4. Charging system
The Charger arrived on November 22
This 3.3kW charger can charge to a maximum of 720 Volts, just enough to top off the BMW's battery pack.
This is compact enough to fit into the BMW's optional battery compartment that was empty from the factory on this model, since they put the 12V battery in the trunk for better weight distribution.
The charger comes with software to program the charging profile.
It can be plugged into 240 VAC outlet if available for charge time around 3 hours.
If plugged into a 120 VAC outlet, the time to charge doubles.
The charger's output is isolated from the AC mains for safety.
If all goes well, I will mate the DC/DC converter to this cooled platform to make the air cooled unit more compact and fit in the same compartment.
June 1 2008 update
The original plan was to combine the DC/DC converter heatsink (presently air cooled) with this water cooled charger, since the cooling resource is available to be shared. Because of the non-square inner compartment shape, the DC/DC converter will not fit, even with it's air cooled heat sink removed. This will force it to the trunk, mated with the 12V standard battery that it will be delivering current to anyway. There is a good location for it there and will not cause a noise issue from it's fan since the trunk is isolated from the interior.
There is a benefit from this conflict that actually works out very well. I also needed a place to put the electronic controller for the Air conditioning motor/compressor unit (wasn't in my original plan, but needed for this A/C pump). Here is the perfect solution:
The air cooled heatsink that this circuit board is mounted to will be removed and the circuit board will instead attach thermally to the water cooled body of this charger unit. They use the water cooling resource at different times.
I will construct an aluminum enclosure around this circuit board as part of the attachment and mounting of this complete assembly.
There will be one more orange wire attached after a little sheet metal work in the upper right corner. Otherwise, the location of the wires and plumbing work out perfectly with this orientation.
The water cooling lines will enter and exit through hole in lower right of compartment.
