Thursday, September 5, 2013

Continued progress

Over the past several weeks I have continued to test out the Arduino based Alternator Regulator.  It has gotten to the point where I now am using it as the primary regulator and the source code is getting rather stable.  But I continue to find problems with the hardware design, today’s admission is around the high voltage switching regulator - it is just not stable.

It is operating outside its design frequency, has very poor response to transients, and is present as much as a 100mV ripple in the +5!!!   All of this is enough to zero out the Bluetooth, and I am sure lots of other things are impacted.

So, in the redesign I will be going back to a liner regulator.  Either a standard LDO with a pre-scaling transistor, or something like the TL783 form TI.   At issue here is when running with a 48v system, there will be upwards of 3w of heat displaced with a linear regulator!

But, it will be stable....  

And I have been thinking more on application - specifically the placement of the Amp shunt.  IF we are really looking to understand the condition around the battery, then I am thinking it makes more sense to place the Shunt at the BATTERY, as opposed to at the Alternator.   Doing so would allow us to know the true state of the battery, independent (and accounting for) and house loads, and/or other charging sources.  

It would however preclude managing closely the load the Alternator places on the engine.

But I think there is sufficient flexibility in the firmware to allow the user to use it for either application:   Better regulation of large alternators on a house battery, as well as doing things like limiting the load placed on an engine if one wants.

All depends on how it is hooked up and configured.

So, will continue to work through issues with the firmware and ge ready to do a hardware redesign this fall.   One open question I have is:   Should I continue to use as many Through Hole devices as I can, or give in and start moving to SMT for things like blocking Diodes, resisters, etc...


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