Basically we've identified that the current motor & controller isn't quite up to the task of driving this car. One critical weakness is cooling the controller, and the other is that one of the batteries has a weak cell. So long as I go easy on it the car seems to handle my daily commute. But I really want this car to do much more. I have plenty of vehicles that can handle short and medium distance travel, this car needs to handle longer distance travel and reduce the use of my gas car to once a month or less.
Starting with a couple pictures of the engine compartment's current layout.
The new motor (pictured below) has a 9+ inch diameter or a bit less than 5 inch radius. The existing motor is a 6.7" diameter. By my measurement the distance from the center of the existing racks is approx 5 inches, the diameter of the motor is slightly less than 5 inches.
Hence the new motor will be a tight squeeze. Hence it would be good if the battery racks could move a couple inches. Fortunately it seems the battery racks aren't bolted to the frame, instead they're bolted to the motor mount as well as to a bar that's also a second motor mount underneath the motor. That is the motor has two mounts - one serves as an adapter plate attaching to the transmission, and the other is this bar underneath the motor. The bar doesn't appear to be attached to anything other than the motor, however. It means that most of the weight of the motor and batteries is resting on the motor mount.
The battery trays look like they should be bolted to the car - but they aren't. Instead there's a bit of foam stuffed under them between the tray and the car. That seams odd but on the other hand the tray-like area in the motor compartment isn't really sturdy structural, it's just there.
The other thing to notice is the controller. I'm going to be replacing the controller and the new controller doesn't look like it will fit very well. The existing controller is 7" long, 4" wide, 3" deep, or thereabouts, while the replacement controller is 12" long, 7" wide, and 4" deep.
This is a Curtis 1231C - it weighs quite a bit - has better built-in heatsinking than the Alltrax - but is not programmable. The heatsinking even has this channel that you could run a water pipe through for cooling, maybe.
The thing is it's a lot bigger - bigger enough to not fit where the existing controller sits.
What I'm thinking is to build a tray for the controller to sit on, and have that tray bolt to the frame, and to make sure the tray also acts as a heat sink.
Either that or I'll be getting a Kelly 144v controller because those are programmable. I gotta be able to geek out on the controller, right?
This is the new motor. Netgain Impulse9. It already has a VW clutch and adapter plate. The people at Green Rides were working on mounting this motor & controller onto a kit-car which has a VW transmission. Therefore I know that this motor will bolt directly to the transmission on the Karmann Ghia.
I've had a recommendation for a local car shop to work with - It's a shop that Richard Hatfield knows and claims is interested in or experienced with EV's. I'm planning to have an experienced shop do the motor swap because - heck -I know nothing about transmissions and motor swaps, it's better to let an expert handle it.
This motor will work at 72 volts so I intend to do the motor swap now and continue using the existing controller. It will stay that way until the new battery pack arrives at which time I'll swap the battery pack and controller in one go. The new motor is more than enough to handle this job so it should fix the bit about the motor overheating.
I really should do something about heatsinking the existing controller, then, as a stopgap measure .. it's gonna be approx 2-3 months before the new pack arrives from China and is ready to go. Hurm.