#2 is out, service disconnect is in

I was not looking forward to pulling out the number two battery. It has been not holding a charge and keeping the pack from getting fully charged, so it's got to go.

I had to remove the Zivan (you can see it upside down in the upper left of the pic.), a bunch of high voltage cables, the high voltage box and it's wiring and the bracket that hold all this in place.

Once all of that was out of the way, the battery was pretty easy to pull out and set aside.


Once the battery was out I started on my next project - installing the service disconnect. The idea is be able to disconnect the battery pack from the driver seat to make it easy to service the car or in case of an accident. Some people call these "emergency disconnect" switches, but I like the "service disconnect" name - why not put a positive spin on it?

There are three ways to do this
1. run high voltage wires under the dash to a breaker or switch.
2. put a low voltage switch on the dash to open a contactor
3. install a mechanical cable that activates a breaker under the hood.

Though I had originally planned on using option 1 and placing the breaker under the dash, I realized the high voltage cables really don't belong under there. I went with the 3rd option as it was the simplest, least expensive and safest (compared to #1).

I bought a choke cable at Kragen for around $5. I mounted the "pull" side on the tunnel near the bottom of the dash. This position provided the most room for my big feet...

I needed to mount the cable below the breaker. I ended up bolting an angle iron to one of the top rack's mounts. The cable itself was looped through a hole in the breaker's lever. The cable then looped together where a cable clamp to hold it in place.

It works good. It doesn't take much of a pull to pop the breaker, and just a little push to reconnect the pack. The breaker is spring loaded and does most of the work.

Survey says!

I've gotten a number of questions about providing a conversion kit for the Miata so back in August of last year I posted a survey to determine what kind of kit people were interested in. The link was on all pages of the main www.evmiata.com site and asked you to vote for the components, battery and kit type that you'd like to see.

The choices were:

components

• 156v WarP/Zilla
• 144v WarP/Curtis
• 144v WarP/Belktronix
• 144v Selectria

Batteries

• AGM
• Lithium
• Flooded lead acid

Kit Type

• Basic - Battery racks, brackets, motor mount and adapter
• Standard - all the above plus motor charger, controller and associated parts
• Complete - all the above plus bolts, cable ties and pre-terminated cables

The results were pretty impressive:

• 405 total surveys taken
• 180 votes (45%) went with the 156v WarP/Zilla route
• 29 votes (7%) went with the 144v WarP/Curtis route
• 57 votes (14%) went with the 144v WarP/Belktronix route
• 137 votes (34%) went with the 144v Solectria route

Of those voting for the 156v WarP/Zilla...

• 102 votes (57%) were for AGM
• 65 votes (36%) were for Lithium
• 13 votes (7%) were for Flooded

And for those voting for 156v WarP/Zilla with AGM...

• 27 votes (26%) were for Basic kits
  
• 26 votes (25%) were for Standard kits
  
• 49 votes (48%) were for Complete kits
  

So, as they say in politics, the people have spoken.
I'm closing down the survey today.

Thanks to all of you who participated in the survey!

The Battery Story

I realized that the battery problems I've been having may not make a lot of sense unless you know the full story - so I thought I'd give you all a recap and some lessons learned so that you may avoid learning them like me.

I had 13 Optima D34M Blue tops delivered before I was ready for them to be installed. This wasn't a bad thing, in itself...
You are supposed to test the motor when it's first installed to confirm that the flywheel, clutch and the motor all all in working order. I put the car in neutral and since the batteries were there, I jumpered one of them to the motor leads. It worked fine, but I put a drain on one of the batteries and now they were no longer balanced.

Lesson #1 - use your starting battery for this test - not one of your pack batteries.

Next was a little mishap I had wiring up the batteries. The details are in a post called "the meltdown", but the end result was 5 batteries were shorted out with one of them taking the brunt of the damage. One was replaced (it was the original #4) but the others are still in the pack and now out of balance with the rest of the pack.

Lesson #2 - don't be a numskull and short out your pack - or, more correctly, don't leave loose ends of cables on your batteries. Each cable should have both ends connected before you move on to the next. Don't leave one end unterminated while you go onto the next cable.

With the pack out of balance, I began to charge each battery individually. This is the way to do it, but you should use an automatic battery charger with an AGM setting. I used a manual charger, and though it worked most of the time just fine... well you get the picture.

Lesson #3 - invest in an automatic battery charger with an AGM setting for individual charging.


I have heard people say that Optima doesn't have the best quality control and that one should expect a battery or two to fail in a pack, and I can say the 2 that have been troublesome so far (#5 and #2) were not overcharged by the manual charger. But, if I had not put the pack so far out of balance I don't believe I would still be dealing with battery issues today.
And that, I think, that is the big lesson.

Pressed into service

My wife called me at work yesterday to say her car broke. She wasn't too far from home when something went ding (her words) and her battery light came on, then her power steering was gone and then it started to overheat.
Any guesses?
Fan belt, maybe?
I got home at looked under the hood and the belt was there, and in one piece, but it was all wrapped up - looks like an idler pulley broke off.
It was 6:30 at night and I took the Miata down to Kragen for some ICE parts.
Kinda ironic, I guess...
I didn't have a chance to put them in that night, so the Miata got to run errands and drop our daughter off at school. She enjoyed riding in it, not because it's quiet or quick or emission free, but because she can sit in the front. Anyway these little trips confirmed my verdict on #2 - she's bad. So replacing her will be my project for the weekend.
Since I will have everything stripped down up front to pull the battery, I invited the draftsperson (do they still go by that?) over to start the drawings for the kit. Might as well take advantage of the situation...
I also might install the emergency disconnect cable. I bought a choke cable that I was going to connect to the main circuit breaker so that I could disconnect the pack from the driver seat. It's been sitting on the toolbench. Maybe I'll have a chance to connect it this weekend too.

Sunday driver

Friday and Saturday I charged batteries - in between running errands and watching kids. But the pack is charged - though #2 is still acting a little flaky. I noticed that the pack looses voltage over time and am starting to suspect the Zivan may be putting a slight load on it. I've been leaving it unplugged from the pack to test my theory.

So around 2:00 Today the pack was fairly charged. My SOC gauge showed 95% which is closer to 98% in the real world, so I'm off. First thing I noticed in that the vacuum pump isn't working, but no matter, I'll just stand on the brakes like we used to do in the old days. I still have the tach set to display amps, and what a difference that makes in your driving style - you can't help but accelerate slowly and coast into intersections. They need to put something like it on gas cars - like an MPG gauge. Didn't make any friends with the other drivers, though. I took a mile and a half loop and came back to the garage to check things out. #2 is at 12.35v where the rest of the pack is in the high 12.4 to 12.5. I plugged the Zivan in and gave it some juice, but #2 came up to 15.6v pretty fast - the rest of the pack was in the 14v range when I had to abort the charge to save #2 from being overcharged.

I'm thinking #2 needs to go.

I let her rest for a bit then took her out for another drive. This was about a 3 mile loop (the trip odometer isn't working - gotta add that to my list). I took some streets with bike lanes and it sure confused the cyclists having a silent car running with them. I came back home with about a 70% SOC - not too bad. #2 was the lowest about a tenth of a volt below the rest of the pack, and again I had to abort the charge when #2 reached 15.6v.

#2 is in the most in accessible place in the pack - in the front of the nose rack on the driver side. I'll need to pull out the Zivan, all the high voltage cables to the box, pull the gauge, contactor and relay connections remove the high voltage box and bracket, then pull out #1 so that I can get to #2! It's gonna take me a full day just to get her out.

New #5

Today the replacement for the bad battery, #5 arrived. It was delivered to my door, no charge. Can't complain about that. I've been charging the rest of the pack up so that I can do some road testing with a good pack. Hopefully tomorrow I'll be on the road with 100% SOC.

Running out of things to do...

That sounds good doesn't it?
Today I went through my "Todo" list I made over the break...

#1 - Bleed clutch. I bled the clutch once before, but it still wasn't working. This isn't that bad in an EV, since there isn't much shifting involved, but I will definitely need a clutch to get my 0-60 time. I have a self bleeder kit (a plastic bag and a hose) so, once I took battery #6 out and cold see the clutch cylinder, it took maybe 10 minutes.

#2 - fix leaky (heater) hose. I'm using the heater core as a radiator/reservoir for the Zilla. Only problem is, I didn't plan for this and bent up the metal end when I pulled the engine. I spent 15 minutes making the leaky one rounder so that the hose clamp would seal.

#3 - Pull 12v lead to temp gauge. Before the break I troubleshooted the temperature gauge and found out my 12v supply wasn't working. I pulled a new wire from the fuse box to the instrument panel and wired it up.

#4 - Fix Tach. The tach hasn't worked and I've been suspicious of the sending unit. It is a magnet thing that looks like a plastic cup that is supposed to fit on the nose of the motor. Mine didn't exactly fit, so i added some washers to the mount so that it would. It's buried under Zivan, so fixing it is going to be tough... First thing they teach you in mechanic school (I'm told) is to start with the easy stuff, and work up to the hard. The easy thing is to see if some knucklehead mis-wired it at the hairball. Yup. White and Red were reversed. To test it out, I'll need to put the batteries back in and cable them up. Easier said then done, but they're in and I left the handle on #5 so I can easily pull her out later. I turned the key on, step on the throttle and the tach needle starts to wobble up the gauge - nice!

#5 Fix ammeter. Like the Tach, the ammeter has never worked, but I was on a roll. I started by setting my meter to millivolts and connecting it to the shunt (this is hidden in the high voltage box). I'm not sure what it's supposed to read, but the shunt is rated at 50 mv, so I'm guessing it should show 0-50 mv on the meter. I put the meter where I could see it from the driver seat and gave her some juice. The meter showed 7, 11, then 17 mv, which was enough for me. I then did the same test on the wires at the instrument panel with the same result. Hmmmm. Maybe the ammeter is bad? I decided there were 3 possibilities

1. Wrong shunt. But they only come in 24, 50 and 100 mv, so I would think the gauge would still read something, even if the shunt was the wrong value...
2. One or both Leads fell off the ammeter, I pulled out the panel and removed the ammeter - all were connected and even did a continuity test on the leads to double check my crimping was good.
   
3. Defective gauge. I read the instructions from Westach, but there were no trouble shooting tips other than reversing the polarity if the needle goes the wrong way, but my needle never moves. I'll email them to see if there is another test...

The Zilla has a setting to display amps on the Tach. Later, when I had the gauges back in I tried it out. Works pretty good. The Zilla manual says tach shows the amps x 10.

#6 Fix light in temperature gauge. The light stopped working in the temp gauge, and since I has the panel out I removed it and found the light had slipped half way out of the gauge. That was easy. While I was at it, this gauge never fit in right, so I spent some time adjusting the mounting clamp so that it didn't hit anything in the panel. Fits nice now - no squeezing and cussing needed...

Now I was seriously running out of things to do while the batteries charge...
I decided to fix the driver side courtesy light. Some adjustments and contact cleaner and she works!
This is getting bad...

#7 Fix remote charge indicator. As you might remember, I put a charge indicator in the charge port (where the gas used to go) so you could easily monitor your charge without popping the hood. I had to extend the cable to get it to reach and it does light, but I noticed the LED blinked red when it should be blinking yellow... maybe a short? I'm hoping it's not the splice I did, if it is, then I got to pull the wiring out of the conduit under the car to fix it.
Starting with the easy stuff, I pull out the LED from the housing to check my soldering job. Well, the wires got all twisted up in the housing and shorted out. A little electrical tape should do the trick... I'm still charging the batteries individually, so I can't test it out yet, but I'm going to call it fixed just the same.

Back to the batteries...
I had charged up all the batteries up front before using the motor to test the ammeter and the tach. When I checked them with the meter, they were down around 12.6 where they had been above 12.8. One, #2, was at 12.45! That's a pretty substantial drop for not even driving the car.
I check the trunk rack and they were all around 12.8. Is it my bad #5 battery dragging down the batteries in the front racks? Or do I have more bad batteries? I have been suspicious of #2, maybe she's gone bad too? If I had the money, I would replace the whole lot of 'em.
We'll see what happens after #5 is replaced.

Happy New Year!

I'm back.
and am anxious to finish this project. There isn't a lot left to do, just a few little things that need to be done...

First, the batteries. For the most part, they held their charge pretty well over the last 2 weeks. I still have the one bad battery, number 5, that needs to be replaced, but while I'm waiting, I'll charge up her sisters...

The only really new thing I have on my list is the fuse box. I originally had the Zilla and the vacuum pump wired to the same circuit. Later I added the Iota relay (so that it was only active when the key was on) to the same circuit and realized this was getting to be a bad thing. If the pump or relay blew, or shorted out for whatever reason, the Zilla would too. I bought a cheap fuse box on eBay before the break and today, mounted it on the firewall and wired it up.

While I was messing with the wiring I decided to tackle my wiring harness that snakes around the nose rack. It had gotten pretty messy from adding and moving wires after I had tie wrapped it all down and it's been bothering me. In case it's not clear enough from that comment, I have a *thing* about wires - OCD. It started when I worked at the phone company. Anyway, I had to disconnect a lot of the wiring and one cable, but after an hour and a half, it was nice and clean - no wires wrapped around each other and all covered in the wiring loom.