Wednesday, February 14, 2007

If it aint broke, don't fix it...

Well, I tried to learn more about the distributor two evenings ago and really screwed up the engine timing. The 914 runs but really sputters and jerks around when cold and doesn't seem to improve much after warming up. I have an appointment at the shop on Friday to fix my "optimizations."

On a more interesting note, I prototyped a battery equalizer with two 12V UPS batteries earlier this week. The circuit seems to work just fine and I was able to get the voltage difference between two adjacent batteries from 1.0 volts down to 0.2 volts overnight. The process is asymptotic, so there are diminishing returns as the voltage difference converges towards zero.

This morning disaster struck the equalizer in that I swapped a 47uF flying tantalum capacitor for a 1000uF low-ESR electrolytic but forgot to change the switching frequency. The high-current FETs overheated and the plastic protoboard melted to my desk. Murphy's Law says that experience varies proportionately with equipment ruined. Ugh. I'll post a schematic in the next few weeks so other people can leverage it.

On a brighter note, ElectroAuto replied to my second e-mail and said that the new suspension for the 914 to handle the extra battery weight should go out this week. Once I have the suspension, I can have the shop install it and I can get to work. Let's cross our fingers...

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