[kerrymann]

Since I am still waiting for my motor adapter I have been doing some work on the battery pack. I have tested the 8 cells I received and found the capacity ranged from 17.2ah to over 19.2ah. Not very good for building a balanced pack. I contacted the seller but have yet to hear back. We'll see what happens but this is exactly why I ordered 8 first instead of jumping in to the full 220. There are other suppliers of these cells that I am looking into so I have certainly not given up on them.

I did some prototyping of a pack by making up some end plates so I could band the pack and get good compression on the cells. Does anyone know how much pressure you need to need on the cells?

My design uses a .120 aluminum sheet cut and bent to serve as endplates. To make fabrication easier I made a plywood template for the flat pattern of the plates. I should have used MDF but I happened to have a correct sized piece of ply laying around

I then used a .25" carbide router bit in a normal router and now I can make a blank in less then a minute.

I made one up using some scrap aluminium I had laying around and the first tab I bent promptly broke off. I guess it's T6. So 30 seconds with the torch and I annealed it so I was able to bend it with hand tools. Not ideal but works for proving out the design.

Here is how the end plate looks on 7 of the cells I have.

I am going to do a bit of tweaking of the design and see if I get get some 6061-T0 otherwise I'll just aneall the stuff I have and make a prototype 1p8s pack.

[kerrymann]

Well today the conversion started in earnest. I was waiting for my adapter and hub to come but I got the answer of "it'll be done next week" for the third time. I saw someone post that Electric Car Company could not get a delivery date right to save their lives and I am having to agree. :-(

Anyway I got tired of waiting and so I started tearing the car down. I wanted to have everything but the pack kitted before I started, but what the heck... I pulled the exhaust first along with the convertible top, emptied out the truck.

This was 131lbs removed from the car! I then turned my attention to the front where I pulled the radiator, A/C PS, headers, etc. I was surprised how relatively easy everything came out. It's nice not having every nut and bolt rusted solid.

So after 3 hours of work I now have the engine all disconnected and as soon as I locate a engine hoist I will pull the long block.

It helped having my 3 year old son "working" with me.

Another 75lbs of parts plus a couple gallons of fluid means I have easily dropped 200lbs that is not going back into the car.

One part I will be saving and reusing is the AC accumulator. It will make a good reservoir for the electric vacuum pump I am using for the brakes. It's a little small but it's light, has fittings and a mount already, and it was free.

Interesting thing I found was the AC compressor was MISSING. Something the previous owner blatantly lied about when he said the AC worked. :-/ There were quite a few things about this car that would have been a real pain had I not been converting it. You would think a Pre-Law grad would have had better ethics... never mind...

On the bright side a guy bought the stock catback for $50 (got to love CL) and I found a place that will buy the catalytic converter for $90 (scrap platinum).

[kerrymann]

Well this morning my wife and son were out doing the weekly shopping so I decide to tackle the removal of the fuel tank since the fuel vapor and torch are not 3 year old friendly.

The first step was draining the fuel tank and line from the lowest point I just bent down one of the lines from the engine bay and into a 5 gal can.

I then pulled the fuel pump assembly out which gave me great access to the tank. I used a hand pump to siphon out the last bit of fuel from the tank.

Then I filled the tank with soapy water. Make sure you leave the filler neck on so you can fill the entire tank. Luckily today was nice a windy so with the garage door open I had great ventilation.

The next step was removing the tank. It's held in with 4 bolts that are easily removed but the problem is to drop the tank you need to pull out the rear sub frame. So instead I decided to cut out the sheetmetal above using a oxyacetylene torch. I need the sheetmetal out anyway because I need the space for batteries. This is not for the faint of heart. I doused the area with water to minimize the chance of igniting the insulation but did have a few minor flare ups due to all the oil suck underneath. The pass rear diff seal was leaking and slinging oil everywhere. If you do this make sure you fill the fuel lines with water too. Again don't try this at home unless you know what you are doing.

I am draining the tank of water and will get around to start the fun part of yanking and cutting.

But that will wait for another day.

[drgrieve]

One thing you can do to minimise the ah difference between cells is to match the paralleled cell to the ah average of your pack.

See this thread for more info: http://www.diyelectriccar.com/forums...ad.php?t=67805

[kerrymann]

Originally Posted by drgrieve

One thing you can do to minimise the ah difference between cells is to match the paralleled cell to the ah average of your pack.

See this thread for more info: http://www.diyelectriccar.com/forums...ad.php?t=67805

Thanks, I have been reading up on Electric Porsche's build and kakheath's. That is definitely what I will do but the wider the ah range the more challenging the matching. The way my pack is designed now I will be doing 2 packs of 2p100s which may make it impossible with this large range of capacity. I have one outlier in the 8 so if I through out that one cell the std deviation becomes much more reasonable. I am talking with the seller now about what he will guarantee as I can't eat 12% in "bad" cells.

[kerrymann]

BTW I did figure out why I couldn't get the 40amp charge discharge on my PL6. The FMA cable was pinned wrong the positive which was supposed to be on pin 9 was instead on pin 7. This is why I was getting a bad cell count warning. The tech support guy said they must have sent me a wrong cable (xh?) but a quick change and I can now overheat my "heavy duty" test leads at 40 amps.

[kerrymann]

Old engine out, just waiting for the new motor

Well today I pulled engine because I finally got a buyer for the engine from my CL ad. He bought it for $650 and the best part was he brought a engine hoist to pull the motor. It went pretty easy once I got the starter pulled.

I would love to install the motor but I am STILL waiting for my adapter from Electric Car Company International. I was told it would be delivered in less then a week and a half of payment. It has now been about a month and a half!!!! I knew I should have just built my own. Buying one was supposed to be faster and easier.... yeah right. It is supposed to be delivered on Monday, we'll see....

Until the motor adapter and hum finally arrives I have to sit in as the powerplant. Unfortunately my power to weight ratio is much worse then the 9" motor.

[njloof]

Looking good, man. I think you're gonna be solidly ahead of me, I'm pulling my engine next week.

Sorry to hear about your adapter plate woes, mine arrived very quickly from EV Source.

[kerrymann]

Originally Posted by njloof

Looking good, man. I think you're gonna be solidly ahead of me, I'm pulling my engine next week.

Sorry to hear about your adapter plate woes, mine arrived very quickly from EV Source.

Thanks. I actually feel like things have been moving slowly because I have been working/traveling a lot recently. Hopefully I won't have to travel for work again until end of May and my adapter will be here tomorrow so I can start making more progess.

[kerrymann]

Armstrong power steering



Tiny update today. I did a power steering delete tonight. For cars this light power steering is really not needed. It will take a little effort in parking lots but it's really not needed. This saves me the weight , energy and and it's really easy. I have done this before on a 1987 BMW 325 track car I had for the 24 hours of Lemons, but that is another story...

Anyway there are several ways to do this:

#1: - Install a non-powered rack.
This gives it a factory manual ratio but you have to find a rack (which is not easy given the popularity of spec miata racing) and has a slower rate that helps in the parking lots but not so much on the twisties.

#2 - Depower the rack.
This is keeping your original rack and modifying it to operate manually. And there are two ways to do this the hard way and a really easy way.

#2a - Sealectomy
Which is to pull the rack apart and remove the internal seals and reassemble it:

http://www.flyinmiata.com/tech/depower.php

While it is the *best* way, I think it is overkill.

#2b - Plug and loop (what I did)
Here you start by plugging the ports from the power steering lines. If you just did this the steering would be very stiff because you are having to pump the fluid back and forth. To solve this, you cut the lines small lines that go from the valve to the rack and the turn the steering lock to lock to blow out the extra fluid. This will not remove all of the fluid so it will still lubricate the rack and pinion gears. To keep dirt, water, condensation, bugs, etc from getting it you put two short pieces of hose between so when you steer you just move air from one side of the rack to the other.

I actually reused some of the fuel hose I removed with the fuel tank. I know people that have done this to their miata's and 7 years later they are still going strong.

In the end it cost me $0 and took 15 minutes.

Simplify and add lightness.