Parts On Order / Precharge

No mechanical work on the car to update on, but I have been finalizing electrical components and making orders.

My controller will be the ElectroCraft EVMTC60-192V 400 Amp. http://pages.interlog.com/~dgv/dc.html Estimated delivery is 5-6 weeks. The company isn't well known in the EV community, but they've been very responsive to my questions, offer a 1 year warranty, and have a great price. I've decided to try them out as opposed to established older designs that get more expensive by the month or other newcomers that have serious questions in reliability. Also, this controller has built in over-speed protection (when in neutral) and should easily handle a fully charged Lithium Phosphate battery pack.


For Christmas I got a second contactor (with auxilary connection for status light)...


ammeter...


and novelty horn. The car's nickname is Bumblebee, so I'll have to record the Transformers theme song into the novelty horn to play at car shows. :-)


I also ordered a few other components. A 400 amp fuse with holder (which is huge by the way)...


and a precharge resistor (1k Ohm, 50W)...


Taken from the diyelectriccar.com website... "The PWM motor controllers common in EVs have a sizable bank of capacitors on their input. When you apply a Voltage across a capacitor it initially appears to be a short-circuit, that is, the Voltage across the capacitor is zero. If there is very little resistance in the circuit, e.g. a closing contactor with no precharge, then the current will be very high. Nearly all of the traction pack voltage will be across the closing contacts. The large Voltage difference and sudden high current (known as an inrush current) can cause damage to, and in extreme cases, welding of the relay contacts. Also of concern to some is the stress on the controllers electrical components caused by the inrush current. This can all be prevented by the use of a precharge resistor across the contacts of the main power relay. The precharge resistor allows the capacitors in the controller to slowly charge BEFORE the contactor closes. This means that there is less voltage across the closing contacts and little or no inrush current."

I'll use 2 contactors with my setup. The first contactor will be triggered closed by turning the key to "on". The second contactor will be triggered closed by the key "on" and by pressing the foot pedal. The precharge resistor will be across the terminals of the second contactor. After I turn the key to on, the precharge for the capacitors will begin. Then all I need to do is wait a few seconds before hitting the gas (as most people do anyways) to let the controller slowly charge up. Another option is to have a delay timer to wait a few seconds to charge before the car will go - I'll decide later on if I want to go that route.

My wiring diagram is basically done, but I think I'll wait until I get the controller and all the smaller components in before I post it. Little things may change until everything is in my hands.