Friday, October 30, 2009

John's PakTrakr Display

I shipped the PakTrakr modules back to the owner (Ken Hall) for calibration. Ken mentioned that they were rebuilding their calibration unit and would send the modules back as soon as it was finished.

I also received an e-mail from John Barton who used the open-source Civic battery rack design as a starting point for his own lithium-ion battery racks for his Civic DelSol:

Hi Tim,

I'm finishing up my second ev conversion, this time its a '93 Honda del Sol. My blog is I'm also finishing a display for the paktrakr that runs on windows ce 5.0. I've got a basic version running on a GPS. Since you are using a paktrakr I thought you might like to give the display I wrote a try. Let me know if you are interested and I can send you an early version of the bits. I'll be blogging about it in a day or so.

The display I'm using is this:

Also it requires a serial to bluetooth adapter like the IOGEAR.

John Barton
It looks like he has a cool display that takes the PakTrakr output and shows in a user friendly format. I'm quite swamped these days, so I'll consider trying it out if things slow down this winter.

Looking forward to getting my PakTrakr back...

Friday, October 16, 2009

Installing the PakTrakr

I took some time to install the PakTrakr modules today. I was a bit disappointed in the voltage measurements from the PakTrakr remotes, so I'll probably send them back for recalibration. Here are the voltages I measured:

Unit #1

Battery # Battery(V) PakTrakr(V) Difference(mV)
1 13.43 13.5 70
2 13.49 13.7 210
3 13.48 13.4 -80
4 13.49 13.9 410
5 13.52 13.9 380
6 13.28 12.9 -380

Unit #2

Battery # Battery(V) PakTrakr(V) Difference(mV)
1 13.41 13.5 90
2 13.46 13.7 240
3 13.47 13.4 -70
4 13.46 13.7 240
5 13.5 13.7 200
6 13.29 13.5 210

Unit #2 isn't too far off, but batteries 4, 5 and 6 on unit #1 have too much error to accurately determine the state of the pack. I contacted Ken Hall at PakTrakr today for advice before I send the units back.

To help with air resistance, I might run to the plastics store and cover the entire front grille with a sheet of ABS plastic to see if that cuts down on the drag as well as the cooling effect on the front batteries...

Saturday, October 3, 2009

Range Anxiety

As you've probably noticed, things have been a bit quiet here. The new vacuum pump is working well and is nicely quiet.

As the temperatures drop, the capacity of my batteries drop as well. After almost a year of hard driving, I suspect the batteries are also losing capacity. Over the past week, I've been driving a gas car because I had long errands after work that would have exceeded the maximum range of the Civic-EV. The few times I did go into work, I ended up crawling along at five miles an hour for the last half-mile.

If I force myself to stay under 55 miles an hour at all times and use hypermiling techniques as much as possible, I don't lose power near the end of my commute, but as temperatures drop, I fear that I won't even be able to even get to work.

This is the classic problem with electric vehicles: range anxiety. I have plenty of power from the Warp9 motor, but the battery current and capacity just isn't enough for my commute anymore. I can't confidently drive on the freeways anymore because I might lose power after ten miles of pushing it past 60 mph. If I stop commuting with the electric vehicle, that takes away 90% of my driving, which makes owning the car somewhat pointless.

The first thing I'm going to do is install a PakTrakr monitor. This is something I should have done a year ago to accurately monitor each battery. The Link-10 E-meter is good, but doesn't monitor individual batteries. For all I know, I might just have one bad battery in the pack. I already have the PakTrakr on my bench, but I haven't had time to install it. I just might do that this weekend.

Some options to consider:
  • Purchase a whole new set of batteries for $3000 (ick!).
  • Spend a lot of time making the car aerodynamic like the Aero-Civic
  • Redo the system with lithium-ion batteries and double the amp-hours for $10,000 and lots of time (ouch!).
  • Sell the vehicle at cost minus the price for the batteries, go with an ICE and buy a Nissan Leaf when it comes out.
After installing the PakTrakr, I'm going to try and commute for a few more days in this colder weather to see if things still work. Perhaps I only need to replace one battery...