The Chilton's manuals I have do not go into good detail about all the existing Bugs wiring.  For example, the key switch specifics are pretty lacking / incorrect -- one page lists the "Start" wire as Blk, and another lists it as Yel/Blk.  That seems incorrect.  Also, no mention of the "On" wire color.  And no mention of the 50 other wires exiting the steering column!  So on to other resources....

Found a mention of another brand of service manual (Bently, found this one), but before buying with fingers crossed, going to look at alternatives.  


Jackpot!!!  At first glance, looks like this will clear up everything!  Clear wiring, detailed symbols, test points, and a detailed key that even includes fuse descriptions!  This is awesome (assuming it's correct for my 73 super..fingers crossed)!!  Found from here:

Before my edit above:

Found this from for a 72:

Key switch Operation:

And some notes from a post here:

  • Looks like Red 4.0 mm is incoming power
  • With the ignition switch in the ON position, two wires will be shorted and allow current flow. Likely the red (#30) and the black (#15) wire.
  • The black/red (#50) wire should not be connected to anything in this position.
  • Turn the key and hold it in the START position, all three wires should be connected together (red, black, black/red). This is how the red wire powers BOTH the ignition (#15) and the starter solenoid (#50).
  • The grey wire is optional and may be either grounded or powered while the ignition is OFF with key IN. This would set off a door buzz

Going to put a battery in her this weekend, bust out the meter, and do some testing to at least figure out the key switch and how I'll integrate it with the Zilla controller.


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Going thru how exactly this guy will be controlled, one hang up is becoming apparent.  Emergency shut-off!  It's not recommended to rely on a contactor to disconnect power in the event of an emergency, which makes sense.  Seems a lot of people use this switch:

Gigavac Maintenance Switch HBD41AA 1000V 400A Continuous Hermetically Sealed

But, looking at the specs ( all the ratings are at 24VDC.  Nothing at the 140+ we'll be running.  A little scary.

Some people talk about a DC circuit breaker located remotely, with a cable operated connection to the driver area.  Seems like there must be a better way.

Found a nice website made by someone involved with the design of the Zilla controllers.  Thinking I'll find some nice info here.  On to reading...

Not a lot of info on the above site, but after a lot of other reading ti looks like the only legit option is a rated circuit breaker.  The problem is, a new one rated for 150+VDC and 500A is thousands of dollars.  Ebay has a lot of used units, but at the moment, cannot find one reasonably priced (under 300-400).  Saved the search, and will keep my eye out.

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Round and round on the design of my battery system, and a lot of learning along the way.  

Current battery plan is for a 144 volt system.  Looking to use 42 Nissan Leaf modules.  While these have longevity issues, this is not a daily driver for me, and long range is not super important, the price was right.  Lead acid is out in my mind, buy Tesla modules were crazy expensive, Chevy Volt were too oddball for my config, and other battery types (CALB, LifePo ext), where just too expensive.  So Leaf it is.  I wanted to get to 144 volt to make sure my top speeds were well above 60 MPH, and 2 in parallel gives about 20KWH of power.  A quick back of the envelop calc -- 4 miles per KWH = about 80 miles of range for this pack.  Considering this is for fun, and I want to be heavy on the throttle, if I can get half that 80, I'd be very happy.

Some good data on a thread I stared at the DIY Forums:

Long story short, need to be careful with overcharging lithium cells, so that must be considered when planning the wiring system.  This is a great document noting the benefits and drawbacks of different configurations:

So, the final plan (at least as of today), is a 42S4P configuration per the following schematic:

24 Modules will go in the back seat area, and all be wired to the Controller portion of the BMS.  This maxes out the BMS connections.  The balance of the modules (18) will reside in the trunk, and be connected to the Satellite BMS.  So each "pack" location will have it's own BMS.  Putting more modules in the back seat, would require wiring from the Satellite BMS to both the back seat area, AND the trunk area, complicating wiring for sure.


Charger and DCDC Converter spec TBD



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Original Plan A was a new AC motor (Hyper9) with Tesla batteries, but after running the numbers the cost was going to get crazy.  Probably $20k when all said and done, and certainly could not justify that much into an old bug.

So Plan B is to go cheap.  I'm actually really excited about this plan.  Per all my research these old big, fat, heavy tow motor DC motors are beasts that can be over sped and worked hard, and they last forever.  Couple with a used controller, used Leaf batteries (maybe not the best performance, but great pricing), and anything else I can find on Ebay or the like should save good money, and get great performance.  Quick back of the envelop calcs looks like I can go this route for under $10k

Performance with Plan B should be as good if not better than A.  With the big DC motor, and the money saved, I can get bigger controllers, fatter wire, and overall plan on a beefier system.  Quick calcs -- if I can pump out 500A out of a 1000A controller @ 144V I'm looking at almost 100HP.  Not sure if the batteries can pull this off, but the system will be capable, and batteries could be upgraded in the future.


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Really cool looking mini "Corvette" might be worth a look if I every have the opportunity to do another build -- Opel GT.  An example: Matt's 1970 Opel GT - Project Log

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