Thursday, 11 October 2012

The Plan

The first thing the ebook I bought said to do was plan. I don't have a donor vehicle yet, I am going to trawl trade me to see what I can find, and what I like, after I work out what my modifications will weigh!

So the requirements for my Waiheke EV.


The highest speed limit on the island is 70km/h, and that's only on one 3km stretch of road. The rest of the island is 50km/h. So speed is not a big concern. I don't therefore need a high voltage motor, so I can keep my costs down. A 144v motor set up could get my car to 130km/h, but when will I need that?

However, there are lots of hills on the island. So when EV secrets tells me that a 48v motor can get my car to 50km/h, I think that would be less on a hilly island.

So: I think I will design myself a 96v or even a 72v system.
(an electric motor)


The island is small. after looking it up on google maps

View Larger Map

There's really no need for me to have a range of more than 30km.


So, with a range requirement of only 30km, if i were to use Lead Acid batteries I would need to install a battery capacity of 60km, as those batteries do not like to get below 50% charge.
Lead Acid Battery

If I were to use the Lithium Iron Phosphate batteries, I would need only to build a 40km range, as these can discharge down to 20%. These are however much more expensive. yet lighter. the trade off.
a funky LiFePO4 battery pack

The donor car

this is an important decison, and one I can make only once I've decided on the other parts, because the gross vehicle weight of the car once all the parts are in (and the passengers) cannot be exceeded.

What will I choose?

It must be:

  • no rust!
  • light, with a GVM able to hold the weight of the batteries.
  • no power steering or air conditioning!
  • looks nice
  • of a make where an adaptor plate already exists (Ideally)

Once I have the donor car sitting in front of my house, then I'll feel like I'm truly on my way.

Please share your thoughts.

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