Brackets on the motor rack

Got a chance to do some welding today and went after the brackets for the motor (cowl) rack. I decided to offset it to the passenger side so that it could be as close to the cowl as possible (making room for the brake booster). This also will give me a good location to mount the Zilla - just ahead of the booster. The front brackets weren't very tricky, but the rear ones had to be angled to align with some existing holes in the frame rail. The one on the passenger side had to sneak under 2 brake lines also, so it is angled and shaved on the top.

At any rate, the holes all line up and the welds look good. Next is to weld some tabs on the driver side to attach a bracket for the Zilla and on the passenger side to attach the Iota.

Oh, you might notice a little green box behind the rack. It is the Zilla's "hairball" (its wiring box). I screwed it to the firewall a week ago. After I get everything mounted I'll get started on the wiring.

Charger quandry

I was about to order the Manzanita Micro PFC-20 I planned to use when I found out some bad news. First, the price has gone up around $300, second, there is now an 8 week wait for delivery and lastly, it appears you can't get the battery regulators that are made to work with it.
The battery regulators are needed for the AGM batteries I'm using to keep them from being damaged from overcharging since they can't "off-gas" like old school flooded cells.

I spent some time researching the battery regulator options and found PowerCheq and BEQ1.

The PowerCheqs sight says they may not work with long battery strings. I contacted Ryan at EVSource who sells them to see if they would work with my 13 bat string. Ryan replied that he didn't recommend them, and haven't got a reply when I asked for the reasons why.

BEQ1s looked good and were designed to work with the Optima D34M batteries I'm using, plus they are $20 less than the PowerCheqs. I contacted the manufacturer of the BEQ1s to see if they would work with the PFC-20 and the answer was no - they only work with the Zivan NG3. I had looked at the Zivan, but they are not dual voltage like the PFC-20, so I would need two chargers - one for 220 at home and another for 110 opportunity charging while on the road.
The Zivan is smaller and cheaper than the PFC-20, so it's worth looking into, and maybe I can come up with a cheap way to handle 110 charging...


I checked around and found a step up transformer that says it can step up a 15 amp 110 circuit to 220, but doesn't give an amp rating for the 220, but it's less than $100. I sent the Zivan folks a message to see if they thought this idea would work. Their reply was to say the NG3 charger needed more amps than the charger would offer and that they would get back to me with a proposed solution.

Maybe I need to get a cheap Rusco for the 110 charging and mount the Zivan in the garage?

So, I guess I'll wait to find out what the folks at Zivan come up with...

SFEVA meeting thoughts

The August San Francisco EV club meeting was focused on conversions, and Dale Miller asked me to talk about this project. I was pretty honored to be invited - it was only 2 years ago that I knew nothing and now I'm being asked to play expert. Luckily Lawrence Rhodes (who I knew from his postings on a number of EV discussion lists) was there to keep me honest. There were a surprising number of really good questions from the group - obviously a lot of people there were seriously considering a conversion and were deep into the research phase.
During the introductions someone mentioned they were doing 2 AC 914 conversion . I should have made a mental note of this, but instead rambled through why I didn't choose a 914 or an AC conversion and later realized that since I was in the role of an expert, I might have offended him. If so, I apologize.
But what I did want to mention here in the blog was some details around the Miata's specs. One of the questions that came up was around the curb weight of the first generation Miata. I, of course, being unprepared gave an answer I thought was right, but was, in a word, wrong. I have since looked it up and found the Gross Vehicle Weight is 2700 lbs. (on the door jam sticker) and the curb weight is listed on edmunds.com at 2116 lbs. So what does this mean? The curb weight is the weight of the car with fluids and a full tank of gas. I believe in 1999 the government also wanted to include the driver weight of 150 lbs, but this is a '92, so no driver is included in that 2116 lb. figure. The Gross Vehicle Weight (GVW) adds the weight of a driver, passenger and cargo and is intended to represent the maximum weight the car is designed to carry. I have heard some EV conversion shops talk about not exceeding the GVW in your finished EV, or you might have structural problems. Of course, those can be mitigated by strengthening the car's frame, but it's still a good rule of thumb.
The other question that was a stumper was on Miata's aerodynamics. I like to say the Miata has good aerodynamics, but when asked for the figure, I drew a blank. I had to look this up again, and found a listing on Wikicars.org that said " The body was reasonably aerodynamic, with a Cd figure of 0.38." Now .38 isn't particularly good, but it's better than a Triumph Spitfire, but not quite as good as a '99 Mustang (http://en.wikipedia.org/wiki/Automobile_drag_coefficients). I suspect that a modification or two (like a belly pan) might improve this substantially. I guess I'll try to say the Miata has OK aerodynamics...
So thanks agian to Dale for inviting me and the attendees for putting up with my rambling talk. Hopefully someone got something out of it, and don't forget to question authority.

Lots of parts - web site update

Got back from vacation and found a little time to update the web site. I fixed a typo in the budget that brought the project cost down a bit, added a FAQ page based on some of the email I've gotten and added a link page that lists a bunch of Miata conversions on the web - with a snarky comment or two.
Also, while I was out I ordered a few bits and pieces, so I should have the cable, lugs, terminals, shrink wrap, fuse holder, etc. - enough stuff to keep me busy a while. Take a gander at that circuit breaker - it's like 8" tall!
Maybe I'll get some time this weekend to work on the car...

Chop and section?

So I was all set today to weld on the brackets to the motor/cowl rack so I could get it grind-ed/painted/bolted in like the other two.
But there was a problem...
I noticed that the edge of the rack was right over one of the motor terminals.
The terminal will have a rubber boot on it, but it will be carrying 156 volts, and if it were to contact the rack it would dump that 156 volts to the body of the car.
Yes, it's not very likely to happen, but the rack is a little wider than it needs to be, and I think I'd feel a little safer if it wasn't directly over that terminal.
So outcomes the sawzall.
It wasn't as easy to cut through the welds as I thought it would be - they must be stronger than I thought.
Comes out the rack was an 1 1/8" too wide. Now it will be nice and snug around those batteries.
he picture are awful (still using my daughter's $10 digital camera), but you can see the before and after shots of the terminal next to the rack.
I'll have to get those brackets on next time...

Steak night!

Today is paint day.
After making the battery hold downs for the front rack and bolting them in place, I ground down the welds on both the nose and trunk racks.
where the grinder couldn't reach, I used an emery cloth or a file.
Looks pretty clean, not perfect, by any means, but pretty good.
next it was a trip to the back yard for a coat of primer. It was fairly warm and not much wind, so the painting went well.
after the primer dried inside and out, a broke out the stock red miata touch up paint.
I figure if I painted the racks the same color as the car, it would look stock-ish.
The shiny paint brought out all the imperfections in the racks. Good thing most of it will be hidden by the batteries!
So much for show car quality...
Once I got them in place I bolted them in for real - and they looked awesome.

It'll be steak tonight!

Some reworking of the nose rack

Well, it occurred to me that the proper way to hold down the rear of the nose rack is to break the rack in two. Figuratively, of course. The idea is to make the rear brackets into a separate piece with a length of steel connecting them together across the engine compartment. This will make the rack easily drop into place and then bolt up to the bracket piece.
Simple enough?
So I cut off the rear brackets leaving enough on the rack to allow it to bolt up to the new piece.
I then ground the brackets I removed into shape (had to replace one since it was a little short and a bit ugly). I then measured out, cut and welded in a length of flat 1 1/4" steel.
The rack slides in real nice now - no banging and cursing the headlight assemblies, and no fear of damaging the headlight wiring.
I drilled three holes to mount the rack to the bracket piece - one on each side and one right down the middle.
I then welded on the tabs to the rack that will connect the battery hold down straps (these are the steel strips that run across the top of the batteries so that they don't pop out on a big bump (or when the car flips over)).
There wasn't room for the tabs to go horizontal in the front (the rack wouldn't fit) so the front ones are vertical and the rear ones are horizontal. I welded the rear ones on a little high so that the rack could used them to rest on top of the "bracket bar"
Much better