EV Miata at the SFEVA meeting

Today is the day.
I have had a string of target dates for getting the car done, but today is the day I promised to take it down to the SF Electric Vehicle Association meeting. The batteries aren't terribly balanced, but good enough for, say 98% state of charge (SOC). I made some progress on the gauges, but still no ammeter, tach or temperature gauge. I was going to hook up the Zilla's cooling system too, but that was not to be.

So, mostly charged and with just a speedo and SOC gauge, I was off.
As this was the first drive farther than around the block, I took my time and stuck to the streets. It wasn't too far, less than 5 miles I figured, so it should make it there and back easy - and it mostly did.

The SOC gauge drooped precariously each time I stepped on the juice (AKA the accelerator). Without the ammeter it was hard to drive it carefully, but I gave it my best. At about 4 blocks away the "Check Engine" light came on. The Zilla uses this to tell you that something is wrong, but I couldn't tell if the controller was overheating, the battery voltage was too low or something else was happening. I pulled over and checked the temperature of the controller using a manual temperature sensor - I stuck my hand on it - and it was just warm. The SOC gauge was showing 50% -which, because it only show the "usable" 50% of the pack, indicated the pack was at 75% SOC - not bad. The wiring under the hood looked fine and nothing smelled hot, so off I went. I found Luscious Garage (great place), where the meeting is held each week and pulled in to the drive. Dale, the president, and a few of the club members were out front around a RAV4 EV. After chatting a bit I broke out my palm to read the Zilla error code - d'oh, the SLI battery was low again! This is the same error that caused the car to limp up the street in the "It's Alive" video... Maybe I need to replace that battery...

Anyway, I got to talk a little about the project in the meeting and got to show my handy work off to some people who "got it" - very nice.

One of the long time members let me know that it takes about 3 cycles to get your pack "broken in." Good info.

After the meeting was over, I borrowed a Luscious charger to juice up my SLI battery. In hooking it up I found the negative clamp had worked it's way loose. So maybe the battery was still good? Maybe. At any rate, the Zilla error was soon cleared.

The SOC gauge was now showing 30% (65%) and I was off.
The SOC gauge which had earlier been bouncing about was now spending most of it's time staying around zero. Not good. The car ran well, though, no rattles or other strange noises, just the whine of the motor. Why do people want to play amplified gas car nosies in an EV?

I drove by a motorcycle club with a guy hanging our front. I think he was drinking out of a paper bag, but I could be wrong. Anyway, I pulled up the red light and stopped. Absolute silence.
He shouted "Why is your car making that whine?"
Me: "eh, it's electric."
Him: "Did you do that yourself?"
Me: Expecting now to be told I was a fool to spend a year and $13,ooo with gas prices now under $2, I simply answered, "Yup." and prayed the light would change.
Him: "Very cool."
Ah, this is nice. Even bad-boy bikers drinking out of a bag on the street corner appreciate an electric car conversion. Maybe things are changing...

Not too much longer down the road the "check engine" light makes a return appearance - and this time it's blinking. I recognize this as the Zilla trying to tell me my pack voltage is dangerously low. I pull off onto a side street and let the car sit while I try to act normal.
After what seems like 30 minutes, but was probably less than 10, the SOC is showing 10% and I'm off again. Slow-ly. I'm now less than 5 blocks from home and decide to go for it.

Once I get home I pop the hood and start reading voltages off the batteries: 12.06, 12.07, 12.11... About 40% SOC, not good.
One battery, #5, was showing 10.96 volts. That's not just dead, that's off the chart dead.
I gave it a little charge at 6 amps to bring it up into the 12 volt range and turned on the Zivan. Everything seemed fine, but, after about an hour, #5 was showing 15.5 volts, (15.6 is the limit) where the rest were all around 13+ volts. I turn off the Zivan and head upstairs.
That's enough for one day...