Back in DC/DC again

Despite the troubles I was having before, the DC/DC converter has mended itself and appears to be working entirely as it should. It looks like the problem was caused by enabling the converter with the ignition signal before the precharge was done. The idea being that the precharge circuit is usually used in situations where the converter is disconnected from the pack when the ignition is off, so that it soft-starts itself and starts running on its own when it is energized. The enable input apparently overrides the soft-start procedure. When used with the enable input the converter is supposed to be connected to the pack all the time. The converter is usually not meant to be run using both like I am. So, if I switch on the pack and then switch on the ignition too soon it will close the main relay inside under the cap charging load, which probably caused the relay contacts to lightly weld shut. I spoke to Belktronics about the problem, they recommended testing the precharge circuit by attaching the converter to the pack through a 110v lightbulb- the first time I did it I got a big flash as the caps charged. At some point after then the fused contacts seem to have un-fused and the precharge circuit works OK again. I just have to make sure to always leave it adequate time to precharge before enabling it.

Posted on July 15, 2010 at 9:49 pm by Henry · Permalink
In: EV Miata

Leave a Reply