Sunday, May 12, 2013

Maker Faire and Explosive Semiconductors

The San Luis Obispo Mini Maker Faire went great. The car got a lot of attention from passerby, and there has been a significant upturn of opinions on the car since its conversion to lithium batteries and the improvement in range. On top of that, I only had two semi-crazy people come up to me claiming that all the batteries in my car weren't necessary and that they had developed a device that could "make amps without power". It seems there's always a few. Here's a picture of the car set up at the Maker Faire, donning posters with information and FAQ's.


The car has been performing wonderfully in the past week that I've been driving it. And it is still performing great despite a recent, shall we say, hiccup. The charger in the car, a Zivan NG5, has performed quite well since I first put it in when the car was initially converted. And despite the need to send it in and pay $75 every time the need to change a charge parameter arises, it was a nice enough high powered charger. The use of the past tense was not unintentional, as the charger felt the need to blow up every semiconductor component within it on Friday. I have since ordered an Elcon pfc4000 to replace it in the hopes of having a better experience than dealing with the Zivan USA support, which quoted me at least $500 and several weeks to repair the charger.  So in the meantime, there are about 40 miles left in the battery pack (which luckily got a nearly full charge before the charger went kaput) which should last me until the end of the week when the elcon charger is slated to arrive.

Tuesday, May 7, 2013

It Lives!

After a bit of frustration with the charger, two broken drill bits, and sore fingers from hand tightening bolts, my car is at last on the road again. Just in time for the SLO Mini Maker Faire as well which should provide a nice opportunity to show what I've done. If you're in the area, stop by!


Here you can see one of the battery packs under the car bolted in (that's what the drilling was for). There's a lot more ground clearance than with the lead batteries; almost 6 inches at the lowest point. This made for a pleasant surprise when I pulled into a parking lot and saw a speed bump. I inched towards it expecting to hear the familiar scrape of the steel case of the lead battery pack, but instead just went right over top with a grin. While this may not seem that exciting, it's been a long time coming, and I'm sure my local stores will appreciate the lack of further chunks missing from their speed bumps. I'll update with more pictures once I get the chance to clean up the car and the wiring under the hood.
The BMS performed quite well on its maiden voyage and showed a 90% charge remaining after the slightly more than 5 miles of driving I did today, which is great news considering how excited I was to see how the car would perform with so much less weight. All the cells seem to be well balanced with the exception of one that seems to be dipping a little bit more under load. This may be due to a loose connection so I'll need to take a look at that. Overall I'm very happy with the system.
Until next time.