The last two weeks have brought to light Murphy's Law with avengeance. If it can go wrong it will.

Started the low rpm testing and it went fairly well with the stock wheel and 8 transistor board, knocked off a couple of test runs showing that contrary to expectation the low speed 180 rpm produced the highest Ratio for the Primary output to Charge discharge 0.64 to 0.66. Then all started to go downhill!

During one run after a battery switch it was noted that the Charge battery voltage dropped off a few tenths of a volt when restarted and the charging time increased to 10 hours for a 3 Ah (amp hour) battery. Not good! Shutdown the test setup for overnight and restarted in the morning - the wheel only accelerated to 170 RPM (280 is normal). Sooo, switched coil trigger wire to no resistor and it accelerated to 280 RPM. Scratch of the head here. Tried various gaps with the same arrangement - same basic performance. Then tried switching from no resistor to 12 ohm resistor while the wheel was up to speed. Yikes, the wheel accelerated another 20 RPM to over 300 RPM. This was repeatable over a normal range of coil gap. Playing with additional resistance increased the speed up to 320 RPM.

Something has changed!

Since the low RPM is an area for further investigation, continued to take data to get a further feel for operation. Adding additional resistance would increase RPM up to a point (210) and then start to drop off again. Ran a number of tests with the performance as noted above. Interesting!

The last run for this board was started on 2/20 and nothing happened from power up and the the spin of the wheel. NADA! Wheel did not accelerate! Checked the Amp draw and read 5+ amps. Immediately shutdown. Heat Sink on right side of board hot! Traced the fault to one transistor that gave up the ghost.

Pulled out the other 8 transistor board (issues from first day of operation - may be operator error). This board will not accelerate past 160 to 180 RPM w/ and w/o the base 12 ohm resistor, but will still charge a battery at a decent ratio.

So there are two boards now with issues and this effectively shuts down any further testing until these issues are corrected. Shutting down the Lab for March and heading South away from the Tundra.

In closing, it should be noted that the trusty used NAPA garden tractor battery (used as a Charge battery) had deteriorated to under 2 Ah after being charged many, many times to the 15.3-15.4v level. Goosed the charge level to 15.6-15.7v for one run and gained back two hours of discharge time (1 Ah). Of course this will deteriorate with additional 15.3v max charge levels - seen this a couple of times already. Granted, this battery is long in the tooth (old) - purchased in March 2012. Will try to rejuvenate this battery if possible by following JB's method...

Time to blank out,
Yaro