of tears and blood, the car has finally recieved its final parts list. Here she is:

  1. Zilla 2000 EHV -Ordered
  2. Warp 11" HV, custom modified by Dennis Berube, owner of the 'Current Eliminator'
  3. 1008 Headway 8ah 38120P battery cells
I know you must be in disbelief, how can picking 3 parts take two months? Well, it took a while to figure out which motor to get, and who to modify it for me. That said, the single most time consuming choice was undisputedly the battery pack. Not to mention, figuring out how to couple the engine to the transmission in direct drive. 

Crodriver battery pack

The pack will be run in 112 series / 9 parallel. This will allow for 375.2v, and 2000 amps at 28c. 
Theoretically, this pack would be able to release, 751Kw, which in gear head terms, is 1008 Hp. Unfortunately, we live in an imperfect world, and using a simple formula, it is easy to uncover the peak Hp after accounting for 'inefficiencies'. The battery pack should be able to release 551 Kw, aka 740 Hp. Not too shabby! To make good news a little worse, we will only be able to get about 500 hp out of the poor motor, which is running nearly double its recommended current. As each individual cell weighs 300g, the battery pack as a whole should weight 665 lbs. Painful, I know, however there isnt much I can do. The good news is that I expect an average battery usage of 250ish WhM^-1, so with almost 26kwh's of energy I should be able to travel 105ish miles on a charge!

I originally wanted to use a 16ah headway pack, however the impedance on each of the individual cells was too high (>8 milli-ohms). Then, I wanted to get A123 batteries from a so called 'reseller' of their batteries. In the end, the batteries would cost about $27k. Simply too much for me to afford. 

The good news is, according to similar cars, the s2000 should be able to zip down the street quickly, hitting 60mph in about 2.3 +/- 0.5 seconds from a stand still. Some may say I'm being optimistic, but my excitement inundates all outside errors. 

I am basing my battery packs construction on crodrivers battery pack, using plexiglass or 'sipas' to hold the assembly together. The only problem I am sure to encounter is in regard to the car's minuscule size and free space. The battery pack is going to contain 1009 cells, each of which have a size of 138cm^3.
So theoretically, I would need a cube with sides 52cm long to store all that juice, but once again, nothing ever works out the easy way (a reoccurring theme). I know for a fact, that I will need to separate batteries into the trunk and engine compartment. I do plan on installing a recessed area for the batteries in the trunk, however I don't really know what will happen in the engine compartment. 

Crodriver completed battery pack (10ah Headway, 108s/8p)

Until next time!

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