Prototype Controller Testing Part 2

Last week we tried out the "ReVolt" open-source controller for the first time.  At the time, we only had one MOSFET and diode installed.  We were able to spin the small motor at 12V, but when we tried the kart motor at 48V, something popped so we stopped for the evening. This week, with some modifications and a more cautious approach, we were ready to try it again.

Cause of Last Week's "Failure"

First, some commentary on what went wrong last week.  When Bill took apart the power section, he really could not find anything wrong.  At the time we thought that perhaps there was a current spike through the diode as we applied power to the big motor.  But now we think that maybe it was the silver epoxy.  Perhaps there was a high resistance path somewhere that overheated when we started to flow some real current through it.

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Battery Experimentation Part 1

We want to better understand how these LiFePO4 batteries work, so I ordered 4 small hobby cells.  These are the same chemistry and cell voltage as the big battery cells that will make up the truck battery pack, so I think it is reasonable to study these to learn how the big battery will work.

I ordered 4 1300 mAh cells.  These are not expensive at all.  I also ordered a 4-cell charger which was a little pricey but I want to get straight to studying the battery characteristics,

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Prototype Controller Testing Part 1

Controller board and parts
Controller board and parts

This post summarizes everything that has been going on the past several weeks.  First, I ordered "Paul & Sabrina's" ReVolt open-source controller board.  Thanks Paul & Sabrina for making this available!  I ordered just the board, not the whole kit.  I ordered the components from Mouser and Digikey.  Insead of using the Atmel microcontroller they specified, I am using a Stellaris evaluation board.  Here is a photo of the blank controller board, the bags of parts and the Stellaris evaluation board.

And here is a photo of the board after most of the parts have been installed.

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Some Preliminary Decisions

Date By joe Category misc Comments 1

We have been spending the last few weeks collecting a lot of information about motors, controllers, batteries, etc.  We have all been getting a quick education in these topics.  But up to now we have not really made any solid decisions about how to do this conversion.

There are so many things to decide on when you start looking at what is involved in the conversion.  AC or DC system?  Once you decide that, which specific motor?  What kind of battery technology?  Which batteries?  Motor controller, charger ... it goes on and on.

I want to nail down some of these decisions so we can start making some progress on solving specific problems.  So here is what we have decided so far:

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The Conversion Vehicle

Date By joe Category Truck Comments 4

My 1993 Mazda B2600 - The conversion candidate
My 1993 Mazda B2600 - The conversion candidate

Here it is.  This is my 1993 Mazda B2600 pickup.  This is the last year that Mazda actually made these trucks.  After '93, the Mazda B-series trucks were just relabeled Ford Rangers.

  • Original owner
  • Approx. 110,000 miles
  • 2.6 liter, 4-cylinder
  • 5-speed manual
  • Rear wheel drive
  • Extended cab
  • A/C, power assist steering and brakes
  • (A/C currently broken - expensive to repair)
  • Curb weight: 3430 lbs
  • Gross vehicle weight: 4585 lbs
  • Fuel tank: approx 11.5 gallons
  • MPG: 19-22 city, 24+ hwy
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In the Beginning

Date By joe Category misc Comments 0

I have been thinking about doing an electric conversion on my truck for several years.  Especially when the price of fuel started to go up.  However, I thought it would be too much work and could end up being one of those kind of projects that I start and never finish.  Plus, while I feel I have a good understanding of how the system works, I don't have any fabrication skills to do things like welding brackets, etc.  My background is in electronics and embedded software.

I have also been greatly frustrated by the poor fuel mileage of the vehicles available

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