Thursday, January 17, 2013

Christmas for the evTD

A project like the evTD is never really "finished" and there is always something to refine or improve. There was literally no time to shake down the car between the time I stopped work on it and towed it off to Cape Girardeau for EVCCON. Once I got there, I noticed that running at night made the controller error light blink. The controller quit a few times when I applied the brakes at a stop light, but always restarted right away. I thought I had a controller problem, but it remained a mystery.

After I got home, my excursions were mostly in the daylight and no issues. Finally I drove it to an orchestra concert and drove home after dark with the headlights on and when I saw the error light blinking, I glanced at the voltmeter for the 12 volt system and it was hovering about 11 volts. Adding brake lights or turn signals took it below 11 volts. Clearly my 30 amp Iota DC/DC converter wasn't keeping up with the power demands of my 12 volt system. After a conversation with Steve at Rebirth Auto, I decided to upgrade to a 44.5 amp Meanwell DC/DC Converter.

It arrived just before Christmas, so I had the wife wrap it up as my gift from her. Santa strikes again!

Here is the under-hood with the Iota as originally configured:

and here after the Meanwell was installed in place of the Iota:

Not much difference visually, but the first after dark run proved it was a worthy upgrade as the voltage stayed pegged just above 12 volts with all the lights, brakes, signals and wipers running.

The Iota was never a problem when it was installed in the e-Bugeye, so the difference in the evTD would have to be the coolant pump and fans. The e-Bugeye was air-cooled, but with the evTD's Soliton1 mounted directly above the Impulse9 motor, liquid cooling was a necessity in Texas heat. That added just enough current draw to put the Iota over its 30 amp limit, resulting in voltage sag. Now there are no alarms from the controller with the added bonus of brighter lights all around.

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