Sunday, October 12, 2014

Released v0.1.3 of Source Code

This morning I posted v0.1.3 of the Source Code for use with the Smart Alternator Regulator.  I also updated the documentation to match.  Refer to the Source Code tab and Documentation tab above.

There are a few key additions to this source code, and I would encourage all to install this update.  Changes include:
  1. Corrected bug that caused early termination of Acceptance in some configuration states.
  2. Scrubbed the CPE tables to assure default values reflected the 'normalized' 12v/500Ah battery.
  3. Greatly revised the LiFePO4 CPE entry.
  4. Added feature-in option to 'force to float' in combination with LiFePO4 CPE.
  5. Added CPE options to exit Float and/or post-float mode based on accommodated AHs.
  6. Changed both Voltage Multipliers and Battery Amp Size multipliers to allow Floating Point numbers.
  7. Added ASCII command to compensate for reversed connections to the Amp Shunt.

LiFePO4 oriented changes:  Two of the items (#3, #4) are directly a result of talking more with folks about how to address the needs of LiFePO4 batteries.  Item #5 also can help.   In short, I have backed off the default CPE for LiFePO4 batteries to very conservative termination numbers.  Now Bulk to Float will occur at 14.0v, with transition into Float occurring at the 10% of battery acceptance capacity rate, or a max of 1 hour.  All told, this should get LiFePO4 batteries into the 95% or so SOC, and also be well under the trip points of most BMS systems.  If you want to drive your battery harder, modify the CPE using the ASCII commands - after all, the Smart Alternator Regulator is very flexible!

There is also a new capability to force the regulator into float by activating the Feature-in port.  It is intended that this can be used to provide a loose coupling with an external BMS system, depending on how you set things up.   #4 above is only enabled with CPE #8, the one associated with LiFePO4.   Over time I am not sure if this will prove useful, and feedback would be appreciated.

#5 is a major addition and change that is enabled by the current measurement capability of the Smart Alternator Regulator.  Float mode is traditionally intended to 'keep' the battery in a stable state, and often based on measured voltages.  But in fact, what one is really trying to do is keep the energy in the battery while being able to support house loads via the alternator.  Monitoring Voltages can give an indication of this, but monitoring energy withdrawn is a better indication.  A new exit criteria based on Amp Hours withdrawn after entering Float has been added to Float and Post-Float modes.  These can be modified via ASCII commands adjusting the CPE's

#6 also addresses greater flexibility.  Rather then fixing the volt and amp multiplier adjustment factors used to scale the CPEs for batteries other then the normalized 12v/500Ah battery, floating point number can now be used.  If you have a 32v/400Ah battery, then use 2.67 and 0.8 respectively to fine tune things.

And #7 is a 'Oh Man' thing.  If you get the wires to the Amp Shunt backwards, rather then having to rewire things - just 'flip the switch'!

A side note:   Because of all the changes, specifically in the CPE, if you already have configurations saved in the Flash of the CPU, those will be reset and you will have to reconfigure your regulator via the ASCII commands again.  Perhaps down the road an external app hosted on a PC or such can help automate these types of transitions, but there jsut is not sufficient horse power in the little ATmega328 uC to do such things. . . .

CAUTION:  As with prior releases, I have ONLY been able to bench-test this release.  I hope to get back to the boat this Winter and will be able to do some live testing.  But until then, be very cautious things  - and do give me feedback on how things work!