We Have Locomotion!

Pulling out of garage on electric power

Yahoo! It works!  After carefully charging the battery pack and working out a number of bugs in the setup of the battery management system (BMS), I decided it was time to take the truck out for a quick spin around the neighborhood.  What a thrill--nothing blew up, nothing caught fire, nothing shorted out.  I had a scare for a few moments when there was a weird whirring noise which didn't stop when the vehicle did, but I quickly realized it was the vacuum pump for the power brakes--it's working properly too, yeah!  

EV in the neighborhood

The drive was really short, just up the block and back twice.  I had no hood, no lights, no bed, laptop on the seat next to me logging data.  Didn't want to go too far.  It was cool and weird to be driving an making no noise except tire noise.  I think I'm going to like this. 

A happy EV driver

The purpose of this test drive, in addition to see if it worked at all, was to determine if my sensors on the drive side of the system were working.  I had some indication that my current pickup on the discharge side of the battery system wasn't working correctly.  I found out that was true, so now I've got to troubleshoot that.  Without this current pickup I can't tell how much of the charge I've used up--in other words I'd be driving around without a fuel gauge.  There's a long list of stuff that needs to get done before I can have a working EV, including:

• Fixing the current pickup on the discharge side
• Testing the controls on the discharge side to ensure the system shuts down when batteries are empty
• Fixing the short in the heater
• Making and installing battery and motor controller covers
• Bleeding the brakes
• Putting the dashboard back in and installing the new gauges
• Putting the hood back on
• Reinstalling the bed with a hinge and lift system

The end-of-academic-term crunch is here so I'm not sure if I can get all of this stuff done before the Christmas holiday.  Now that I think about it, working on my EV over the holidays would be a really nice present.

Ooh, Ooh, It's Nearly Running

All wired up and no place to go

Battery pack with BMS chips installed

I spent a bunch of time over the last two weeks finishing up all the wiring for the battery packs, motor controller and the BMS (battery management system).  It's all up and running now.  I turned the whole system on--relays clicked, inverters hummed and nothing started burning--whew.  In spite of my careful checking and double checking of the wiring, I still was a bit worried when I flipped the breaker for my battery pack.

Brains of the BMS wired up

Theoretically, I could open the garage door, turn on the key and drive the truck out into the street today.  It would be slightly less than street legal since it currently has no hood, bed, tail lights, or license plates installed (minor little details).  However, that's not what's stopping from taking a quick emissions free spin around the block.  Before I actually power up the electric motor, I need to program the BMS, charge the batteries and make sure the system is working properly.  Failure to do this correctly could result in damaging the $8000 battery pack.  So I'm now working on programming the BMS. I was successful in getting the BMS powered up and connecting to it's computer via my laptop.  Unfortunately that was the limit of my success this last week.

We're engineers, let's be obtuse!

Snapshot of BMS data

I'm an engineer (civil engineer not electrical or mechanical) and I hate it when engineers write a technical document that can only be understood by the engineer who wrote it.  The BMS "manual" at the Elithion web site is just such a document.  I think most of the information I need is on this site, but it's not easy to find and when I find it it's often a very broad instruction that you can't complete without more information, or there's a ton of detailed information but no specific instructions on how to complete the task.  

Here's one of my favorite examples.  The setup page of the instruction manual tells you that "Many other parameters may be customized, but usually they are left to their default" with no further information on how to determine what you need to change and what you can leave at it's default setting.  One group of "other parameters" that you have to set are the information that the BMS uses to determine the state of charge, i.e. how full your batteries are at any point in time.  If you hunt around long enough you'll find two other pages, each tens of screens long, that I think may have the information I need to set these parameters.  It will take several hours of deciphering and a few phone calls to be sure.  

The Elithion BMS is definitely not a Mac.  It's a long way from plug-n-play and the company seems to like it that way. I've read a few posts by one of the Elithion engineers on several EV forums.  These guys are a lot like bad IT support folks.  They're way smarter than their customers about how their product works--duh--and they pride themselves in pointing out just how stupid their customers are--not a good way to get new customers.